JD 425 AWS stalling

SteveD425 · Sep 7, 2020

New here... I have a 1994 425 AWS that was on open-ended loan to me for the past several years by my father in law. He passed away a couple years ago and I have inherited this and several other pieces of equipment. He was always surprised it hadn't died yet. It finally may have. It has always burned some oil and required new plugs at the beginning of summer. Last summer I ended up replacing the plugs twice. Runs good until the plugs get fouled, then starts stalling. Put new ones in and it keeps going until the next time they get too fouled.

This summer, I was able to mow for about two hours before the plugs fouled. I replaced them and got about 45 more minutes. The attached pic is the latest plugs - with about an hour of total use on them.

Question is, do I do a complete rebuild of the engine, or just the rings (or something else). I am reasonably mechanically inclined, and just finished replacing the steering control valve on this tractor. I really like the 425, and would like to keep it around and running.

Thanks,
Steve

Roadworthy · Sep 7, 2020

If you do the rings you should probably do the valves as well. Since you'll have to pull the oil pan to remove the pistons give some thought to rod and main bearings as well. If replacing rings you should make use of a ridge reamer and glaze breaker. Although that's not quite the same as a total overhaul you've hit the high points, leaving water pump, timing chain, and timing gears for later as well as cam and lifters.

tomplum · Sep 7, 2020

What I wouldn't do is go crazy and tear it down right away. Horizontals Kawasaki's can have issues with the breather not draining well back into the crankcase due to a blocked passage. So look for oil in the breather hose or something that leaks enough air into the crankcase that messes with the flow of things and prohibits the engine from running at a vacuum. A leaking front cover as example. A shop would determine this with a manometer and do a basic ring test to get a feel for this before tear down.

Richard001 · Sep 10, 2020

Steve,

Welcome to TBN
:welcome:

I agree with Tom, plus have you done a compression check?

Also are you sure that you have the correct plugs? They look like they are to cold for your engine.

SteveD425 · Sep 12, 2020

Learning a lot in short order... Ran some SeaFoam top engine cleaner through it today at the suggestion of a coworker. Seems to have helped - plugs looked better afterwards. While checking the plugs, one of the spark plug boots pulled off from the wire - that connection was substantially corroded. Cleaned up the cap and cut the wire shorter and reconnected them. Works, but the plug wire is stretched very tight. And yes... as it turns out, the plugs are wrong. I've always replaced like for like so they've been the wrong type for years. Off to pick up new ones now.

SteveD425 · Sep 19, 2020

I replaced the plugs with the correct ones. Seemed to have no effect. I read in other posts that too much oil could cause surging. The oil level was high so I drained some off. Wasn't terribly high, but wanted to rule that out as well. I also checked the compression - left side was 190, right side was 180. Still within spec.

I ran it for a while without the air filter just to see if anything changed. Ran well for a few minutes, then start to stall. If I closed the choke for a second or two it would recover and then go back to running well when I opened the choke again. Lather, rinse, repeat for about 20 minutes. Then it wanted to stall, but didn't recover as before - ran but surged dramatically with the choke closed and would try to stall if I opened it. And then it went back to running normally again. It looks like there is a little bit of oil coming out of the breather tube. not sure if that's normal or not.

And that's probably all I'll get to do with it this weekend. Other projects. Eventually if nothing else works, I will pull the engine and make it one of my winter projects.

Richard001 · Sep 20, 2020

Steve,

From your first post:

This summer, I was able to mow for about two hours before the plugs fouled. I replaced them and got about 45 more minutes. The attached pic is the latest plugs - with about an hour of total use on them.

From your post #6:

I ran it for a while without the air filter just to see if anything changed. Ran well for a few minutes, then start to stall. If I closed the choke for a second or two it would recover and then go back to running well when I opened the choke again. Lather, rinse, repeat for about 20 minutes. Then it wanted to stall, but didn't recover as before - ran but surged dramatically with the choke closed and would try to stall if I opened it. And then it went back to running normally again.

What you are describing in your first post and your #6 post, are two different issues.

Typically when you have to pull on the choke to keep the engine running, you have a fuel problem, or more precisely, a lack of fuel. So for problem as stated in post #6, I would suggest a thorough carb cleaning.

I don't see any correlation between the two problems. Fix the carb and then see what happens. Also make sure that your fuel tank gas cap vent is not plugged.

Richard