Yanmar L100 need some help with starting

[Skinny]

Hey guys

I have an L100 engine I'm trying to get running. It's in a gen with a 1000 hours. The symptom is it will crank, come up to the compression stroke, then stop. Sometimes it will kick back and blow grayish smoke from the intake like it backfired.

So far:

-Put some new 6 gauge battery cables on it with a 525 CCA battery
-New starter with the ground directly on one of the starter bolts
-Set valve lash
-Bled all the injection system
-Tough to tell the pump timing but it appears to be pretty close to 15 degrees advanced
-I have a good spray pattern from the injector
-I pulled the head and it didn't have a lot of carbon buildup but I cleaned it up anyway
- Slammed it all back together and same symptom

So here is the weird part. When I cleaned it up it will crank through no issue even without using the compression release. If I give it a small hit of starting fluid or if I push on the governor arm just a hair to get it to start fueling it stops dead in it's track. Then it will do that every time I crank it. Makes a full rotation then stops.

Once in awhile I can get it to fire maybe 2 or 3 times and then it stops.

I was thinking that maybe the timing is too far advanced. Or maybe I have another bum starter.

I am lost on this one for sure....

 

[Dieselmeister]

Hey guys

I have an L100 engine I'm trying to get running. It's in a gen with a 1000 hours. The symptom is it will crank, come up to the compression stroke, then stop. Sometimes it will kick back and blow grayish smoke from the intake like it backfired.

The fact that it will kick back and blow smoke from the intake make me think it's a timing problem.

Does this engine look like it has been pulled apart before, and reassembled wrong? (Camshaft gear misalignment).

Verify your TDC, and look at the valve timing. That will quickly show you any cam gear misalignment.
My manual shows 13 deg +/-1 BTDC for the injection timing.

 

[FarmingSmallKubota]

Do not use starting fluid on these engines. Also make sure when you pulled the injection pump you got everything lined back up on the Governor. and that the injection pump is moving freely

 

[Skinny]

I got this engine as a big question mark. I cannot verify if it's been apart but it doesn't look like it has been. That is my next guess is time to come apart and verify timing of everything.

The pump appears to have shims under it so I don't think it has been messed with.

One of my concerns is that the engine is fine and that the starter isn't strong enough to get it to soin through the compression stroke. I used a set of cables for an air cooled standby which are 6 gauge.

The battery is big enough but I wonder if it just simply gets hot and immediately doesn't have the nuts to soin through.

I may try a second battery with another set of cables to eliminate that.

 

[FarmingSmallKubota]

You never have said what Generator set this is, but i have a Non military Yanmar brand Generator with a Yanmar L100 and with decompression valve and recoil rope starts as easy as it does with the electric start

 

[Skinny]

You never have said what Generator set this is, but i have a Non military Yanmar brand Generator with a Yanmar L100 and with decompression valve and recoil rope starts as easy as it does with the electric start

It's a Generac XD5000

I pull it by hand using the decomp lever and I can't pull it through once it hits TDC when the lever kicks. Now I'm not a big guy but you'd think I could at least pull it through.

That's when it pops and smokes through the intake like it almost combusted but since it didn't go through the engine rolled back and it blows through the intake.