Yanmar L100V Help Request

CallMeColt

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Wilson County, Texas
So, I got a renewed motivation to get this thing to run again.

Checked everything again. Then once more. Removed the head & everything looks good in there as well.

No way to pressure test but in the last week of reading things on people repairing these Yanmar L-series engines & the 186 type clones, the fact that I can't pull past the compression stroke means I'm okay.

I've narrowed it down to needing the lap & clean the valves & seats.

I also found a TON of very good information & manuals on this engine. The files are to large to upload unfortunately.

Will report back when I get the work done. Need to order some things.
 

snowtrac nome

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western alaska
A bunch of dredgers tried those to run suction dredges up here they found if they weren't able to get a proper load on them the valves would carbon up and the motor would do just what you described i would look at intake and exhaust chambers and see if they are restricted with carbon. On larger engines i have seen restricted mufflers do this to.
 

CallMeColt

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So, I spent a full day yesterday trying to get this thing running again with no luck.

Removed the whole top end & cleaned everything in a parts washer. Lapped the valves. Re-checked everything. No luck!

Disassembled the injector successfully this time. Cleaned the inside of it & tested. All was good. Still no difference in it running.

I'm at such a loss!
 

jeffhuey1n

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So, I spent a full day yesterday trying to get this thing running again with no luck.

Removed the whole top end & cleaned everything in a parts washer. Lapped the valves. Re-checked everything. No luck!

Disassembled the injector successfully this time. Cleaned the inside of it & tested. All was good. Still no difference in it running.

I'm at such a loss!

Kudos for your continuing efforts. Never let the machine know it’s kicking yer buns. I came across this link and maybe the information provided will help you. Keep digging. Wish you were closer, I’d love to dig into the problem. As they say (or at least used to) don’t give up the ship!
 

CallMeColt

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Thank you for the article but that is way past what I have already done. The injection pump & injector are working as they should.

To rule it out, I have tried 3 other injection pumps & had the same results.
 

jeffhuey1n

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CallMeColt

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Wilson County, Texas
You probably have this one as well. One problem I ran across, can’t remember what engine, where is was a crack in the metal inside the piston wall. You may have already covered this but run a compression check, if that’s even possible, and see if you are losing enough compression to fubar the start. If it isn’t that, I’m stumped.
I have no way to do a compression check because the needed adapter is next to impossible to find. But, the engine start & runs, just doesn't get up to speed.

Everything I have read on these small Yanmar engines, if you can't pull past the compression stroke that there's enough compression.

:(
 

jeffhuey1n

SMSgt, USAF (Ret.)
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I have no way to do a compression check because the needed adapter is next to impossible to find. But, the engine start & runs, just doesn't get up to speed.

Everything I have read on these small Yanmar engines, if you can't pull past the compression stroke that there's enough compression.

:(
Do you have a part number or description of the adapter?
 

CallMeColt

Active member
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Location
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Finally spent some more time on it now that I can do a compression test. Getting about 420 PSI. The manual says 460psi is the standard. Low limit of 365psi. These were done at 68 deg. It's probably 90 deg out, so that will make the psi drop. I'm within the limit on compression.

So, this leaves me at fuel timing. I really don't want to find & buy the needed tools for the fuel timing test so I may just try adding/removing shims of different types from the injection pump as that's how you adjust the timing anyways.

May get to it this evening & I will report back my results.
 

CallMeColt

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Wilson County, Texas
Well, the 4 combinations of the injection pump shims I had made no difference.

I noticed a bit of exhaust smoke coming out of the intake. Going to let the engine cool & check the valve clearance AGAIN.

I'm going to go through the TDC confirmation process as well. It's possible that somehow, the TDC marking on the flywheel is off & is making my valve adjustments incorrect.
 

jeffhuey1n

SMSgt, USAF (Ret.)
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Finally spent some more time on it now that I can do a compression test. Getting about 420 PSI. The manual says 460psi is the standard. Low limit of 365psi. These were done at 68 deg. It's probably 90 deg out, so that will make the psi drop. I'm within the limit on compression.

So, this leaves me at fuel timing. I really don't want to find & buy the needed tools for the fuel timing test so I may just try adding/removing shims of different types from the injection pump as that's how you adjust the timing anyways.

May get to it this evening & I will report back my results.
Good luck!
 

CallMeColt

Active member
361
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Location
Wilson County, Texas
Alright, so I went through the process to confirm TDC. According to my test, the TDC mark on the cooling fin was off by about 1/8 inch.. quite a bit. I marked it & adjusted everything off the new mark. Same issue... just chugs along & barley keeps running.

I really want to just toss it in the scrap bin.

It will cost me another ~$150 to get the tools to do the proper injection timing test. Honestly, I don't think that will even change anything. Usually if the timing for injection is off for some reason, it's only 1 small shim off. I tried that.

This is all on top of the fact that it did run perfectly fine & then didn't for no reason after re-wiring the key start.

It really makes no sense... I have compression, fuel, & air. It has to be an issue with timing but I'm just not finding it.

Might just shelf it again for a while.
 

jeffhuey1n

SMSgt, USAF (Ret.)
Steel Soldiers Supporter
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Location
Laramie County, Wyoming
Alright, so I went through the process to confirm TDC. According to my test, the TDC mark on the cooling fin was off by about 1/8 inch.. quite a bit. I marked it & adjusted everything off the new mark. Same issue... just chugs along & barley keeps running.

I really want to just toss it in the scrap bin.

It will cost me another ~$150 to get the tools to do the proper injection timing test. Honestly, I don't think that will even change anything. Usually if the timing for injection is off for some reason, it's only 1 small shim off. I tried that.

This is all on top of the fact that it did run perfectly fine & then didn't for no reason after re-wiring the key start.

It really makes no sense... I have compression, fuel, & air. It has to be an issue with timing but I'm just not finding it.

Might just shelf it again for a while.
You reworked the key start? Is the part new, used, NOS or the original part, just rewired?
 

CallMeColt

Active member
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Location
Wilson County, Texas
You reworked the key start? Is the part new, used, NOS or the original part, just rewired?
I replaced it with something that was close since I had no idea on a part number. I also did had to change the wiring. Found out the problem all along with that was that there was a diode in the starting circuit that rubbed through wire insulation under a shrink wrap. Had no idea the diode was there. Wasn't ab;e to find a wire diagram until way after the fact.

With all that said, that issue would have nothing to do with the engine running as it is. I solved the issue & everything ran fine for a number of hours & load tests.
 
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