425 rebuild or repower?

[buckshot721]

Ok I pulled out the 425 for it's grass cutting duties, ran great no problem till I turned on the deck. Stalled a couple of times(never did that before) finally got it to run. Ran it through some grass, engine started to bog down. Did not stall but to slow to cut with. Ran back into the shop, checked carb and the simple stuff. Even the gearbox on the deck nothing. Still bogged down, checked compression 170 on the left 80 on the right. Wet check is the same numbers. I'm thinking valves, not a head gasket. So with 500 hrs on the engine, yes it has the plastic cam gear according to my engine number. It still starts and runs good but not for mowing! So the question is rebuild or repower. Stated reading up on the repower kits some like them don't. I'm keeping the tractor till the wheels fall off, my wife does not like cutting with the x485. Thought about doing just a valve job but the mech at JD dealer said it would soon start burning oil, due to wear on other parts.

 

[TimS]

How about looking for a donor tractor with a blown transaxle or other major damage, but an OK motor? You could do the swap and then part out the rest of it. There were lots of these tractors built, so parts should sell pretty easily.

What doesn't your wife like about the other tractor for mowing?

Tim

 

[buckshot721]

I thought about a donor tractor, but can't seem to find any in my area of Michigan. The one I did find the engine was pulled and could not here it run. It looked like it was setting under water for a year. I'll have to ask my my wife why she does not like the 485. (It keeps her off so I can run it!)

 

[beenthere]

If me, I'd invest in a rebuild. There is a lot of tractor left in the 425 for years to come. A bit disappointing that the engine needs re-work at those low hours, but time takes its toll too. (unfortunately !!)

I've a 425 and would rebuild the engine if/when it may be needed. I also have the X485 and understand perfectly well why there is preference to the 425
I don't like the poorer mowing job the 54C deck does over the 54 on the 425.

Good luck with your decision.

 

[rsewill]

Run it some more. Your compression may come up a bit after sitting all winter. Make sure your deck is clean and the blades turn easily. Some will suggest using something like Seafoam to make sure it isn't something else like fuel. If it worked last fall it should still work now.

 

[Gittyup]

I'd rebuild it (if that is what it needs). Changing the cam gear isn't too bad. Getting the motor out of the tractor is most of the work. Once you have it out, it's pretty straight forward to pull the front off the block and change the cam, governer gear, oil pump gear, push rods, and some gaskets and orings. I did mine last year at a cost of about $500.

Have you adjusted the valves? I think 500 hours is when they say to do that for the first time. Very simple. Takes maybe 30 minutes tops.

The valve seals shouldn't be too hard either. Just remove the plugs and pressurize to hold the valves in place and relief pressure on the rocker arms and change them out. I haven't done this part. I bought the parts when I did my cam but decided to wait until its using oil.

 

[Rob50056]

My cam gear stripped out and Im thinking of a complete rebuild also.
1300 hours,doesnt smoke or burn oil so Im debating on whether to punch it and 20 thousandths or just ring and new bearings.
If I rebuild motor where are there other weak spots due to hours on rest of mower such as deck,tranny,etc...
I found a few complete rebuild kits for ~ 500.00 without cost of punching out.Im guessing 10-20.00 per cylinder and it's probably a good idea to get heads and block tested for cracks.

 

[RandyT]

I wish I could get cylinders bored for $20 per cylinder. I have to pay $80 per cylinder plus supplies. Last twin Kaw I had done cost me $168.

 

[crazyal]

Rob I would just change the cam and then do a compression check. You wouldn't need to fully assemble the engine to do the check. If the compression is good I would just put the engine back together and call it good. I think you'll start closing in on a grand for a full rebuild.

 

[Rob50056]

Rob I would just change the cam and then do a compression check. You wouldn't need to fully assemble the engine to do the check. If the compression is good I would just put the engine back together and call it good. I think you'll start closing in on a grand for a full rebuild.

That's a great idea!
I can't check compression now with gear stripped but after gear is replaced I can.

Didn't even occur to me!

It doesn't smoke or use any oil.
If it gets good compression should heads be pulled to inspect cylinder walls or valve work?