Yanmar L100

I got a diesel generator for free. I was told on another forum that it was a Chinese Knock Off of a Yanmar L100. Based on pics from an L100 parts breakdown it looks to be really close.

The previous owner originally told me that he had dropped a bolt into the engine and did not have the time to deal with getting it out because basically it would have to be torn all the way down.



After further discussion I found out that it wasn't a bolt but part of the fuel pump assembly that had fallen in and that the motor had been turned over after that and it went about a quarter rotation then locked up.

I fished around through the oil drain and from the hole left when the fuel pump was removed and did get a couple small pieces of metal so I know that there is some damage inside.

I finally got the generator part off and now am ready to dear into the engine itself. My question is: Do I just remove the bolts and pull off the side cover and take a look or is there more to it? Is stuff going to come falling out if I don't have it oriented a certain way?

 

Hello rockwellb!

Welcome to Doityourself.com.

Tip the engine a bit so that the side cover you are removing is facing up a bit. That way, when you remove the cover, the parts should stay in their places. This also reduces the amount of oil dripping that will occur when you open the engine. Do you have a diagram similar to the one you posted, but which shows the engine internal parts? This would be helpful in case you do have a broken internal part.

 

Thanks Cheese

How much is "a bit"? 10deg, 20deg, 30 deg...

No i do not have a better diagram that contains the internals.

 

Well, the more you tilt it, the more gravity will assist in holding the parts in place. 90 degrees wouldn't be too much, but 45 might not be to little. Just be easy with it and when you get the cover loose and begin to open it, take a flashlight and look to see if anything is being pulled out with it. Don't worry too much, it's not a big deal if it does.

I don't know if I have a diagram anywhere of that engine or not. Doubtful. I am not very familiar with that particular engine, but I'll see if I can find a diagram.

 

I went with the 90deg option.

Got it apart and it's not good. First pic is a piece that was laying in the bottom of the engine. The second pic is where it broke off . Looks like it is part of the block and the only way to even hope of getting it running would be to weld the piece back on as long as it is not bent too.

There was another piece that looks like it rides on the crankshaft and slides up and down through the space created by the piece that broke off and the block that pushes up on the fuel pump.

Is there a 12VDC pump that would produce enough pressure to push the injector?

 

Is it bent/twisted? Kind of looks like it in the pic. At this point, you have nothing to lose, so I would suggest either taking it to a machine shop and let them weld it back if it's where they can. I don't think this piece would normally be under very much stress, and if it were welded back carefully, it could be smoothed enough to allow it to function again. Even if you had to work with sandpaper and a dremel tool to make a good fit, it shouldn't be critical if it's a little off or has some scratches and gouges here and there. It's a sliding part and just needs to be held in place.

 

I haven't had a chance to get it to a welder yet but showed it to someone else that came by the house and he said it looked like pot metal to him. Makes since since it is a Chinese knock off. If so it looks like it can't be welded.

Cheese,
Do you have a source to procure the main engine block assembly ( 114310-01020 ) ? Just shoot me a PM

 

It's aluminum and can be welded, depending on the experience/ability of the welder.

I don't have any supplier for yanmar parts, sorry. I would go through a dealer or the generator manufacturer just like you would.

 

I ended up taking the engine apart and found that part of the engine that the fuel pump actuator rides up and down broke. Took forever to find someone who could and would weld it back in place. Now I am ready to put it back together and it looks like the crank that pushes the fuel pump actuator needs to be in a specific orientation in relation to the piston so that it pumps fuel at the correct time. Anyone have any info on when the pump should pump fuel?

When piston is at the bottom, half way up, 3/4 of the way up, ......?

 

I wish I could tell you, but I am not familiar enough with that engine and I don't think I have a manual for it. If I do, it is packed away in storage. I do know the pump is timed to deliver fuel at TDC, so if you rotate the engine in the normal direction of rotation and crack the injector line, it should squirt fuel at TDC. There are likely marks to align to make this more precise.