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Chieftain27 · 08-15-2020, 01:03 PM

My Onan Emerald Plus 4000 generator is not running.
I just replace fuel pump and Filter thinking the pump was bad.
I actually tested the new one After installing and fuel is steadily being pumped to carburetor on generator.
When I push the button all it does is crank but it never actually turns over.
My reason for assuming it was the fuel pump in the first place is at times it would run sometimes good, sometimes really weak and sometimes not at all. It would turn on and then shut off.
As of now I have fuel pumping but no start so far.
Any ideas?

ByeTheWay · 08-15-2020, 02:30 PM

I had one with similar issues. There was an electrical wire coming from the automatic choke that I disconnected. Problem solved.

Chieftain27 · 08-15-2020, 02:50 PM

Quote:

Originally Posted by ByeTheWay

I had one with similar issues. There was an electrical wire coming from the automatic choke that I disconnected. Problem solved.

Can you elaborate a bit more? Do I have to take the carb off the gen?

lllkrob · 08-15-2020, 04:05 PM

When you get the carb off the generator take it to your friendly Onan dealer and buy a new carb. It's your problem.

ByeTheWay · 08-16-2020, 11:59 AM

Quote:

Originally Posted by Chieftain27

Can you elaborate a bit more? Do I have to take the carb off the gen?

I found the fix by accident. In poking around for a fix I cleaned the connection and forgot to re-attach it.

I did not remove anything except the wire going to the electric choke which is near the carb. The wire had a female Insulated quick connector. As I recall the male end was sticking out from the choke housing.

I have since traded rigs or I'd send a picture.

I just remember I had a new carb put on in a shop, but it did not fix my problem.

Isaac-1 · 08-16-2020, 01:20 PM

Did you use a genuine Onan low pressure fuel pump?

Chieftain27 · 08-17-2020, 07:27 AM

Quote:

Originally Posted by Isaac-1

Did you use a genuine Onan low pressure fuel pump?

Yes, I’ve done a few more tests and still nothing. I tried starter fluid and it turns on for a split second but then that’s it. I also unplugged the low oil sensor and nada.

US1 · 08-17-2020, 07:56 AM

Bought my rv in Jan with the Onan 4000 and I had the same problem, it would just crank. starting fluid would allow it to start for a few seconds before the fluid was used up. This told me it was a simple fuel (carb) issue. Fuel pressure was good. If the gen has sat for a good amount of time, the fuel will evaporate and leave a nasty scale inside the float bowl and passages. All I had to do was pull the carb and drop the float bowl to clean. Spray all passages, needle and seat with Carb cleaner. 30 min job and $4 for cleaner. Take care when pulling apart so gaskets don’t tear.
I then installed a fuel shut off valve right before the carb inlet. When I’m done using the rv, simply close the valve and let the gen run till it empties out the carb. Usually less than a min.

Chieftain27 · 08-17-2020, 10:31 PM

Quote:

Originally Posted by US1

Bought my rv in Jan with the Onan 4000 and I had the same problem, it would just crank. starting fluid would allow it to start for a few seconds before the fluid was used up. This told me it was a simple fuel (carb) issue. Fuel pressure was good. If the gen has sat for a good amount of time, the fuel will evaporate and leave a nasty scale inside the float bowl and passages. All I had to do was pull the carb and drop the float bowl to clean. Spray all passages, needle and seat with Carb cleaner. 30 min job and $4 for cleaner. Take care when pulling apart so gaskets don’t tear.
I then installed a fuel shut off valve right before the carb inlet. When I’m done using the rv, simply close the valve and let the gen run till it empties out the carb. Usually less than a min.

I thought I’d have to do exactly what you said and I like your makeshift idea. Did you have to drop the gen to remove the carb?

US1 · 08-18-2020, 05:08 AM

Nope. All done right from the access door. Just took a little creative work to get to the rear carb bolt though. Once done, I did unhook the pump inlet hose and run it to a gas can with a mix of Seafoam and let it run an hr for extra cleaning measures.

Chieftain27 · 08-18-2020, 10:23 PM

Quote:

Originally Posted by US1

Nope. All done right from the access door. Just took a little creative work to get to the rear carb bolt though. Once done, I did unhook the pump inlet hose and run it to a gas can with a mix of Seafoam and let it run an hr for extra cleaning measures.

Nice tip. Any recommendations on instructional videos possibly. I figure a lot out on my own but it’d be nice to see it done first. Any challenges? or is it pretty simple?