Loss of Power in YM1700

[Martin Fox]

Hi All - Until recently I my YM1700 has run just fine. Then today,
(pretty hot out) after running around for about 15 minutes I suffered a loss of power and stalling out. There was smoke coming out of the crankcase vent tube and after unscrewing the oil reservoir cap I noticed the oil was quite smoky. The radiator was hot of course, but not overflowing, coolant level was OK as well. I don't have a lot of experience with liquid-cooled or diesel engines, can someone give me a bit of advice on getting to the bottom of this problem? Thanks in advance!

Martin

 

[HoyeTractor]

Welcome to the board! You mentioned the temp... do you think it overheated? Did the temp light come on? Does it start back up now?

Aaron
Parts@HoyeTractor.com
(940)592-0181

 

[Martin Fox]

Thanks for replying Aaron. It seemed like it was overheating, I'll have to double check on the light because it was very bright out and I couldn't really tell if it was on or not. Essentially the tractor was running, then started to run a bit rough and begin to stall, then it started spewing smoke from the plastic tube coming from the oil crankcase at which point I turned it off. The tractor will start fine, but does this after about 5 minutes. At the moment I have removed the radiator to clean the fins and flush the coolant. I also suspect that the coolant may have been too strong a mixture - based on the color it was not diluted enough. I am also considering putting on one of your add-on water pumps, is there anything else that jumps out at you that I should check? Thank you very much for the help, I really appreciate it!

Martin

 

[LMTC]

Get it checked out by someone competent, or you may well add damage to damage. If you have overheated there is a fair chance you have damaged the head gasket at a minimum. If you can't see the warning lights on your dash tape a cardboard shade or something above them. They're there for a reason and if you can't tell if it's on or not, you'd better come up with a solution. Just a few minutes of overheating can cause serious engine damage. Coolant in an OEM 1700 (no pump) should NEVER exceed 30% glycol, and even less in warm weather IMO. A good dealer explains all this to a customer. The fact that you didn't even know what the blend is is a poor statement of maintenance. You should know. A tester is cheap.

I truly hope you have minimal damage, but the operator has to take accountability for using the machine. I would not consider spending the money on a pump until you know what damage has been done. Seriously---if it overheated, you're in a situation where damage could be limited or significant. Find someone with the capability to properly diagnose and repair and let them have at it. Good luck.

 

[Martin Fox]

Thanks LMTC, for the sobering advice. I suppose we all have to learn somehow, I just hope it was a close call and not a ruined engine!

Martin

 

[mark777]

...........spewing smoke from the plastic tube coming from the oil crankcase at which point I turned it off. The tractor will start fine, but does this after about 5 minutes.....

Martin

What color is the smoke and is it confined to the breather tube only?? Does the exhaust stack smoke look normal? The color of the smoke is relative to diagnosing the symptoms you've posted. If the smoke is gray-white it usually indicates a mixture of exhaust gasses and vaporized coolant. If it's blue-black it may indicate something broken, like pistons, rings or cylinder wall
(or liner).

I may be wrong (and someone correct me please), but if the exhaust tube smoke is white-ish in color, you may have a blown head gasket or cracked cylinder head.

Let us know, don't run it for very long and I'm sure there are many people here than can help you find the exact problem before you attempt a tear down.

Good luck,

Mark

 

[Martin Fox]

Hi Mark - Thanks very much for the help. These problems are much less depressing when there are nice people out there to give advice. The smoke is coming from the crankcase breather only, the exhaust appears to be normal. Engine will run smoothly with no visible issues for about 5 minutes and then run rough and smoke through the breather. Seems like engine was starting to overheat, although coolant/radiator was not overly hot. There was no steam, and no white smoke anywhere. Another thing I noticed was that on the overflow tube on the radiator there is no reservoir bottle. Based on the information I have been able to find, it seems there should be one, even though there is no obvious place it should be mounted. So basically there is just the radiator- no tank. Again, I really appreciate the help.

Martin

 

[Gizmo36]

reservoir bottle gose on the front of the radiator .

COOLING_SYSTEM: Yanmar Tractor Parts

 

[Martin Fox]

Update - I disassembled the radiator and cleaned it, then flushed it, then added a 30% glycol coolant mix. I then added a coolant recovery tank. Tractor runs smoothly, sounds good, exhaust from stack is good, does not overheat/ run rough etc. The only issue now is that there is still smoke coming from the crankcase breather tube, as well as a drip of dirty oil. Upon closer inspection, the smoke seems to be more whitish, like a bit of vaporized coolant? I plan on taking it to a diesel mechanic when I can, but does this sound like a leaky head gasket?

Martin

 

[mark777]

Martin,

Something is causing positive pressure to the crankcase. I am not sure but IMHO combustion is bypassing the exhaust valves and forcing exhaust passed the piston rings.

You can make one last test that will indicate a blown head gasket or cracks between intake and exhaust valves on the head. With the radiator full and the cap removed try a cold start-up first time of the day. Watch closely for several minutes (during engine warm up) while the tractor is at idle. Look for small bubbles rising at the neck of the radiator top. If thery're there...at minimum you have a blown head gasket.

If you are confident of your mechanical skills you have to make the choice of tearing it down, remove the head and gasket and examine everything including rotating the engine to view cylinder walls.

As LMTC indicated, taking it to a shop now (before touching it with a wrench) will provide the opportunity for the mechanic to see and diagnose the problem while the tractor is still operational. I hope it's a simple head or gasket problem.

Mark