Tamd 40b cold start

Hello all,


I have finally made back into the water after 6 years. One of the engines have an issues starting on cold starts everything is fine after running for 4-5 minutes and restarts all day long just fine. On the first start after warming the glow plugs for 20 sec or so it attempts to start and runs on a couple cylinders and stalls, after several attempts of the same start runs rough stalls as the temp increases it smoothes out and runs on all 6, It starts right up after you get past this. It will start and run fine all day or as many times as you start the engine. I have checked the glow plugs and they all glow. It seems as if there are only 3-4 cylinders firing when this happens and as I try to restart it seems to spin over the same amount each time before starting and running on those 3-4 cylinders, It does this on every cold start only. While it is going thru the warm up process it runs like an old V8 engine that may have been flooded and clears up. Any Ideas???

It sounds like a fuel problem. First check to see that you do not have an air leak. Your injector pump maybe leaking down. Bleed all injectors when the engine is cold. See if this clears the problem.

You may also have an injector or two that is stuck. I would pull the injectors and have them tested at a Bosch shop. They should be able to test them for free.

Thank you Glen, sounds like a great place to start. I will let you know what I find out!

I agree with Glen - get the injectors checked. Next thought would be the lift pump. If it gets a small air leak it might give similar symptoms.

Had the injectors checked, same problem exist. All injectors were in good condition. Runs like it is missing on cold start for seconds and clears up.

Maybe an air leak or compression problem. I suspect a small air leak. Search this board for the procedure to attach a clear tube in the return line. Look for bubbles.

Glen,
Are you talking about the return line that goes across all the injectors and back to the injection pump, also why would you think a compression problem? It runs awesome after the first start and is never low on oil. Or would that be something to monitor?
Thank for the advise.
Bryan

That may be the problem! I think the return line should go back to the tank. Air gets trapped in that line when it sits awhile. If you return your fuel to the pump, it can cause problems.
i was thinking of compression in relation to temperature. When things warm up and expand, it can cause issues. Your engine does not show any signs of low compression. However it shows signs of air in system. I would double check the fuel return line ( the one across the top of injectors ). Let it flow into a bucket. Make sure no air is getting into pump. Engine should crank.

Thank you Glen I will check all the lines, when I had the engines out to redo the engine bays I also replaced the lines. I did not run the boat for about 6 years while redoing the boat. I did not run it much when I purchased it but makes sense. When you said let it drain into a bucket did you mean while it's running as far as the over flow of fuel not needed. I believe there is a return line off the injector pump back to the tank because there was two lines I replaced. One I guess is the delivery to the pump and the other is the return. I will check this weekend. Thank you again!