YM2000 hard starting cold

1M05 · Mar 29, 2020

I pulled my engine apart today to get to the bottom of the hard cold starting problem I've had since I bought it quite a while ago. Traced it down to low compression in the #1 (back) cylinder. Head gasket was fine but both valves were leaking in the #1 cylinder. Pulled the head apart to see what I needed and found both intake ports in both cylinders were cracked across the seats. Nothing a new head won't fix. I'm think this is not a common problem with these. Anyone else run into this?

thepumpguysc · Mar 30, 2020

It sounds as if u know what yer doin.. so u know that heat is usually the culprit..
Check Hoye & Fredricks for a head..
Good Luck

CoyPatton · Mar 30, 2020

1M05 said:
I pulled my engine apart today to get to the bottom of the hard cold starting problem I've had since I bought it quite a while ago. Traced it down to low compression in the #1 (back) cylinder. Head gasket was fine but both valves were leaking in the #1 cylinder. Pulled the head apart to see what I needed and found both intake ports in both cylinders were cracked across the seats. Nothing a new head won't fix. I'm think this is not a common problem with these. Anyone else run into this?

If it is just the seats (as you stated) for the valves that are cracked, consider taking your cylinder head to a machine shop and see if they can redo the head. I have to confess I have never taken apart my yanmar motor, but seats can often be replaced.

thepumpguysc · Mar 31, 2020

Yup.. seats replaced & cracks "stitched"..

Andy1969 · Mar 31, 2020

I just put my 2210 engine back together due to a previously leaking head gasket, which I temporarily fixed to get me through last summer by re-torquing. When I took the head to my local machine shop to have it gone through, the first thing he did while I was there was to look at the head visually very closely between the valves for cracks and didn't see anything. He also magnafluxed it later too as part of the normal checks for a rebuild and found nothing. He has been in this business all of his life and I have known him for over 30 years, and he told me that it is not uncommon to find these little Yanmars (and other brands) with cracks in those areas. And he also echoed what the pump guy above said, that it is usually caused from overheating due to a plugged radiator screen and not watching the temp light or gauge. So I got lucky and mine was in good shape so he just made it flat again to cure the leaky head gasket problem permanently and did a valve job to freshen things up. But again as the pump guy says, new seats and stitching up small cracks in the castings should be well within the wheelhouse of most good machine shops. Hope it works out for you and you don't need an entirely new head.

California · Mar 31, 2020

I had to replace the head on a 4 cylinder Isuzu Trooper and the new third-party head had a warranty conditional on putting in a new radiator at the same time, mandatory. I think most head problems start from reduced cooling ability. Particularly in these 40 year old models.

1M05 · Apr 1, 2020

Ordered a complete head from Hoye. I have a magnafluxer and seat grinder so I was going to order new valves and guides and grind the seats my self. Didn't need to get it out to find the cracks. I bought the tractor not running a few years ago. The previous owner had loaned it out to a buddy who ran it out of diesel. Not knowing about diesels, he simply refilled the tank and then cranked on it until the starter melted. I bought it with the starter removed and a bad radiator. I replaced the radiator and starter and started using it. Ran fine in the summer, hard to start in the winter. It has gotten worse over the years so I decided I was going to fix it. The cylinders look fine but the head looks like it sat for a long time with water in them and at one point and rusted. The combustion chambers are pitted bad! I took the injector pump to a diesel shop to be checked out. They called today and said one cylinder was not providing enough fuel and they could rebuild it for $550. Ordered a new pump for $350 from Hoye. I also got a new water pump even though the old one isn't leaking yet. I changed all cooling hoses when I replaced the radiator. Just waiting for parts to come in so I can put it back together.

Andy1969 · Apr 1, 2020

Yikes! Yeah that head looks pretty nasty. Did you buy the loaded head they have ready to drop in? That’s going to really freshen that engine up just in time for spring. Let us know how it goes once you get your parts.

1M05 · Apr 2, 2020

Andy1969 said:
Yikes! Yeah that head looks pretty nasty. Did you buy the loaded head they have ready to drop in? That’s going to really freshen that engine up just in time for spring. Let us know how it goes once you get your parts.

Yes. The loaded head. It needed valves and guides anyway.