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PK., Small Engine Technician
Category: Small Engine
Satisfied Customers: 1052
Experience:  Retired Owner of a full service shop and national parts sales website.
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I have John Deere 425 that started missing and will not start

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I have John Deere 425 (Kawasaki twin OHV ) that started missing (while plowing drive) and will not re-start. Has always started right up over past two years, but hasn't been tested in cold weather. It's 10 degrees out today. I've tried everything short of replacing gas. (Cold start engine spray, fuel line anti freeze, cleaned carb, verified fuel flow.).... In 5 seconds of stead cranking the engine combusts once or twice - won't fire up
Hi my name is XXXXX XXXXX Have you check to see if you have a good spark at the plug ?
Customer: replied 7 years ago.
Yes - This is a Kawasaki twin - OHV engine with 950 hours on it. It's been a great running, problem free tractor over the two years that I have owned it. New spark plugs, new gas filter. Both plugs are getting spark - I checked by unscrewing them and connecting to metal - both are sparking. I also checked gas - it's flowing nicely to carb. I also dismantled cleaned carb (took off) - and cleaned jets best I could - nothing seems clogged.
Customer: replied 7 years ago.
Are you there?
Does it try to start ? Does it backfire ? or does it just turn over fast
Customer: replied 7 years ago.
The starter engages the flywheel and it cranks good (new Diehard battery and being jumped by car) . If I crank for about 5 -10 seconds straight I'll get a couple of combustions, like it's trying to fire up, but they just don't build into enough to actually get the engine running.

I'm trying to avoid overheating the starter
With it getting fuel and a good spark it should start for you . But I do beleive this engine has a timing belt in it and when they get worn out or slip it will cause this problem . If this helps please accept my answer .Thanks
Customer: replied 7 years ago.
Sorry, Delsley I don't think we're on the right track here - thank's for giving this a shot anyway.
Ok Sorry I could not help you . But to me from what you have said that is what it sounds like If you would please accept my answer . Are if you want i can opt out and try and let another expert help you.
Customer: replied 7 years ago.
This hasn't helped Desley.
Ok I will opt out and try and let one of the other experts help. Thanks Delsley

Hi I'll try and help you out.


Do you have a compression gauge? This would be something worth checking.


Does this have a heater or a wrap or is it someplace where it can be warmed up?


If the compression is good, then I would check the flywheel key. The key controls your ignition timing preset and it's not at all unusual for one to shear and cause the problem you're experiencing.


The fact that it won't hit on ether tells us to look past the fuel system for the time being and look at the other two systems necessary for combustion, compression and ignition. A compression check will give an idea as to the sealing ability of the engine, the rings and valves. Checking the flywheel key will verify that the ignition which you've already checked is being delivered at the right time.


This is where I would start in the shop with the symptoms you describe.


If the engine pops loudly through the exhaust or wheezes back through the carburetor that might indicate a problem with a valve, but generally on a twin it will only be on one cylinder. It's possible that the cold is preventing good sealing by the rings. 950 hours isn't an awful lot of hours on a quality engine like a Kawasaki, but there could be enough wear to loosen things up a little with the cold. But again, it's a twin so you would expect only one cylinder to act up. If the flywheel key has sheared, that will affect the timing to both cylinders. So if you feel that neither cylinder is performing, the key would be the first thing to check.


Let me know if you can check these things and what you get. Thanks, PK.



Customer: replied 7 years ago.
Well, I've already learned what the problem is from another source, but I do owe you credit for focusing on compression. Apparently, these Kawasakin twins were built with a plastic (!) cam shaft gear which also connects with the water pump. They are prone to breaking at around 400 hours. I confirmed the problem by removing the valve cover on one of the cyliners and checking for movement while cranking - got nothing, no movement, no compression. Also, when problem first occurred and I tried to restart engine I heard a whirring starter motor -only -like sound - as if flywheel wasn't engaging and flywheel seemed stuck. Eventually (perhaps after moving tractor) the starter began to consitently engage flywheel again. Should I be looking for any additional problems (other than broken camshaft gear)

Admittedly, and in hindsight, Delsley wasn't too far off the mark after all -although there's no timing belt involved, the problem and effect is similar.

There's no real problems to look for that I can think of. You are at the point where a 300 hr service should be done, if it's been done regularly. This would include pulling the heads and cleaning the carbon off and I believe Kawasaki suggests lapping the valves every 300 hours. Since you have a problem with the cam gear you might take the opportunity to go ahead and freshen the engine up with rings and a cylinder hone, but that's entirely optional.


As for the starter, I'd pull it off and check it out. It may have a worn gear or the pinion clutch might be wearing out.


I haven't had a water-cooled Kawasaki in the shop yet. I've owned a number of the air-cooled engines and had them on commercial mowers and really loved them. Good power and I don't think I ever had a serious problem with one.

PK., Small Engine Technician
Category: Small Engine
Satisfied Customers: 1052
Experience: Retired Owner of a full service shop and national parts sales website.
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