debugging poor starting diesel engine

This machine has been poorly maintained. And, in the process of getting it down off the mountain and onto a trailer, it went out of control and turned over into the woods. (this was reported on this forum a few weeks back) So, my first action is changing all fluids and filters.

Today I changed the crankcase oil and filter, the big hydraulic filter, and the main fuel filter. I'll be getting air filters this week.

Currently, it is very hard to start, but does eventually run. I hold the glow plug button for about 10 secs, and crank. Very quickly it starts to hit on about 2 cylinders I'd guess. Smoke and unburned diesel vapor come from the exhaust.

I can tell it is nearly running because if I turn the throttle down to stop, There is a large change in the sound.

If I crank long enough, it eventually catches and runs great when it does. I think a clogged injector is ruled out- it really sounds like it is hitting on all 4. I see some minor blueish smoke while it warms up, then the exhaust looks good.

I don't know much about debugging a diesel engine. Does it sound like maybe I have one or more bad glow plugs?

Now, bear in mind that it is pretty cold. Today was a balmy 34 degrees at the warmest, but it has been sub freezing mostly.

I plan to put some diesel 911 in the tank, and replace the primary fuel filter which is a simple inline filter. By the way, I have read that you never use starting ether on a glow plug engine. My Case back hoe requires it in the winter, and says so in the manual. This kubota engine warns agains it.

Any tips on debugging a hard-to-start diesel engine would be appreciated.

Overhaul solved the problem. Now it starts right up with no ether.

Mark

Is it tricky to check compression on a diesel? Do you just pull the injectors one by one? Aren't those things seriously torqued in (and you can't use a socket)?

Thanks

Never worried about torqueing injectors. I do use a new copper washer anytime I remove one for any reason.

Best way to tell if a cylinder is working is to crack the fuel line to the injector. Under the nut (at the injector) it will fist fist fist fuel out under the nut every time the pump hits that cylinder and the rpm's will drop off noticeably. Retightening the nut restores the smoothness and rpm's. That is how you know if that cylinder is working for you or again you.

Mark

I think that some of the fuel in the tank is old- it was largely empty when I got it, but I added 5 gals of fresh. The manual talks about summer mix and winter mix diesel. It suggests adding 10% kero for cold weather. Maybe this is just a fuel issue.