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.

1M05 · Apr 4, 2020

The head looked really surprised when I told it it was being replaced with a new one!

Here is where it was cracked:

And now the long wait for parts

California · Apr 4, 2020

Any idea what caused so much lost metal?

Rust? Pre-ignition? Other?

1M05 · Apr 5, 2020

I'm assuming because there was no flapper valve on the exhaust, it sat with water in it at some point. The rear cylinder is worse than the front one and I assume pre-ignition would be the same in both cylinders. I'll be sure to time the new injector pump when I put it back together.

winston1 · Apr 5, 2020

Do the liners look any thing similar to the head? Seems to me if it was only rust from water standing they too would have a similar look. Wondering if running with leaking head or head gasket for extended time wouldn't cause that look? :confused3:

1M05 · Apr 5, 2020

The cylinders looked fine. I guess it is possible someone changed the head gasket at some point but it wasn't leaking when I tore it down.

Jtullis13 · Apr 16, 2020

I was going to ask the same question that Winston did. Just curious because you may want to replace those liners, however it does appear that you know what you are doing.

1M05 · Apr 25, 2020

Got a good amount of stuff done on the tractor today. Got the new head installed, rocker arms on and valves adjusted including the compression release, valve cover on, drained the fuel tank and ran all new fuel lines and return lines, new water pump installed, new coolant hoses on, got the oil pan back on, and exhaust back on. Now just waiting for the new injector pump to get here so I can get it on and timed and then put the radiator and battery back in and get it running.

Andy1969 · Apr 26, 2020

1M05 said:
Got a good amount of stuff done on the tractor today. Got the new head installed, rocker arms on and valves adjusted including the compression release, valve cover on, drained the fuel tank and ran all new fuel lines and return lines, new water pump installed, new coolant hoses on, got the oil pan back on, and exhaust back on. Now just waiting for the new injector pump to get here so I can get it on and timed and then put the radiator and battery back in and get it running.

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Great progress! Let us know when you get it done and how you like it when you get to use it.

Jtullis13 · Apr 27, 2020

Dang you have been busy!! Show us a some final pictures and for sure let us know how it runs.

1M05 · May 1, 2020

I got the injector pump installed and timed.

This is how it should look when you are done adding or removing shims. The top mark is TDC, the bottom mark is the injection timing mark.

The hard part is getting this clip in after you are done pulling the pump in and out a few time to add or remove shims.

I got it all together and it runs!

But then I found an oil leak. The head had a flaw in the casting on the valve cover gasket surface so they welded it up to add metal and ground it down with a hand grinder. I pulled the valve cover back off and installed another gasket with some RTV in that spot but it still leaks. I'll have to pull it off again tomorrow. I wish I had known it would be a problem before I installed the head as I have a mill and could have milled the surface flat. After I took the valve cover back off, I could feel the surface is high in one spot and low in another.

1M05 · May 3, 2020

I got the oil leak fixed with some RTV. I hooked the rototiller back up to it and tested it out. It runs great! More power than it's ever had. Rototilled three gardens. This tractor should outlast me now.