Correct way to start Onan 4K generator

[CodyClassB]

What is the correct way to start Onan 4K generator? My generator won't start unless I press and hold the start button for about 30 seconds to 45 seconds. Is that considered over-cranking? I can also press, hold and release the start button after 10 seconds. Then press and hold for another 10 seconds before the generator gets started.

thanks

[4x4van]

Mine (1988) doesn't have the prime feature, but I added a toggle switch inside the generator compartment to energize the fuel pump. I turn it on and listen; it usually takes about 10 seconds (first start of the weekend) and I can hear the pump change sound as the lines become pressurized. At that point, I turn the toggle off, hit the starter button, and it starts within 3-5 seconds. The rest of the weekend/trip, no need to prime.

[johnwalkerpa1]

wa8yxm wrote:
Instruction manual says PRESS STOP till the light comes on (Assumes there is a light) I suggest you hold it a bit longer (15-30 seconds) )

that is usually the key...especially if the generator is a ways from your gas tank...they lose fuel pressure when they are off for a while and it takes a while to get it back...my gas tank is 20 feet away from the generator...about 30 seconds usually does it for the prime...the light comes on at about 8 seconds....not long enough..

[HeWhoIs]

My Onan 4k MicroQuiet Generator starts right up from the remote switch now. Usually takes about 5 seconds. We use the RV at least twice a week, so the generator is used frequently, if that makes a difference.

Might want to check the house batteries. Are they old? My generator took quite a long time to start for the first couple weeks after we bought the RV (used), then it just stopped cranking all together. Turns out the house batteries were going bad. New house batteries now, and no issues.

[coolbreeze01]

Rotzilla wrote:
I have a 13 model 4k, I usually use the remote start switch inside my camper, crank for 15 sec, pause and crank 15 sec more. If its cold it usually starts on the 3rd attempt.
I do not go out and use the prime function on the gen set, if I did it might start faster, who knows.
Yours sounds similar to mine.

Pushing the STOP is the prime function on my remote.

[Rotzilla]

I have a 13 model 4k, I usually use the remote start switch inside my camper, crank for 15 sec, pause and crank 15 sec more. If its cold it usually starts on the 3rd attempt.
I do not go out and use the prime function on the gen set, if I did it might start faster, who knows.
Yours sounds similar to mine.

[Snowman9000]

DownTheAvenue wrote:
Google is your friend.

Unfortunately, nothing in that manual addresses the OP's problem.

[wa8yxm]

Instruction manual says PRESS STOP till the light comes on (Assumes there is a light) I suggest you hold it a bit longer (15-30 seconds) Then press START. It should start within 30 seconds.. Mine (is bigger than yours) usually does not.

ANother method that I have found effective is this.

Press start.. Just a second or less .. Now wait, like 30-60 seconds. Press again, Mine USUALLY starts within 15 seconds on the 2nd press.

You can combine (Start by pressing STOP. then press START for 1-30 seconds. then wait 30 seconds and press again)

[DownTheAvenue]

Google is your friend.

[tpi]

Prime about 20 seconds. Then as many 10 second cranks as necessary to start with a 20 second pause in between. Mine usually starts the 3rd crank.

This is 1975 technology. In the old days some cars were cranky starting cold as well 🙂

[coolbreeze01]

Does the altitude setting affect starting?

[darsben]

Try a fuel filter with a check valve

[Snowman9000]

My current one and my previous one were the same way. It take an ungodly long time to prime them. And it seems no matter how long I prime, it still won't fire up without a few tries at cranking.

I have suspected the choke is set too lean but have not gotten around to looking at it. I downloaded the service manual and will eventually check the choke adjustment.

If not the choke, then it's a poor design in some way. Maybe emissions tuning has created this problem. Again though, the choke should take care of that.

[RJCorazza]

My previous Onan 4k Emerald 2 (1996) did not have a prime function. Check your manual. As far as cranking, 30+ seconds is too long for routine starting. If it starts using your second pattern (10 / 10) go with that, or better yet, try breaking it up in 5 second cranks like Bobbo above does.

[Bobbo]

I prime mine for 60 seconds, timed with my watch, by holding the STOP button before I ever try to crank it. I can hear the fuel pump so I know it is priming. Then, I crank for 5 seconds on, 5 seconds off. It takes 4 or 5 repetitions of this before it starts. More in colder weather.