JD 425

[tirekicker]

WHAT WOULD CAUSE AN OTHERWISE GOOD RUNNING JD 425 TO SOMETIMES SPIN OVER 3/4 OF A TURN AND COME TO A DEAD STOP. ENGINE HAS 180 LBS. COMPRESSION ON BOTH CYLINDERS, AT LEAST WHEN IT IS NOT ACTING UP. NO SIGN OF BAD HEAD GASKETS OR CARBON BUILD UP. GOOD BATTERY, BAD STARTER? THANKS.

 

[Bob]

You mean it does this while CRANKING with the starter?

Sounds like you may need to set the valves.

 

[tirekicker]

Yes, It does this while cranking. I don"t think that it is the valves because the compression is right in spec. thanks

 

[Bob]

The reason I suggested checking the valves is that the "tappet" clearance on these OHV enignes is very small, and (on MANY small engines, I'm NOT sure about the KAW), if the gap is too great the automatic compression release won't function.

So, unless someone comes along with a better idea, find out what the "spec's" are, and try setting the valves.

 

[jd b puller]

This is one of the few lawn mowers that DON'T have a compression release. You said that the compression was 180 but it won't turn all the way over. So it must be able to freely rotate, which would eliminate any kind of mechanical binding, right? The valves [b:e1e233c75a]may [/b:e1e233c75a]need adjusted, but that shouldn't prevent him from cranking the engine.

Make sure you have good contact points for the starter, battery, solenoid, etc. Does it do this ALL the time, or just sometimes?

What's the serial number on your engine, is it before or after 149283? The engine, not the tractor.

Other possibilities - camshaft has chipped tooth, flyheel key sheared/partially sheared enough to throw off timing.

 

[t1]

Check the joints on the drive shaft for wear or damage. A Bad joint can cause it to occassionally lock up.

Kawasaki lists the MAXIMUM compression for the engine as 170 lbs. Your is a little high at 180.

Don"t think its a stuck valve, but doesn"t hurt to check. Usually a stuck valve doesn"t stop the engine from turning as the push rod just bends. They"re skinnier than a pencil. Valve clearance is 0.010 for both intake and exhaust.

Keep in mind this engine has a plastic cam shaft gear, that WILL break and strip teeth someday. Since it sounds like yours runs, its probably not your current problem, but keep it in mind. The replacement is all steel. Doesn"t usually cause the engine to lock up, they just stop running. You can confrim that problem by removing the valve covers and seeing if the valves work as you crank the engine. If not, stripped gear teeth.

I have a complete service manual for the tractor, and engine, but its HUGE. About 50 MB for tractor manual, I can email copies of parts of it if you need them.

The engine manual is about 4MB, put the tractor manual covers the engine and its parts in greater detail.

 

[jd b puller]

t1, you might want to read that Tech manual again. MINIMUM compression on both the 425 and the 445 is 170. Normally if the engine is running good it's 180-200.

 

[t1]

My apologies, you're correct.

coffee first, then lookup stuff and reply. I got to remember that.

 

[Anonymous-0]

.010 For both valves. Could have a starter issue. I have had some of these taking on water in a cylinder and create a hydro lock situation too. Just a thought.

 

[deanop]

is it flooding alot when it sits..? gas in the oil? gas in cylinders could cause it...

 

[fredmich]

Hey I know I'm late on this but I just seen your post and was wondering if you tried taking the plugs out and see if the condition still exists. This would determine if you have a flooded cylinder (gas or anti-freeze). Perhaps by now you have found the problem and could post back to let us know. Thanks...Fred