Weak Spark On Small Engine

Testing the Spark. If your engine sounds like it isn't cranking over at the usual speed, try jump starting. Magnetos are also used on many small airplanes (for example, the Cessna 152 seen in How Airplanes Work) because they are. A spark arrestor on the exhaust port can reduce the chances of such a fire. Blue spark is cold in comparison to ultra-violet. Ignition Systems. This will rule out a weak battery. If the firing end of a spark plug is brown or light gray, the condition can be judged to be good and the spark plug is functioning optimally. Remove the spark plug boot. ) Spark Plug wires E. I'm not familiar with your engine, but I know with small engines such as lawnmowers and tillers, the flywheel will shear the key and turn on the crankshaft. to/2IjN42R Today we got a Honda GX120 and it has a random no spark issue. Whether it's your mower, tractor, or handheld equipment, P&P Small Engines is here to answer all of your MTD troubleshooting questions. I did the test where you pull the spark plug from cylinder head and ground it to the motor. You have a defective coil and should replace it (B). Ignition Spark Tester LED lights tests for weak/faulty ignition systems DISCONTINUED FROM INVENTORY SEE DESCRIPTION FOR REPLACEMENT. Small Engine - No Spark Sign in you will still have a weak spark (or a shock). 3 milliseconds or longer at idle with a. Re: 1963 Merc 60 6hp - Weak Spark It don't sound like a mechanic more of a cobbler, first the engine came with copper plug wires and if he used resistor wire it don't work well on magneto ign. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. Turn the lawn mower's ignition switch on and pull the rope to spin the flywheel. But on an automotive engine with a higher compresssion ratio and under transient conditions the yellow spark can get quenched thereby causing a misfire. Anything and Everything You Want to Know About Spark Plugs RPM situation where a weak spark could promote fouling. Checking Engine Compression. The other cylinder has great spark and the engine runs fine on that one cylinder its just weak when the blades are engaged. Others develop the ignition spark using a magneto. When an engine pings, it releases pollution into the environment in the form of nitrogen oxide (NOx) and raw, unburned hydrocarbons (HCs). If the magneto is generating the proper ohms, check to make sure the spark plug is working properly. Ask Your Own Small Engine Question. You should get some kind of spark, although if you turn slowly the spark may be weak. Learn to fix a misfiring engine with our repair guide. Small Engine Carburetor Cleaning Tips / How to Clean One Piece Flow Jet Carburetors Why Small Engine Spark Plugs Fire with Each Revolution Causes Weak or No Spark. If that doesn't get you a hot spark, the coil may be on its last legs. Asked in Spark Plugs and Wires, Small Engines, Tecumseh What is the correct spark plug for Tecumseh 5 hp motor ? Any auto or small engine repair shop will be more than happy to help u. The most likely problem is: A). By LawnMowerPros. If there is no spark, this indicates that the spark plug is defective and should be replaced. The mixture starts the engine. With a number of frequently asked questions, we'll guide you through easy at-home steps to troubleshoot your MTD outdoor power equipment from the comfort of your own garage. This can be indicative of either a weak magneto or deteriorated plug wires. It took me three days to learn this as I cranked and cranked on a motorcycle. it is weak causing incomplete. If you still have no spark replace the ignitor with a known good one, or use the 97-UP coil with built in ignitor. If the engine has a distributorless ignition, the ignition coils must be disabled to prevent them from firing. With the best in magnetos and accessories, we offer a full line of parts and accessories including ignition system wires, billet side covers & magneto kits. Prevent more. How to Start a Stubborn Weed Trimmer With a Thimble and Some Gas. I'm getting a weak spark, and. i have a briggs and stratton 650 series quantum engine, only 2-3 years old, the engine would start randomly/once in awhile and other times would not start, this has been occuring for about 6 months, when the engine DOES start it will run fine till i shut it off, then will not start again until it has fully cooled down (the next day), i have been slowly trying to isolate the problem, the carb. Here's what I have: 56 Chevy w/ 350 small block w/ Mallory Magnetic Breakerless distributor w/ MSD Blaster 2 coil. A basic Sonic 5-door is only $1000 USD more than a mid-grade Spark. If the gap is fine, disconnect the kill wire from coil and check for spark. My engine seized up and I'm now looking at $4000 replacement cost. Several components in the system need service at regular intervals. Orange and yellow come from particles of sodium in the air ionizing in the high energy of the spark gap. Anything less and the engine will be weak, run rough, stall, and misfire. Could it be that there is just too much compression in the engine and this is causing the spark plugs to be expelled? If so, what can be done. By LawnMowerPros. If you get an 1/8" or so of spark, that should be enough to fire. EPA emission regulations for SORE (Small Off Road Equipment), are certified to operate on regular unleaded gasoline, and may include the following emission control systems: (EM) Engine Modification and (TWC) Three-Way Catalyst (if so equipped). It has a random, weak spark. Sources 3 years in a small engine repair business owned by my dad and self taught/schooled maintaining 4 lawn tractors + working at the shop. How to Start a Stubborn Weed Trimmer With a Thimble and Some Gas. Small Engine - No Spark Sign in you will still have a weak spark (or a shock). 2 Stroke no spark help? now just have light spark, it seems a bit weak. With that said, there are large wires going from the battery negative terminal to the engine and body. If there is no spark or it is very weak, this means that the coil inside the magneto of the engine or the breaker points of the engine need to be repaired. Spark plug heat range is too cold for the operating conditions. With most gas engines for boats it'll be hard to see the spark in daylight, one of the. 8L Ford F150 (or E150, Bronco, Crown Victoria, Grand Marquis, etc) is fried and causing your vehicle to NOT START or not the cause of the problem. If the gap is fine, disconnect the kill wire from coil and check for spark. Briggs Stratton small engine. A spark arrestor on the exhaust port can reduce the chances of such a fire. switch opens, and it will restart. My magneto generated a very weak spark, so I replaced the coil and condenser. Clean or replace fuel line. If the magneto is generating the proper ohms, check to make sure the spark plug is working properly. I pulled the brandy new plug, and jumpered it the spark is blue but looks on the weak side. Weak Battery. Non-resistor spark plugs deliver a more powerful spark. I don't think that Kohler had the sticking valve problem and you would have seen the open exhaust valve. Briggs & Stratton 5hp 130202 -no spark after new ignition coil. The duration of the spark line for a "good" cylinder should usually be 1. SMALL ENGINE REPAIRSMALL ENGINE REPAIR 366 SMALL ENGINE TROUBLESHOOTING CHART Problem Possible Cause Solution Engine fails to start or is 1. A bright blue spark is best. The strength of the spark is revealed in the color. A weak spark is the first sign that the ignition coil may be failing. The main components of this system consist of an ignition coil, coil driver, distributor, spark plug wires, and spark plugs. Most likely, there is a simple, easily remedied cause. In either of these events, use a small oil can and squirt a little oil into each cylinder, then repeat the compression test. So a small intense spark is much better than a big, weak spark, especially when dealing with richer fuel mixtures and more volumes of fuel being burned. Most of the people finding there way to my website or are in search of information on Tecumseh ignitions so in this up-date, I put that first, Topic 1. Some small engines require a battery to supply electrical power and the ignition spark. A spark plug can deliver a weak spark (or no spark at all) for a variety of reasonsdefective coil, too much compression with incorrect plug gap, dry fouled or wet fouled spark plugs, insufficient ignition timing, etc. Coils bad? If so, is there a NAPA equivalent that doesn't cost like the Onan coils?. If you own several small engines, it may pay to buy a tester To learn how to use it, read How to Test an Ignition Coil. I have suddenly developed a weak spark and now it wont start. I have a question, After reading as many posts as I can find I have not found the answer. As the flywheel rotates, the magnet passes the ignition coil inducing a voltage in it (see Photo 1). Be sure to use the exact spark plug recommended for your engine. Engine Vibration Causes – Free Auto Repair Tips July 25, 2009 4:51 pm dennisb - Auto Tool Sales DIY , Drivetrain and Noises , How To Auto Repair This Kia Rio had a severe engine vibration, see the picture below for the cause. You might be saying, "Jim why are we talking about spark before fuel?". I have a question, After reading as many posts as I can find I have not found the answer. The ignition coil must then disabled or the high tension lead grounded. if you wish e-mail your symptoms that lead you to look at spark. I can't even get it to pop,when I look at the plug its wet so it getting gas. On engines that don't have that access, you need to be a little more creative. If you are getting no spark at the spark plugs, remove the plug wires. If you've come to this procedure, you probably suspect that you have a no spark condition. Ignition Systems. What to Look For. have checked the gap on the coil, cleaned both pick-up areas. A weak spark is the first sign that the ignition coil may be failing. I used a test light at the points and the light flash's when the engine is cranking-so the distributor is good. Fortunately, replacing a spark plug is simple. Take a new spark plug and bend the side electrode out straight. Ignition cables also known as spark plug wires are an important part of your car's ignition system. In order for your machine to continue to start and run efficiently it is recommended that the spark plug be replaced each season. If your engine sounds like it isn't cranking over at the usual speed, try jump starting. Ask Your Own Small Engine Question. If one or both of these components aren't working you won't be able to start your engine (let alone use it) not matter how well it's tuned. ) - (Added 10/25/17) Need to rule out all possibilities first. (Another advantage of this method is you don't have to remove the actual spark plug from the engine block, although you should probably check the condition of the spark plug tip and regap while you're at it). By Tom Benford. Denso Iridium Spark Plug types Denso Iridium Tough Plugs. Prevent more. Fuel line plugged or kinked. After running it for a while, I've confirmed that the spark gets "weak" on both cylinders every time the motor bogs. Bad spark - A weak spark from its lead, damaged or improperly gapped plug, dirty plug, or old plug will all prevent the engine from firing when asked to start. Spark Plug Warning Signs: 1. Remove the spark plug. Engine Vibration Causes – Free Auto Repair Tips July 25, 2009 4:51 pm dennisb - Auto Tool Sales DIY , Drivetrain and Noises , How To Auto Repair This Kia Rio had a severe engine vibration, see the picture below for the cause. Watch the spark tester or spark plug, looking for a spark between the electrodes of the tester or spark plug. There may be a fault in the computerized engine control system. With ignition On, turn the engine pulley CW past the TDC mark. When you turn the engine (pull the cord), the flywheel rotates. Basically, you need proper voltage to the coil and a good ground inside the dist for the point plate, along with a good ground path for the dist itself. Checking Engine Compression. You can only see the spark in dim or darkened room. At the very least, you should certainly have the service manual as a guide. If that doesn't get you a hot spark, the coil may be on its last legs. -Start or crank the engine and watch inside the glass of the tool. 3 milliseconds or longer at idle with a. I had a spare good module which ive swapped and it made no difference. Fuel line plugged or kinked. Below is a chart of common Engine problems and some easy troubleshooting to fix the problem you may be experiencing. Most two-cylinder tractor mower engines will have the spark plugs located near the top of the engine, on opposite sides of each other. With ignition switched on, hold the shank of the screwdriver near the cylinder head and crank the engine. There is a problem with the ignition system, causing a weak spark. I an not getting any spark at all. So a small intense spark is much better than a big, weak spark, especially when dealing with richer fuel mixtures and more volumes of fuel being burned. Too small of a gap can make life too easy on the ignition to the point where the resulting in a weak spark that may not be strong enough to create a full combustion cycle of the air/fuel mixture. Small Engine Carburetor Cleaning Tips / How to Clean One Piece Flow Jet Carburetors Why Small Engine Spark Plugs Fire with Each Revolution Causes Weak or No Spark. An ignition coil is a type of pulse transformer that multiplies the low voltage received from the battery or alternator to many thousands of volts when the breaker points open and close. I swapped in the points for the left cylinder from a spare engine after cleaning them a bit with a file, and got the same results. In either of these events, use a small oil can and squirt a little oil into each cylinder, then repeat the compression test. If the spark is weak and yellow, replace the spark plug; if it's blue, move on to the fuel line. In the United States, the Environmental Protection Agency granted a waiver for low concentration blends of ethanol (up to 15% ethanol volume) for use as an automotive spark-ignition engine fuel and for up to 85 vol% for flexible-fuel engines. Using a spark plug is a poor test of the ignition system. When you connect the spark tester to the spark plug cable or the ignition coil boot (for Coil-on-Plug Systems) and crank the engine, the HEI spark tester (OTC 6589 Electronic Ignition Spark Tester) forces the ignition coil to produce its maximum output so the spark can jump across the very large air gap. Do coils and condensers and plug wires deteriorate over time when not used, or is this more likely just bad connections here and th. A great way to help avoid these problems would be to perform an annual tune-up using a Briggs & Stratton engine Maintenance Kit. When it stops, monitor the window. When the engine starts, oil is sprayed by the oil slinger all through the engine, and what is om the crankcase walls lowers the level a small amount, shutting off the engine. Using a spark tester to check the ignition coil. SMALL ENGINE REPAIRSMALL ENGINE REPAIR 366 SMALL ENGINE TROUBLESHOOTING CHART Problem Possible Cause Solution Engine fails to start or is 1. I have set coil gap at. If you still have no spark replace the ignitor with a known good one, or use the 97-UP coil with built in ignitor. If it is set off too early or too late, the fuel won't ignite and the engine. So first of all, it's best to check for a sheared flywheel key. No Spark When your engine cranks but fails to start, it could be because of no spark. It stopped running when it wanted to shift, but that had nothing to do with it when I pulled a spark plug wire and no spark. You should get some kind of spark, although if you turn slowly the spark may be weak. com, this occurs when the spark plug fails to fire, or fouls out. Uneven or wavering idling is a common symptom of small air leaks on motorcycle engines. it shows I am getting some spark but it's weak, compared to my Echo PAS-230 Weed Trimmer with same spark tester. The mixture starts the engine. A properly mixed engine will introduce a small amount of fuel to burn correctly with this small amount of air, and burning this smaller amount of fuel with the smaller amount of air produces a small amount of exhaust gas, weakly pushing the cylinder down. In-Line Type of Tester (2) Adjustable Gap Type Tester (2). If it is too large, the valve won't open all the way and if it is too small (or non-existent), the valve may not properly close, which can lead to overheating and valve seat damege. ) Running winter fuel in warm weather. There is a problem with the ignition system, causing a weak spark. If the spark is weak and yellow, replace the spark plug; if it's blue, move on to the fuel line. The basic compression test for Briggs and Stratton engines is carried out by turning the engine backwards. I did the test where you pull the spark plug from cylinder head and ground it to the motor. Most custom-built engines no longer have original cylinder heads so the first thing you need to do is figure out the necessary spark plug thread diameter, thread length or reach, and the type of. Small Engine Parts. These spark plugs have a small center electrode which means they use less voltage to generate the electric current. I have a tecumseh 5 hp engine that has or had a weak spark. 5,806 likes · 214 talking about this. The use of the correct type, brand, and heat range of a spark plug is of paramount importance in today’s emission certified engines. ENGINE RUN-ON, DIESELING -- RO-101 DIESELING, that nasty tendency of an engine to continue to run on, coughing and sputtering, after the ignition is turned off and there is no more spark. 45 cu-in) single-cylinder air-cooled 4-stroke internal combustion small gasoline engine with horizontal shaft manufactured by Kawasaki Heavy Industries LTd. an inline spark tester is the only accurate way to test spark quality. Being able to read a spark plug can be a valuable tuning aid. Checking Engine Compression. Check your engine air filter -- it may be dirty enough to clog proper air intake for the engine. powered spark advance system MDI has taken its place. No fuel in tank. If your plugs indicate that something is seriously wrong with your engine, ask a professional for an opinion. This action stress-tests the ignition coil. ) - (Added 10/25/17) Need to rule out all possibilities first. Valve clearance ("valve lash") can affect the way the engine runs. I had experimented disconnecting this in the past and the cruiser won't start, but now I am wondering what it is, since I also have a manual choke. If your spark plugs become dirty or fouled, it can affect how your engine runs. Spark Plug Gap setting is important for proper engine operation. A spark plug that can spark in the open air may not be sparking at all in the cylinder. If the plug starts igniting anywhere BUT the channel in the ground electrode you get weak spark and can cause spark blowout. After running it for a while, I've confirmed that the spark gets "weak" on both cylinders every time the motor bogs. A properly mixed engine will introduce a small amount of fuel to burn correctly with this small amount of air, and burning this smaller amount of fuel with the smaller amount of air produces a small amount of exhaust gas, weakly pushing the cylinder down. Interest Approach. Most two-cylinder tractor mower engines will have the spark plugs located near the top of the engine, on opposite sides of each other. To check engine compression manually with a gauge, all the spark plugs must be removed. Overheating can be caused by any number of things. If troubles persist after checking the possible causes listed or you are unable to identify the problem, call KOHLER Engines Customer Service at 1-800-544-2444 or contact your local KOHLER dealer. hard to start 2. Whether you start the engine with a pull rope or the turn of a key on an electric start motor, you're relying on the ignition system to produce a spark inside the combustion chamber. A related fact. Use a hand held electric drill or an air wrench to turn the crankshaft at the magneto nut. In either of these events, use a small oil can and squirt a little oil into each cylinder, then repeat the compression test. If the magneto is generating the proper ohms, check to make sure the spark plug is working properly. A spark arrestor on the exhaust port can reduce the chances of such a fire. Iridium Spark Plugs. of engine oil into cylinder(s). If you have spark, the tool will show. A basic Sonic 5-door is only $1000 USD more than a mid-grade Spark. If you get a weak spark then that is usually a sign the source coil is weak and not providing enough power for a good spark if the plug coil is good. Weak Battery. I dragged it out to restore it. If your lawn mower is consuming more fuel than usual or the engine isn't running consistently, try outfitting it with new spark plugs. Engine quits while running? Hook the tester up between the ignition cable and the spark plug and start the engine. Did you test the new spark plug on something else?. There are return lines and even vacuum lines on some of the new small engines (makes me wish for the old Briggs or Wajax with their deafening noise and simplicity). I thought I’d do this write up as there doesn’t seem to be as much info about this issue on here as there is on the. Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. Orange; not a hint of blue. If the spark is weak and yellow, replace the spark plug; if it's blue, move on to the fuel line. The ignition system is the starting system for your small engine. All of the spark in the world won't crank it then. Its pretty old but I would love to get it running. But on an automotive engine with a higher compresssion ratio and under transient conditions the yellow spark can get quenched thereby causing a misfire. the engine will turn over 3 times and then spark. Re: Causes of weak spark on Tohatsu 18HP 2-stroke? You need a spark tester to test ignition coils output condition, if engine is working ok, what's the problem ? If not, you just have exciter, ignition coils or CD electrical related issues Happy Boating. i get spark, but its really weak. 5 hp Tecumseh horizontal shaft engine. But in neutral, this weak push is all that's required to maintain 2300 RPM. Weed Eater 96112011501 (2012-05) Rotary Lawn Mower Parts. A weak magnet WILL result in a spark problem, be it a weak spark, no spark, unrelliable spark. Weak Spark - things to check first this is for any of you that have anemic spark and are having hard starts. Specifications for this engine call for 0. It might give out a weak spark to account for the back fire. Look for signs of damage, improper plug gap, soiled spark plugs, or a broken connection to the spark plug lead (aka wire). My magneto generated a very weak spark, so I replaced the coil and condenser. First to cover the basics - remove the small ground wire to the coil - this isolates the module, and will verify module integrity 96% of the time. Remove the spark plug boot. What would cause a weak spark? If this is your first visit to 3WHeeLeR WoRLD, please take a moment and look around. Open shutoff valve. This should remove the fuel from the spark plug hole that had seeped in during the flooding. If your ignition module or sparkplug are weak and not providing sufficient output (about 12KV or more) you may in fact see spark when tested without compression but as soon as you try to run the unit the spark disappears. Listen to the full podcast at Brighteon. It's not something to be attempted by a novice. I know it did for me. My old Echo hedge Trimmer won't start this year. I change the coil if I have a GM engine that won't start in the cold and has no spark. it is weak causing incomplete. But the Spark’s dreadful design and weak engine aren’t what landed the littlest Chevrolet in the 2013 edition of The Bad 8. You can either purchase a dedicated tool, borrow one from an auto parts store, or buy something off the internet that can bluetooth to. You should get some kind of spark, although if you turn slowly the spark may be weak. If you own several small engines, it may pay to buy a tester To learn how to use it, read How to Test an Ignition Coil. What cannot get out blocks what needs to get in. The MDI kits require use of the original engine wire harness. Kawasaki FH680D weak spark I have a Kawasaki FH680D-ES04-R that backfired and now it will not start. Otherwise, have the coil packs looked at. When your engine cranks but won't start or run, it could mean your engine is having trouble producing a spark, getting fuel, or creating compression. You should see a strong spark between the tester’s terminals when the engine is cranking. - Disconnect the ONLY the grey wire(s) from the (-) side of the coil, keep all others connected. Weed Eater 96112011501 (2012-05) Rotary Lawn Mower Parts. If the spark is weak and yellow, replace the spark plug; if it's blue, move on to the fuel line. Whatever the problem is, recognizing when your engine is running lean is important for maintaining the health of your car. I have set coil gap at. Detonation (Spark Knock )(Detonation) Misassembly (opps!) ENGINE OVERHEATING. hint the fould plug. With a number of frequently asked questions, we'll guide you through easy at-home steps to troubleshoot your MTD outdoor power equipment from the comfort of your own garage. Holding the spark plug boot close to the engine to check for spark isn’t a reliable test because a bad coil can produce a spark in open air but fail when the cylinder is under compression. The most common causes are in the ignition (for example, a bad ignition coil) or fuel system (for example, a clogged fuel filter). Carburetion that's too small will stifle an engine and won't allow high revs, where real horsepower is made. Weak Battery. First you will have to remove the spark plug boot. Sounds like you sanded the coil poles, that should not have an dramatic effect on the spark. Does anyone know if these are prone to this type of intermittent failure as they get older (13 years)? Is there some way to diagnose this other than stick a screwdriver in the sparkplug wire to see if there's a visible spark?. If there is no spark, this indicates that the spark plug is defective and should be replaced. For reference, see our spark plug gap chart below, this chart converts metric measurements to standard. - Secure large alligator clip end of spark tester to good engine ground. Spark Arrestor: A spark can exit the exhaust port of a small gas engine, potentially starting a fire on nearby combustibles. Small-Engine Diagnostics by small gasoline engines need a minimum of 85 psi cylinder pressure on the compression stroke to start and run properly. It has a center electrode encased in a protective. If you get a weak spark then that is usually a sign the source coil is weak and not providing enough power for a good spark if the plug coil is good. Now, Holley EFI products power these cars and are dominating the performance world. To determine if the spark plug is defective, use a spark plug tester. Spark weak. I'm having ignition spark problems that I can't seem to figure out. With the countless expensive parts and tweaks we do to get the most out of our little Chinese 2-stroke motors it is easy to overlook the spark plug even though nothing you do will help with a crappy spark. The spark plug loads the coil when it is in a compressed mixture of air and fuel. I have set coil gap at. If the engine has a distributorless ignition, the ignition coils must be disabled to prevent them from firing. I could see that the spark at the points was a strong, steady blue for the right cylinder, but barely visible and throwing occasional yellow sparks on the left. Insert the spark plug lead on one end of a spark tester and attach the tester's alligator clip to ground, such as an engine bolt Place the equipment stop switch control in the OFF or STOP position. Place the sparkplug wire onto the sparkplug but do not install the spark plug into the cylinder, leave it dangling loose. Engine and spark plug manufacturers publish generic charts containing information about the characteristic appearance of spark plugs after being subjected to various normal and abnormal conditions. Possible Causes: This condition commonly occurs when gasoline contains too much lead; however, because spark plugs are changed frequently in racing applications, lead fouling has become less common. I'm having ignition spark problems that I can't seem to figure out. when i pull out the jumper wire and try to start , i get a little faint spark. In other words, the output to the plugs was directly tied to the speed of the reluctor. - Turn the engine over with the ignition switch at the helm and observe the spark tester. You will get nowhere with standard sockets unless it is simplest of simple small engines with easy to access plugs. If you have spark, the tool will show. -Missed explosions may result from a weak battery. i have put a jumper wire in the pig tail tat goes to another auxillary switch, not the main on/off switch. If the spark is yellow and weak, or there is no spark then the first thing to do is try a new spark plug. If your spark is weak and orange in color, replace the ignition coil. Remove the spark plug, and ground the "hex" part of the plug to a bare metal part of the engine. Nor is there a Spark EV prototype at the main engineering and vehicle-production complex in Bupyeong, where GM Korea is headquartered. On engines that don't have that access, you need to be a little more creative. Small-Engine Diagnostics by small gasoline engines need a minimum of 85 psi cylinder pressure on the compression stroke to start and run properly. If any one of these isn’t there, you aren’t going anywhere. Spark Plug Gap setting is important for proper engine operation. To set the spark plug gap correctly, you need to use a spark plug gap tool. When working on small engines, it's important that you use good judgement and take safety precautions. Here is another odd thing about my cruiser it is a 1973 with the original F engine. Kawasaki FH680D weak spark I have a Kawasaki FH680D-ES04-R that backfired and now it will not start. The most common way of checking your ignition coil is to use an in-line spark tester. More and more, it seems that knowledge which once was common, is passing into legend and obscurity, and model engines are no exception. - Turn the engine over with the ignition switch at the helm and observe the spark tester. Ignite small mower engines with replacement spark plugs. This system works by wiring a float into the ignition system: if the float is too low, the ignition circuit is cut, which prevents the spark plug from firing. A spark plug is a fairly simple device. Holding the spark plug boot close to the engine to check for spark isn't a reliable test because a bad coil can produce a spark in open air but fail when the cylinder is under compression. 2 Fluke Corporation Troubleshooting Outboard Motor Magneto Ignitions If the plug(s) are fouled with carbon and/or oil, several things could be wrong: The spark to the plug(s) is weak or nonexistent, the spark plug heat range is too cold, or the engine has been run for long periods of time at low speeds possibly with an incorrect fuel or. Three fundamental things can happen: a bad fuel mix, lack of compression or lack of spark.