Need Help with 350 Cummins Diesel Engine

[BigDawg99]

on my Fishing vessel...I have a 350 Cummins Diesel Engine on it..It has 1471 Hrs on the engine..last 2 months i have been having a starting problem..i go and push the button first thing in the morning and it takes a while before it gets fuel and starts up..Once it starts..the Boat Runs Excellent and when shut off..it will start with the first push on the button..and the engine will run great...can someone tell me what is going on with this motor..i want to get it fixed and have it winterized and ready for the spring season...

[DeepFrz]

What is the temperature? Do you have a block heater installed?

[captain58sailin]

At first blush, it would appear you might have an air leak in a fuel line, or something is allowing the fuel to drain back to your tanks, have you recently changed or drained your racor filter housing? If you did not replace the "O" ring on the top and tighten it down well, or if you drained the bowl and didn't get the spigot tight, then you could possibly be sucking air from there. That is just a rough guess. It would be my first level of investigation.

[leftbrainstuff]

Sounds like a combustion charge temp issue. Try glow plugs, intake air heater...

[Mark1977]

Cummins are notoriously known for hard starts in the cold, but it's not that cold here yet. Probably an air leek somewhere.

[klem]

What model/injection system are they?

I would disagree that cummins are hard to start in the cold. I have a few 6B's that I routinely start without their grid heaters at below freezing with almost no cranking time.

These engines do not have glow plugs, they occasionally have grid heaters but that should not be the problem this time of year.

Is the engine cranking over quickly? Do you still have full power? Can you notice any difference in how it runs?

My first suspicion would be a small air leak in the fuel system as suggested above. To test this, manually turn on/pump the lift pump for a while before trying to start the engine. If the engine starts right away, there is most likely an air leak. There are other possibilities as to what is wrong but this is likely the culprit and it is easy to test. Finding the leak is a bit harder though.

Good luck.

[Seahunter]

Air leak in fuel return line (low pressure) or mechanical fuel pump bellows has leak. If you have an electric fuel pump, make sure it's functioning.

[DRS]

B models on the highway side were notorious for bad fuel lift pumps as well. Try bleeding the air at the fuel pump and at the injector lines.

[BigDawg99]

i know i have a leak on my return fuel line rail...Just seen it the other day..once i change the fuel rail and ill bleed the system..Hopefully that will clear the air..I am running the C series cummins diesel engine..

[CharlieCobra]

Yeah, I always thought my Cummins 350 was cold natured until I bought a rig with a Detroit V92 in it....