Priming required on 4KW Onan Microlite

[midasman]

I have a 2019 Entegra Esteem 30X (same as Jayco 30X duh)...It is necessary to prime the Onan EVERY time for at least 30 seconds for it to start. Fuel tank is FULL. Is this normal? Is there a choke that might be set too lean? Once it starts it seems fine. Sometimes it will start and run for 5 seconds and stop. More priming makes it go. Thoughts? Even if it has been 95 degrees all day, it STILL needs it's prime job. When priming, the red light is on and I can hear it "ticking". Thoughts?
Thanks in advance.

[A32Deuce]

I have that man. gen and just hold the prime button down till the light is on the hit start. Can't be bothered to time it. Depends on outside temp how long its held down.

[JONWisconsin]

Pete, that is the way mine works. NP

[twinboat]

The prime switch runs the electric fuel pump, nothing else.

It should only be needed after the generator has been sitting for a few days or longer.

A carburator bowl is like a toilet tank. It fills until the float shuts off the gas coming in with a valve.

While sitting, some gas can evaporate from the carburator bowl. Instead if cranking the engine to send power to the fuel pump, slowly filling the bowl, you bypass that with the prime switch. Once the carburator bowl is full, the fuel pump just pumps against the needle valve, like while running.

If its not starting quickly, after sitting only a few hours to a day or so, you may need the choke adjusted. That closes off the intake air, causing the engine to pull a bit more gas in. Once running, engine vacuum and a choke heater opens it.

If your handy, remove the air filter, and see if the choke valve is closed during startup.

Here is a great image of how carburators work.

[twinboat]

One other point;

When you shut down the generator, touch and release the stop switch.
If you hold it until the engine stops, you may be drawing gas from the carburator. There is a valve on the bottom that blocks the main jet. Holding the stop switch may keep that open.

[BirchyBoy]

Mine doesn’t have a prime button on the switch inside the coach. It’s just start/stop. Does yours have one inside?

Have you checked the altitude adjustment knob? If you’re above see level it may need to be changed.

[Isaac-1]

Depending on the model year, pressing the switch to the stop position when the generator is off will provide priming.

[twinboat]

A quick test is to have someone hold the stop switch while you listen for the fuel pump to click, click, click.

It may have a 10 second delay before it starts clicking.

[A32Deuce]

Start/stop is the prime pushing down on stop. That's how several I have seen are.

Originally Posted by BirchyBoy

Mine doesn’t have a prime button on the switch inside the coach. It’s just start/stop. Does yours have one inside?

Have you checked the altitude adjustment knob? If you’re above see level it may need to be changed.

[ThePowells]

Since it is a 2019 I would believe that the Owner's Manual hasn't been lost yet. Investing 20 minutes of reading and hands on looking will be of a great benefit.

[midasman]

DVD wouldn’t play on Mac. On line manual not too helpful. Seems to be a choke problem. For some reason a 1 minute prime seems to give a quick start.
Thanks!

[Mudfrog]

Originally Posted by midasman

DVD wouldn’t play on Mac. On line manual not too helpful. Seems to be a choke problem. For some reason a 1 minute prime seems to give a quick start.
Thanks!

The fuel pump only has to supply a small amount of fuel to the carburetor. It should not take a minute to prime. Something is out of whack and needs to be adjusted.

[aether_one]

Manual says 20 to 45 seconds before starting. Unless I've already run the generator that day I always prime for at least 20 seconds. The generator starts much quicker and does not crank on the starter for very long.

You can't hurt it by "over-priming"; you can hurt it by cranking the starter for long periods.

[midasman]

It does seem to need a bit more choke but I couldn't see any way to adjust it. The altitude adjustment IS SET for sea level and I'm at around 25 feet...I only have 10 hours on the Onan. Hopefully a few more hours will help???