Toyosha diesel question

[sbauerz28]

I have a diesel related question and I'm hoping someone may be able to point me in the right direction. I'm working on my neighbors tractor, a Simplicity 9518 with a Japanese Toyosha 18hp 3cyl diesel engine.

The problem is when it starts it seems that the front cylinder isn't firing. There's a lot of white smoke out the exhaust. When it starts to warm up you can hear the front cylinder start to fire, or "come in". As it continues to warm up, it will continue to "come in" and "go out". After it warms up the front cylinder seems to fire ok and the white smoke clears up, but it will continue to miss at full throttle.

When you crack the injector lines open with it running, the back and middle cylinder make a big change in how it runs and the front cylinder make hardly any change on how it runs. This is why I believe it's a problem isolated to the front cylinder. I turned all the injector lines around 180° and hooked up the injectors out of the engine. When cracking, they all seem to have a consistent spray pattern.

Just spent $250 the other week and had the injectors rebuild. It does run better, but it wasn't the main problem. Compression in all 3 cylinders is 375-400psi. When checking the valve lash the other night, I noticed that you can push the valves open with your fingers. Does this seem right?? I checked the engine manual I have for my D600 and it said spring pressure should be around 14 lbs. This just seems very light to me. I'm now leaning towards a valve float or valve hanging problem. If I can find a head gasket for this Japanese engine I may just pull the head to have a look.

My neighbor keeps telling me it's the injection pump, but it doesn't seem right to me. You can turn the pump up until it's rolling black smoke under any load. That tells me the pump has the ability to supply enough fuel. I should also mention it doesn't lose any coolant or run hot.