Community Forums

RanCarr · 06-19-2014, 05:03 AM

Quote:

Originally Posted by Murf2u

I'm very confused. In your first post you said it starts great when hot, but is tough to get started when cold.

Now you seem to be saying the opposite, it won't run when hot because the choke is still on.

Either way, I don't see how starting from inside panel or outside would affect the automatic choke operation.

Maybe I missed something.

Let me try and explain it a little better. When the gen' is cold the choke opens and she starts, but then the choke will not close. So she bogs down and stalls. But once he gets it running manually and it warms up for the day, it will start OK using the inside switch. So apparently the choke closes when it's already warmed up, or doesn't open at all. The problem he said is the choke will open, but once the gen' running, will not close.

ahicks · 06-19-2014, 05:50 AM

Thinking something is getting lost in translation here, but I think I get what's going on. First, a choke always closes to start a cold engine. Once started, the choke is supposed to open as the engine warms, allowing the warm engine to breath normally.

This one sounds like it's closing fine, but not opening quickly enough when the engine starts. Probably running really rough and blowing black smoke.

The choke needs to be adjusted. There's a bi-metallic spring inside, that opens and closes the choke as temperatures change. Whoever adjusted it last probably set it to close too tight, so it's not opening quickly enough. It should be set so it's barely closed when the engine is cold.

Depending on age/model, some have a vacuum pull off that helps open the choke when the engine starts. That pull off may not be doing it's job for whatever reason. That could be another adjustment, a broken vacuum line, whatever.

As far as being more specific, I haven't worked on one in 20 years. It would be easy if it were here in front of me, but my memory is not going to allow me to be any more specific.

Murf2u · 06-19-2014, 05:51 AM

I think I've got it now, but just as a clarification, a choke does nothing when it's open. As the name "choke" implies it CLOSES to 'choke' the engine, cutting down the amount of air and thus increasing the fuel to air ratio.

It sounds like one of two things, the choke is just sticky and needs cleaning, or the mechanism that applies it automatically is not working right.

I'd start with a spray can of carb and choke cleaner. Between that and some exercise it might clear itself up.

mel s · 06-19-2014, 07:50 AM

Quote:

Originally Posted by ahicks

First, a choke always closes to start a cold engine. Once started, the choke is supposed to open as the engine warms, allowing the warm engine to breath normally.

Quote:

Originally Posted by Murf2u

a choke does nothing when it's open. As the name "choke" implies it CLOSES to 'choke' the engine, cutting down the amount of air and thus increasing the fuel to air ratio.

Correct

RanCarr · 06-19-2014, 09:39 AM

Quote:

Originally Posted by ahicks

Thinking something is getting lost in translation here, but I think I get what's going on. First, a choke always closes to start a cold engine. Once started, the choke is supposed to open as the engine warms, allowing the warm engine to breath normally.

Yes. I may have had it reversed. Sorry. I probably misunderstood what DH said.

Quote:

This one sounds like it's closing fine, but not opening quickly enough when the engine starts. Probably running really rough and blowing black smoke.

It coughs and hacks and shakes and vibrates - then stalls and shuts off. That's when it's cold and we try to start it from inside the RV.

Quote:

The choke needs to be adjusted. There's a bi-metallic spring inside, that opens and closes the choke as temperatures change. Whoever adjusted it last probably set it to close too tight, so it's not opening quickly enough. It should be set so it's barely closed when the engine is cold.
Depending on age/model, some have a vacuum pull off that helps open the choke when the engine starts. That pull off may not be doing it's job for whatever reason. That could be another adjustment, a broken vacuum line, whatever.

I C&P the info above for DH.

I'm hoping he can get it adjusted himself so we don't have to take it to a shop again. It's an old Onan 4000 from 1993.

Quote:

As far as being more specific, I haven't worked on one in 20 years. It would be easy if it were here in front of me, but my memory is not going to allow me to be any more specific.

I appreciate you taking the time to post this info.

RanCarr · 06-19-2014, 09:43 AM

Quote:

Originally Posted by Murf2u

I think I've got it now, but just as a clarification, a choke does nothing when it's open. As the name "choke" implies it CLOSES to 'choke' the engine, cutting down the amount of air and thus increasing the fuel to air ratio.

It sounds like one of two things, the choke is just sticky and needs cleaning, or the mechanism that applies it automatically is not working right.

I'd start with a spray can of carb and choke cleaner. Between that and some exercise it might clear itself up.

The carb & choke cleaner are worth a try. Once this old gen' starts she runs so good, so smooth. It may be all or part of the problem since the last owner did no maintenance on this poor old Ford Dutchman. He was old and just lived in it and let everything go to pot.