Yanmar L70 excessive smoke

[Dieseldan45]

Hello all, new here! Anyone familiar with Yanmar single cylinder diesels?

I recently won a Yanmar L70EE off a government auction site, that I was wanting to swap on to a logsplitter. It starts, idles and runs great, however it never stops smoking even when warm. It doesn't appear to be using oil, smoke is a dark grey color with slight blueish hue.

I've tried so far:
-Different fuels, on-road and off-road diesel from different gas stations.
-Different oils, Rotella 10w30 and 15w40.
-New air filter.
-Cleaning the old injector, then replacing it with a new injector and shim.
-Removing and adding shims to the injection pump, supposed to change timing according to the manual.

Nothing has helped, it can sit there running for an hour, smoking away. It seems to me as if it is over-fueling, but I'm not sure what to try next at this point.

Any help is appreciated, thanks!

*In the pics the smoke appears more blue, think its my camera filter. In real life it is more gray.*

 

[duffer]

If it's a blueish gray smoke, I believe it is indicative of oil getting into the cylinders and burning, as opposed to excessive fuel. Excessive fuel is usually black smoke.

You may have a bad set of piston rings, which wouldn't surprise me at a gov't auction

 

[California]

If it's a blueish gray smoke, I believe it is indicative of oil getting into the cylinders

You may have a bad set of piston rings, which wouldn't surprise me at a gov't auction

Yes. It may have been removed from service specifically because it was smoking. Maybe it had been overheated?

Is this run often enough to notice the amount of oil consumption?

My experience buying stuff cheap in unknown condition is I generally win the gamble but not always. Some turn out to need work, like this!

 

[bmaverick]

Hello all, new here! Anyone familiar with Yanmar single cylinder diesels?

I recently won a Yanmar L70EE off a government auction site, that I was wanting to swap on to a logsplitter. It starts, idles and runs great, however it never stops smoking even when warm. It doesn't appear to be using oil, smoke is a dark grey color with slight blueish hue.

I've tried so far:
-Different fuels, on-road and off-road diesel from different gas stations.
-Different oils, Rotella 10w30 and 15w40.
-New air filter.
-Cleaning the old injector, then replacing it with a new injector and shim.
-Removing and adding shims to the injection pump, supposed to change timing according to the manual.

Nothing has helped, it can sit there running for an hour, smoking away. It seems to me as if it is over-fueling, but I'm not sure what to try next at this point.

Any help is appreciated, thanks!

*In the pics the smoke appears more blue, think its my camera filter. In real life it is more gray.*

There is a SPECIAL thread just for your Yanmar engines located here. The guys here are deeply knowledgeable to help you out.

Forum for air cooled diesel engines and clones

i have been doing some reading of a service manual and am now wondering if my L100 has had the injector pump replaced with the wrong one at some point, according to the manual there are two types, D and S, D being generator spec with max and min rpm of 3800 and 1200 compared to S spec of just...

www.tractorbynet.com

The area of your posting deals with Yanmar tractors and excavators.

 

[bmaverick]

Hello all, new here! Anyone familiar with Yanmar single cylinder diesels?

I recently won a Yanmar L70EE off a government auction site, that I was wanting to swap on to a logsplitter. It starts, idles and runs great, however it never stops smoking even when warm. It doesn't appear to be using oil, smoke is a dark grey color with slight blueish hue.

I've tried so far:
-Different fuels, on-road and off-road diesel from different gas stations.
-Different oils, Rotella 10w30 and 15w40.
-New air filter.
-Cleaning the old injector, then replacing it with a new injector and shim.
-Removing and adding shims to the injection pump, supposed to change timing according to the manual.

Nothing has helped, it can sit there running for an hour, smoking away. It seems to me as if it is over-fueling, but I'm not sure what to try next at this point.

Any help is appreciated, thanks!

*In the pics the smoke appears more blue, think its my camera filter. In real life it is more gray.*

The 10W30 is the way to go. In the thread I posted, there are manuals for the L70 Series too.

To clean the fuel delivery system, Seafoam works great. Old soot and deposits take a long time to burn off. Seafoam greatly assists in getting that out. And Seafoam is originally for diesel engines before it became popular for gas engines.

 

[Dieseldan45]

Yes. It may have been removed from service specifically because it was smoking. Maybe it had been overheated?

Is this run often enough to notice the amount of oil consumption?

My experience buying stuff cheap in unknown condition is I generally win the gamble but not always. Some turn out to need work, like this!

Very possible, it could need a new set of rings. Although I have not ran it very long, maybe 2-3 hours total, the oil level seems the same.

But yup, this is my first, and probably last online Gov. auction. Not only was I blindsided by the shipping cost for this little motor, (Mainly because the warehouse wouldn't take it off the skid it was bolted to), It arrived missing parts/bolts and smoking. Lesson learned, I guess!

 

[Dieseldan45]

The 10W30 is the way to go. In the thread I posted, there are manuals for the L70 Series too.

To clean the fuel delivery system, Seafoam works great. Old soot and deposits take a long time to burn off. Seafoam greatly assists in getting that out. And Seafoam is originally for diesel engines before it became popular for gas engines.

Ah, did not see that thread, lots of info in there. Is there a way to move this to that section, or just post in there as well?

I did run some Seafoam through it, before I swapped out the injector. Seemed to help a little bit.

Thanks

 

[California]

Ah, did not see that thread, lots of info in there. Is there a way to move this to that section, or just post in there as well?

I did run some Seafoam through it, before I swapped out the injector. Seemed to help a little bit.

Thanks

Seriously, repeat your inquiry in the thread where all the single-cylinder Yanmar owners are posting. There are several real experts there. In contrast to this general Yanmar forum.

Here's the latest post in that thread. Start from there. You will likely get replies like 'Here's how I remedied that same issue ...':

Forum for air cooled diesel engines and clones

The generator is a Powerchief, powered by a generic 186f chinese 10hp diesel (Yanmar copy), I rebuilt it because it suffered compression loss due to piston land failure which resulted from excessive carbon build up in the combustion chamber and eventual failure of the PCV system. Who ever...

www.tractorbynet.com

 

[90cummins]

I’ve repaired a couple of the mil-surplus L70’s that had issues similar to yours. The problem was caused by wet stacking then a long period of setting unused.
The moisture in the oil corroded the injection pump cam lobe which in turn affects the injection event.
remove the injection pump & lifter and inspect the cam lobe for pitting.
If the cam looks good then it’s possible the needle bearing on the end of the camshaft is failing.
Remove the oil filter screen & check it for magnetic particles.
These engines are very easy to disassemble.
To remove PTO cover remove valve cover to remove push rods then remove injection pump. Remove screws from PTO cover & work cover off. Cam is easily removed at this point. Piston is also easily removed.
90cummins