M939 intermittent no-start?

[Alaskaboy]

I have a no start issue that only occurs once in a while. It will crank but not start then if i wait a few minutes and try again it starts fine. Sometimes i have to try it several times other times just once. Anyone know what i need to look for?

 

[Trailboss]

May be loosing fuel prime. Is it worse the longer it sits before you try to start it? Assuming NHC250 engine looking at your title.

 

[Scar59]

Sounds more like a M939A2, the 6CTA 8.3 has lots of issues with loss of starting fuel prime. NHC250 will start with just a whiff of diesel.

 

[swbradley1]

Sounds more like a M939A2, the 6CTA 8.3 has lots of issues with loss of starting fuel prime. NHC250 will start with just a wiff of diesel.

If by whiff you mean 15 seconds of cranking then yes, mine starts right up?



I'd say prime loss as well.

 

[Scar59]

If by whiff you mean 15 seconds of cranking then yes, mine starts right up?



I'd say prime loss as well.

SW
-15 seconds is a long time, all my 250s fire up w/i a couple of seconds of starter engagement. Even my ol' 813 rolls smoke in 3 seconds.

 

[98G]

I've had NH250 that would lose prime and require considerable cranking after sitting. If it hadn't sat it would start within half a second.

Is your IP leaking right around the accelerator pivot?

 

[Alaskaboy]

I was thinking losing prime the first time it happened but when i tried to pump the primer it was solid wouldn't even take one pump then the only way to get the pump handle in to lock it is to have the engine running. It is the NHC 250. It acts like it is getting no fuel then a minute later it will start before it even turns over one revolution. Sometimes it will happen within minutes of shutting down, other times it has been sitting for a few hours or days even. But most of the time it starts no matter how long it sat. Could the fuel solenoid be sticking?

 

[Floridianson]

Yes it could be the shut down solenoid. I always bypass that first thing if I have a no smoke no start problem with my 250's.