Yanmar 2GM starting problem

[Airframe]

Doing a cold start on my Yanmar 2GM requires that I use the decompression lever on the #2 cyl while it's turning over. Once it is running fine on the #1 cyl I flipped the decompression lever and away it goes. It will not do a cold start on 2 cyls, but after it is warmed up it will start fine on 2 cyls.

Here is what I have done to so far:
- Removed the fuel injection pump and had it checked.
- Injectors removed and checked
- Starter replaced.
- I have tried bleeding the fuel system prior to starting and this doesn't help.

Help!!!!!

 

[Tim R.]

Have you checked your glow plugs? Sounds like the glow plug in #2 is dead.

 

[sailaway78]

Hard starting

The Yanmar 2 GM, I don't think uses glow plugs. I know a 2QM doesn't and a 3GM doesn't. Not sure I understand the problem though. Does it turn over too slow to start with both of the cylinders having compression. I recently had a similar problem with a 3GM. Slow to spin over, particularly when cold. Intermittent other times. Finally solved the problem by removing, cleaning and tightening every battery connection in the boat. Positive, negative, selector switch, and starter terminal. Problem solved. If it is spinning slowly, and your batteries are hot, and the starter is good, this is more than likely your problem. Takes some time, but worth the effort.

 

[Airframe]

Have you checked your glow plugs? Sounds like the glow plug in #2 is dead.

There are no Glow plugs

 

[Airframe]

The Yanmar 2 GM, I don't think uses glow plugs. I know a 2QM doesn't and a 3GM doesn't. Not sure I understand the problem though. Does it turn over too slow to start with both of the cylinders having compression. I recently had a similar problem with a 3GM. Slow to spin over, particularly when cold. Intermittent other times. Finally solved the problem by removing, cleaning and tightening every battery connection in the boat. Positive, negative, selector switch, and starter terminal. Problem solved. If it is spinning slowly, and your batteries are hot, and the starter is good, this is more than likely your problem. Takes some time, but worth the effort.

All connections cleaned and Starter replaced. I thought that was the problem also, ether connections were bad or stater was weak.

 

[Joseph Shirley]

You may be getting a large voltage drop from your battery to the starter. Is the wire getting hot?

Just another thought.

Joe s

 

[Tim R.]

There are no Glow plugs

Nevermind.

 

[Dalliance]

Here is a page from the Yanmar Service Manual for my 2GM. It kind of sounds like you have either a fuel injection problem or inadequate compression pressure. Hope this helps.

 

[Mike Holibar]

Have you tried opening the throttle. The 2GM and 3 HM I have owned both needed a good amount of fuel to fire up when cold - quite a common problem the mechanic told me. Another 2 GM I know of was hard starting after an injector pump overhaul. It transpired that the nut on top of the pump just under the fuel line was loose.

 

[Airframe]

Starting issue Solved

I completely stripted my Yanmar engine and I found the starting problem with it. When I pulled the #2 piston out the rings fell off. They were broken in about 3 pieces and also the piston was cracked. There was a no damage to the cyl liner or rod. Everything else seems fine with the engine. Waiting for parts to reassemble.

 

[Maine Sail]

I completely stripted my Yanmar engine and I found the starting problem with it. When I pulled the #2 piston out the rings fell off. They were broken in about 3 pieces and also the piston was cracked. There was a no damage to the cyl liner or rod. Everything else seems fine with the engine. Waiting for parts to reassemble.

Did you ever use starting fluid in this motor? This is exactly the type of failure that occurs when starting fluid is used in a diesel. Check the ring lands on the piston (the area of metal between rings) often times these crack and can also cause the rings to crack..

 

[Airframe]

Did you ever use starting fluid in this motor? This is exactly the type of failure that occurs when starting fluid is used in a diesel. Check the ring lands on the piston (the area of metal between rings) often times these crack and can also cause the rings to crack..

Never used starting fluid. Yes the ring lands are cracked and I'm replacing the piston.

 

[druid]

If it's not cranking over fast enough, the problem is not injectors, compression, etc (in fact, if compression was low it would turn over faster!). If you've replaced the starter, it's very likely a voltage problem - power is simply not getting to the starter. I'd use a voltmeter and check the voltage at the starter, and work back to find where it drops (could be the battery..).

If it's turning over fine but just not starting, it could be compression, but most likely it's just that this engine has no preheating (glow plugs). I have to crank my 2GM20F for at least 5-10 sec, then give it a LOT of throttle, to start it when cold.

druid

 

[Airframe]

Starting issue Solved

I finished rebuilding my Yanmar and started it, works great. It will be interesting to see how much more power it has next summer when it goes back in the water.