Help! - Trouble with Yanmar YM1700

[GoVols]

I've had a grey market YM1700 for a little better than a year. It has run great - I've used a 4 ft. bushhog, leveled a new driveway with a box blade, and pulled a small disc when sowing a new lawn. Then, last weekend, things started deteriorating quickly. It began to overheat while bushhogging fairly thin grass. I would bring it back to idle for a short period of time, then shut it down to let it cool off. It got to where I couldn't go more than 5 - 10 minutes without it overheating. I've been troubleshooting with all of the suggestions I've seen on this forum - drained the radiator and rinsed it out, used compressed air to clean the outside of the radiator, started the tractor cold with the radiator cap off to check for bubbles (indication of blown head gasket - didn't see any bubbles), replaced the radiator cap, changed the coolant mixture to 67% distilled water, 33% anti-freeze. Nothing seems to help. Oh, and I replaced the temperature sensor that feeds the overtemp light when I first bought the tractor (the original switch got to staying on all the time even when the tractor was cold - once I replaced it, everything worked fine). The worst thing is that in the midst of all this troubleshooting, the tractor seems to be smoking worse, it sounds different at the exhaust pipe (like there's more volume of flow??), and it's consuming more oil. I don't think I've overheated it, because I've been diligent about shutting it down and letting it cool down every time the light has come on. The tractor was basically running great one weekend, then went to crap the next. Am I looking at a major overhaul here, or am I missing something simple?

 

[bruce1966us]

First of all I would have the radiator clened by a professional. Should only costs around $60 bucks.

 

[ALABAMA_KID]

Did you check the fan and belt?
Can you see light through the radiator fins?
Did you see any sludge in the radiator?
Just trying to think with you.

Good luck.

 

[HGM]

GoVols,
The overheating is alarming in its own. However, the exhaust thing bothers me. The overheat may be secondary. You mentioned more flow, is it possible that its just louder due to a restriction? You didnt mention if you checked the air cleaner either. If it has a restricted air filter, it will loose power, sound louder and consume oil. Another idea might be to run the engine with the dipsick or oil fill cap off to check for blow by. Having not doen this on my tractor, I cant really tell you what is normal, but I wouldnt expect much. Someone else might be able to chime in here....

A little more invasive, I would recomend a compression test and maybe runnn it with the exhaust manifold off to see it one cyl smokes more than the other and or if it runs better. One caution though, I wouldnt run it long with the manifold off as it wouldnt dissipate heat properly.

Keep us posted, we can keep thinking...Good luck.

 

[pruntyc]

I found on mine, that the radiator still had some junk in the fins. I got it wet and kept it that way for a while, then took a hose with a high pressure end on it. Blowed the water back through it, from the fan side, you have to keep moving the fan, to do it. But a lot more stuff came out of it. It still was getting hot, a lot. So I looked at the cap, it looked good, but went down and bought a new one, 13# I think it is, and that stopped it from overheating. You might just have a cap problem to. After all these are about 30 years old and the cap may be the one that came with it new.

 

[GoVols]

I really appreciate all of the ideas y'all have supplied. I've worked a little harder on cleaning up the radiator, and I have tried a new radiator cap. It was hard to tell if I've done any good this evening, however, because it has turned off cold here in middle Tennessee. The different exhaust noise and increased smoking is still there, however, so I'm going to try removing the muffler as someone suggested on a private reply, and see if the dirt dobbers got to it this summer. I will probably also change out the air filter as someone else suggested, although it's got only about 40 hours on it, and It doesn't seem to be very dirty. A couple of other questions if anyone is still interested:
1. What sort of oil are you guys running in the YM1700's? Right now I've got straight 30W HD oil in mine.
2. I've read somewhere that the injector pump getting out of time can cause the YM1700 to overheat and smoke excessively. Do y'all know anything else about this? What would cause one to get out of time? How big of a deal is it to get one set back to the proper timing?
Thanks again.

 

[Eddie]

Is the smoke blue or black??


ROLL TIDE

 

[Jagmandave]

Pull the dipstick, is it overfull?

 

[arthr31]

hi there,
we never heard back about this.. but, i have a similar situation (lots more smoke) and the only thing I can find is that there is oil in the exhaust. When I took the down pipe (or up) exhaust off the manifold i found lots of oil like residue... What could this be? I don't seem to be burning any more oil so I'm not sure where the build up is coming from or if this is even oil... Any ideas? I'm fearing that this might be an indicator of rings....?!?

Thanks. -Art
p.s. this is on the 1601 gray with 62 hrs on the rebuild.. whatever that might mean?!? /forums/images/graemlins/shocked.gif

 

[Soundguy]

Goey black oily stuff in the exhaust pipe is sometimes 'slobber'.. That is.. some soot.. maybee some water.. and maybee some unburnt diesel...

An old diesel that slobbers a little.. I wouldn't worry about...

Soundguy