Generator cranking a long time

I have a Onan 4000 in my 1990 Winnebago. It does not have a prime button. The in-cabin start switch is two-way only. It is either rocked to "stop" or "start/run".

Typically I have to press "start/run" for about 5 seconds and then I give it a rest, then I press it again and it fires up. Presumably it is priming on the first try.

I suspect that when you shut down the generator while it is hot the gas evaporates out of the carb bowl so that the next time you go to start it it is empty. Probably why they went to dedicated priming options later.

If we haven't used our Onan for awhile it will require priming to get it started. The switch we have has a dual purpose, when pressed one side starts the genny, the other side primes the genny. Might take a couple of primes to get going. We use Stabil and Seafoam to keep fuel and delivery system in good working order.

Mine does this also and I just redid the whole thing including new carb, filter and pump. From inside even after priming... it just cranks.... but go outside to the generator and push the start button and it fires right off...

path1 wrote:


If yours is like mine.....

Look real close at switch. See bottom at lower left where it says "stop/prime"

If genny is not running, push in "stop/prime" switch and you should here a little pump, when it makes a different noise, let go. Then push top of switch and starter should engage and start the genny.

Thanks all. My button is a small toggle switch and there is no "prime" printed on it. I held it in on stop and the light didn't come on. I will get the manual out and will try priming method also.

I'll prime for 20 seconds, then give about 10 second attempt to start. Usually fails, reprime then try again. Usually starts. If not it will always start on 3rd repetition.

loneryder wrote:

aeejbe wrote:
Just to rule out the obvious... ... Do you PRIME the generator beforehand?

Have never seen any prime button. I'm pressing the start button on my control console inside. I've had the cover off to change the oil and didn't see anything but another start button. It has 10 hrs on it. A 2015 rv.

There is NO dedicated prime button. The process of priming an Onan gasoline generator is to push the opposing side of the start button like a teeter totter. You must hold it for a while before the pump actually starts priming. The light on the switch or control panel will finally turn on which indicates the pump is pumping fuel to the carburetor. I recommend pumping/priming for 5 seconds.

The start button on the generator itself, and the start button on the control panel inside the house work the same way.

If all is very quiet, we can hear when the pump is running for priming. After 5 seconds of that, I attempt to start the generator. If it won't start, I repeat the process.

It would take me at least 45 seconds like you loneryder, of constant cranking if I did not first prime the pump to get fuel right up to the carburetor before starting.

Don't forget that a gasoline generator gets it's fuel from the main fuel tank and it "officially" stops running when the main tank hits 1/4 full when parked level. Our rig seems to be set a bit higher meaning it's closer to 1/3 full before the generator starves of fuel. So if the generator never starts, your main fuel tank might have too little gas inside to support generator operations. This is designed so that you never accidentally empty the main tank, rendering yourself stranded.

short starts..wait till fuel pump goes off and do it again...I baby the starter...Propane..you can buy a regulator with the button in the center ..when pressed it feeds propane into carb...not a problem (usually) on Onan..but if you have a Generac..it is a great help...I had to buy my propane regular..on line..and was a pain with the pipe fittings .to get loose...but once installed it made it start right up.....

this is for propane only...big help for Generac..which I know longer have..THANKGOODNESS!!!

http://www.propane-generators.com/garretson.php

The prim button on my 07 is a stealth primmer. It is not marked and you would not know about it unless you read the owners manual or was shown. It is there though. I press stop until I get a light and then start. Fires up quickly.

I follow j-d's procedure as well, although sometimes I have to prime 3 times. Our Remote switch doesn't say Stop/Prime, but I hold it in the stop position for about 5 seconds. I can hear the pump run. If it doesn't start after the 3rd try, I usually run the engine to add a little umpf to the house battery. I have noticed that the generator starts best when the battery has a full charge.

I may hold the start button for as long as 10 seconds, but definitely not 45 seconds. If I am not mistaken, the starter is at the back of the generator. It is a hassle to change, so be nice to the starter.

-Michael

Our ONAN 4KY often takes two "priming cycles". I prime, crank, and if it doesn't start in 5 seconds (or so, I don't time it but 45 is a LONG time to listen to a starter), then I prime again. When I crank after the second priming it starts darn near immediately.
You're right trying to conserve the starter. Changing it is NOT an easy task.