[djacobs]

Hello wfm members,

I have a Jd 400 that I bought and restored. The tractor has a 23 hp (582)kohler replacement engine (mfg april 2000) with about 450 running hours. The engine starts and runs good, no smoke or oil leaks. However, the engine overheats, backfires sometimes at shutoff, and has used some oil even though it does not smoke or leak oil. What can cause these issues and how should I go about fixing the engine?

 

[grandpajay]

Hi Danny,
I'd start with richening the high speed jet on the carburetor and idling the motor for a minute before shut down. Almost all the small engines in my experience used a starting setting of about 2 turns open on the carb settings and maybe adjust a little lean from there. The K582 surprised me and used an initial setting of 3 turns on the high speed needle. What are the symptoms of the overheat condition? Jay

 

[djacobs]

Jay,

Thanks for your response. The engine appears to get excessively hot to the touch (crankcase, oil filler tube, etc.) after only five minutes or so of run time. Although the engine does not smoke or leak any oil, I've had to add oil (half quart or more) after about thirty minutes run time (full throttle with deck engaged). I believe this may be a result of evaporation due to the excessive heat. What do you think?

 

[tommyhawk]

In addition to checking the carb. setting, points condition and proper gap, air flow should be checked out. Are all the engine shrouds in place? Muffler shielding? Belly screen in place and clean? Foam seals in all areas that keeps air flow coming from cooler area under the tractor, rather than hot engine air?
Mice love to build nests in the engine shrouding and can cause air flow blockage and fires, so check it out.
Last I don't think oil will evaporate as water does, but it will turn into sludge when overheated. Hope you find the problem soon.

tommyhawk

 

[djacobs]

Tom,

Thank you for your input. I will drain the oil to make certain there is no sludge. There is no belly screen on this tractor ( I have a 318 that has one). I looked on the JD parts web but they didn't show a belly screen for the 400. I would like to know if its required, I would certainly get one if they are availble. Also, all the engine tin and shrouds are in place and clean. Thank it might be something else?

 

[tommyhawk]

What I called a belly screen, JD calls a cover. It is listed with the driveshaft, believe it or not.
If it's missing, and you aren't collecting a bunch of grass clippings inside the engine shroud, chances are that is not the culprit anyway. NLA from Deere but someone may have a good used one to sell from a parts tractor.

You might want to go through JD parts, or your parts manual if you're lucky enough to have one, to see what other parts might be missing.
I don't use the side covers on my 317 in the summer, but that's a different story.
Have you already checked the points and richened the carb. mixture?

tommyhawk

 

[djacobs]

Tom,

Thank you very much for your important info. I believe that the "cover tin" you're refering to is missing. I've decided to pull the engine and check everything including the fuel mixture setting, ignition, and cooling train. I know this engine is not worn out with only 450 running hours and I'm determined to correct the over heating. I will post again to let you know the results.

 

[69project]

If it is getting hot and there are not any obstructions/grass etc then I would think either the timing is off or maybe you need to adjust the valves possibly. Just a guess.

 

[djacobs]

Thanks guys,

I set the high speed jet three turns out and the engine doesn't backfire (at shut-off) anymore. As far as I can tell it does not run hot anymore but it does smoke just a little ( I posted last week that it didn't smoke any but I was mistaken). I can see where oil is being sucked into the carburetor and this makes me wonder if the breather valve (located on the governor) might not be working. Any suggestions will be appreciated.