Approximate cost of DIY 425 Kawasaki engine rebuild,piston,rings,bearings,etc..

[Rob50056]

I made the mistake of letting someone use the machine I maintain and they mowed leaves 2 feet thick,then ran machine until it quit.
Oil filter clogged up,oil looked like it had mercury in it,so I need to go through the whole engine.It has so much blow back,I can fill a 8 ounce cup in seconds with pvc tube.Govenor has to be bypassed just to keep engine from surging.
I won稚 know the full extent of damage but I just replaced plastic cam gear with metal cam gear kit and got 190-210 lbs per cylinder.
Of course now the person I let use machine thinks it could be something simple and inexpensive,but they just didn稚 realize mowers are not leaf mulchers and to be operated in dust.
Even with a new filter on it it sucked up fine dusty particles and it took hours to clean grime out of carb.

 

[Zebrafive]

A JD gasket set is $131
A JD .020 oversized piston set (two pistons, rings, clips for the piston pin) is $205. That is if you need to rebore oversized. Then you need to factor in the cost of having the cylinders bored oversized.
The only bearings are on the crank ends, I doubt they are bad???
What about the oil pump?, water pump, governor?

Maybe just a stuck or broken ring??? Or burnt valve???

It will need a tear down to determine what repairs are needed then the cost.

There may be a cheaper source of parts than JD. Maybe Kawasaki?? EBay?? Used engine??

Sorry for your bad luck. How many hours on the engine?

 

[beenthere]

Think, as said in another thread, that you are falsely blaming "someone" for misuse of your 425. Not the leaves that caused your problem, IMO. In 20+ years of mulching leaves with the 425's. Handled deep leaves well and didn't plug up the oil filter. Something failed, but not due to the leaf issue. IMO

Sounds like you did the cam replacement, and maybe will do the needed engine repair now. Wish you well with that. I often think if I was in the same fix with my several engines, how I'd go about repair as I'd like to think I could do it myself (with the help of the TBN experts here).

Bottom line, don't loan your machine out.

 

[prichard]

I can't see how overloading could clog oil filter. Could someone explain that?

 

[IH3444]

Personally I would pull the engine heads off, mic the cylinders down to find out taper. If more than 0.002 I would consider a rebore. It's your call. Too much taper causes the rings to flex a lot and many cause them to break. If the taper is acceptable to you, hone carefully with proper crosshatch pattern. You maybe able to get away with just a hand honeing with a scotch brite pad. Install pistons with new rings. It may take a little while for the rings to seat to a freshly honed, non-bored cylinder. Use a light break in oil for the first hour, 0-20w regular dino, non-synthetic. Dump it, and change to fresh oil, 10w-30w. Pay close attention to temp gauge, and don't allow to over heat. May use some oil for first 50 hours, check oil level frequenly. I personally would do a valve job, with new valves. I'm not a fan of reground valves on my own equipment. As soon as you grind down past the surface hardening the under lying metal gets soft quick. Check valve guides for excessive play, most likely they are OK. New valve seals, and lap them in with fine compound. Clean everything perfectly before reassembly. Decarbonize the heads, and look for any cracks between the valve seats. Also check lower rod bearing clearance. A good quality upper freshen up maybe all you need. Best of Luck, IH3444

 

[Rob50056]

Personally I would pull the engine heads off, mic the cylinders down to find out taper. If more than 0.002 I would consider a rebore. It's your call. Too much taper causes the rings to flex a lot and many cause them to break. If the taper is acceptable to you, hone carefully with proper crosshatch pattern. You maybe able to get away with just a hand honeing with a scotch brite pad. Install pistons with new rings. It may take a little while for the rings to seat to a freshly honed, non-bored cylinder. Use a light break in oil for the first hour, 0-20w regular dino, non-synthetic. Dump it, and change to fresh oil, 10w-30w. Pay close attention to temp gauge, and don't allow to over heat. May use some oil for first 50 hours, check oil level frequenly. I personally would do a valve job, with new valves. I'm not a fan of reground valves on my own equipment. As soon as you grind down past the surface hardening the under lying metal gets soft quick. Check valve guides for excessive play, most likely they are OK. New valve seals, and lap them in with fine compound. Clean everything perfectly before reassembly. Decarbonize the heads, and look for any cracks between the valve seats. Also check lower rod bearing clearance. A good quality upper freshen up maybe all you need. Best of Luck, IH3444

Thanks!
I知 looking at Repower engines as an option but I still need to tear down Kawasaki and see damage.
If it痴 not too bad I値l punch it out and rebuild.One side compression dropped to 70-80 while the other is 170-190 strong.
Never loan a mower out!