So, has anyone had the problem I am having on this Kawasaki engine? I have been troubleshooting to find out why it is backfiring. You will see that I have reset the valves, put on a ne head gasket, and checked the flywheel key. In a previous video, I put on a new coil, new ignitor, and spark plug boot and finaly good a good stron spark. It is still backfiring! Let me know what you think. I would appreciate some helpful comments and feedback.
I had the same problem with same mower. I did everything you did. Just for the heck of it I put a new carburetor on it and I’ll be damn it started right up and stop backfiring. Maybe I got lucky but I thought it would be easy and try it for the heck of it . Have a few of those cheap Chinese carburetors from eBay laying around new in box. Hopefully you get it. when you had the valve cover off did you turn the engine over slowly by hand to see if each valve moved about the same lift. If they are not moving about the same it could be the lobe on the camshaft is worn
@@SmallEngineDIY Have you set both the intake and exhaust valves to 6 thou? Reading online I'm seeing someone has fixed this by setting the ignition coil to .3mm I like head scratchers, especially if we all learn something in the end. I'm curious as to what the fix will be.
Thanks for the video bought one yesterday of course it had no hood. It was raining on the way home now the symptoms are the same I have a fan on it let it dry out. We will see Update fan did the trick runs great
Hopefully this will help you. RU-vid: "Why your lawn mower or generator backfires/misfires and how to fix." EASY. The presenter gives a great explanation. Back to the valves, he said it is 100% of the time the Valves also check the flywheel key, which also goes to the valves for timing. I have the same problem with my DR Mower with a Kawasaki FC 420V. The presenter said "Try tapping the intake valve with a soft mallet" to break loose the buildup on the valve. The additives in the gasoline build up around the Intake Valve. Hopefully this will resolve both of our problems since they appear to be the same. If it is the exhaust valve, it will normally have a bent stem.
Did you use lapping compound on the valves? It sounded like the intake valve wasn’t closing properly. Also when you take the head off you can put water in the intake and exhaust ports and check for leaks around the valves. It won’t hurt anything, if you’re worried about using water blast it out with some carburetor cleaner or something when you get done.
Wow...I'm in the process of tuning and fixing up my JD GT275 with the FC540V. New hood and muffler. Then two days ago it did the same thing yours is doing...including a LOUD backfire. It actually ran well enough to make it around the block, but I could feel puffs of air coming out of the air filter inlet. I thought it needed a valve adjustment. Turned out it's a broken intake valve spring.
@@clutch5sp989 remove the valve cover and look for a broken valve spring. Easy to confirm or exclude this cause. I replaced the spring myself. I videoed the process, just haven’t had time to edit and post.
@@jedi_mapperp4073 OK...today I pulled the plug and checked having NO SPARK. Put a new plug in and had spark. WoW...nothing is supposed to be that easy to fix. I have never seen a plug go bad and not work.
@@jedi_mapperp4073 Also...when it cools off a little more here in TX, I'll pull the cover & check clearances. That and many other mech projects to tackle.
I have a Craftsman with a Kohler Pro 16hp CV16S and when it's on idle it purrs like a kitten. Run it up to speed and it sounds like a jalopy! Keyway is perfect. Can't adjust valves. Pushrods are perfect. Switching out w a new carb and spark plug and we'll see how that goes.
I just had the same issue with my 25hp twin kawasaki, it felt like the timing was wrong but it cant be, the issue is that because the ignition timing is on the crank and not the cam meaning that the spark is on compression and a wasted spark on exhaust stroke, there for if the coil does not have enough spark it will not fire on compression but will fire on exhaust which has a fuel mixture in it because it did not fire on compression there for bang out exhaust and carby.
That makes the most sense. I have put on a new plug, but not a new coil. But does that also apply if the back fire is thru the carb? Because that would mean that the intake valve has to be open. And I know that my valves are operating correctly. Yet I still have the back fire thru the carb, big time.
Weak magneto coil. Spark outside cylinder is different than under pressure. That's why it works when you use a spark plug with a lower resistance rating.
Leak down test, spark test, plug test, flywheel magnetic in correct place to fire on compression, valve movements, fuel pump test and starting fluid test
i have 2 mowers with the same engine , and 3 with the slightly larger fc540v engines . they're really particular about the plug . i've had them that would spark real well with plug out of engine , but wouldn't when plug was installed . swapped the plug from one that ran , and it would start then . usually though , the igniter has gone bad .
I think you're on the right track with timing. I agree with what someone else said to watch the valves to get any hints on possible cam issues. If it's not the lobes then maybe the gear not lining up properly? But how does that become misaligned after running properly? Maybe broken teeth on cam gear? Definitely puzzling. Keep us posted
Check your spark putting in line tester check your spark for it sounds like your coil is going out or is gone out also use a little hit of fogging oil or starting fluid it has to have done something probably the coil went out that's why it died or is going out it's a weak spark I just have to have fire and gas and it will run
I know this is an old post, but did you ever find the problem? I have a Kawasaki fc540v doing the exact same thing. Had it running after changing igniter, fuel pump, carb, fuel shutoff solenoid, spark plug, fuel lines. Sat idle for a week, went to start and won’t fire and backfires very loudly.
I went through all the same things you have including lapping in the valves to no aval. I had spark and discounted that as the problem. I finally installed new coil and igniter and it solved the problem. would it be possible that the igniter even though new is still not functioning correctly?
Definitely a timing issue. If the valves are not sticking and the valve springs are good, then maybe a camshaft to crank misalignment. Seems that would be quite odd from the way it just quit. That it fires out both the intake and the exhaust indicates either the timing keeps changing or both valves are sticky and are taking to long to close. Try some carb or parts cleaner in the valve guides if you think they are sticky. Make sure both springs are not broken. Other possibility is the timing gears are slipping. Those would be the mechanical things to look at. If I understand right there are no points. That means it must have a cam or crankshaft position sensor to control the timing, which then activates the ICM. Could be a bad sensor or loose screw/wire, or bad ICM. Those darn electronic ignition modules and sensors can be a pain. Give me the old points and condenser any day, much easier to tell if something is good or bad. I thought is was either a head gasket or slipped flywheel key. Had the latter happen to me once. I would start with the sensor and ICM, make sure it has ground good. I gather you have checked the timing and the spark after it quit running. Let us know how it goes. Would really like to see what the fix is. One other thing to check is that the battery voltage is not low, and the charging system is working. Some electronics do not work very well when the voltage is just a tad low. Maybe try running it with a charger hooked up, or a boost from a running vehicle, or good battery.
My 170 does this and I just feather the choke down and it fires up. So maybe full choke first few cycles and then when it starts puffing I back it off and it fires up. I’m no small engine mechanic but it’s been like this for 5 years since I bought it. Runs every summer like a top lol.
My FC540V just recently did this. I'm still working on it but I do know if I pour just a little gas straight into the carburator, it will run for a few seconds, making me think it's not a timing issue.
@@philliphall5198Sorry, didn't really think anyone read my comment. It turned out I had water in the gas. Pretty sure it was from the ethanol gas. I would much prefer to run straight gas in my mower but unfortunately there aren't any gas stations near me that sell straight gas. Anyways, I drained all of the old gas out and put in fresh and it ran just fine. Because of the issue I was having, I took the carb apart and cleaned it which it really needed.
@@SmallEngineDIYI cut with it almost every weekend 1 to 1/1/2 acres. I thought of getting another JD sometime soon but I have wondered if there is anything comparable to this one today. I am in limbo. :)
Here's what I think it is myself. It's one of three/3 things valve sticking& not seating properly.,or the lifters need readjusted again. It could be from A blower head gasket aswell to.
This john deere i have backfires so loud when it turns too much and i hate it i had a craftsman older but it started every time first try even after a long chrismas
I got the same problem with my kohler courage 20 but mines isn't back firing. It's just spinning and then the starter acts like it wants to hang up and then the fuse blows
This happened to me I bought the lawn mower the breather cover was removed the the oil had water in it. I could get it to run but it kept backfiring ended up just switching the engine