Onan Rummmmmmmmmm Rummmmmmmmm Rummmmmmmm

[Tankman 3,516]

Well ran the Onan P220 today. Was runnin' fine, haven't run the 520-8 since late fall.

 

The Onan ran fine, love the sound. Then, without warning started to make noise, no banging. Like it was hunting; rummmmmmmmm rummmmmmmmmmm    rummmmmmmmmm rummmmmmmmmm.  The sound goes on till I hit the ignition, off.

 

Any ideas, while I am a steel worker, keep the herd of Stallions very presentable, not to much with engines. 'Specially this 20 hp Onan.

 

I'm thinkin', "Fuel problem."

 

Any other ideas? The rummmmmmmmm rummmmmmmmmmm rummmmmmmmmmm rummmmmmmmmm most surely eventually, cause problems.

 

Finished mowin' d lawns but, till I figure this one out, goin' to use a 400 series Horse.

[Martin 2,131]

Fuel problem, clean the carb. Many threads and discussion on the subject...

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[varosd 1,185]

Fuel problem, clean the carb. Many threads and discussion on the subject...

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I agree with Martin about dirty carb.

since you started it last Fall, it could have stale gas all gummed up. obviously, fresh gas, carb cleaner etc. 

does it sit outside?  check for insects etc plugging up things. 

How long did it run before the sound started?

Is the gas tank clean or possible pine straw, leaves in it from the leaf season?

[Tankman 3,516]

OK, carb cleanin' this week. I always groom (clean) the Stallions; oil, tires, grease, plugs, whatever the Horse needs to stay healthy.

 

Always indoors, only outdoors to work, then into the barn they go.

 

Carb cleanup is just what I though. Thanks Horseys for the input!  I'll update after the carb rework and cleaning.

[Wishin4a416 2,190]

I know it could be a lot of things but, my 18 did exactly that and it ended up being a 50 cent welch plug that blew off the carb while plowing one winter. Just something else to check out.

[Martin 2,131]

good point Jack. I had one that did that, not good if the plug is missing as they are a bear to find without buying the expensive carb kit. do you have a source for them? ( i noticed you said they are a 50 cent part)

Edited May 11, 2014 by Martin

[Wishin4a416 2,190]

good point Jack. I had one that did that, not good if the plug is missing as they are a bear to find without buying the expensive carb kit. do you have a source for them? ( i noticed you said they are a 50 cent part)

My local JD dealer  got it Martin. He is able to order individual parts instead of the whole kit.

[Wheel-N-It 2,968]

Tankman, don't forget to give that Horse some Seafoam. After your carb cleaning run five gal of gas mixed with 8oz of Seafoam. It always works for me.

[Tankman 3,516]

Well, used carb cleaner and, a believer, used SeaFoam spray.

 

I can stop the rummmmmmm rummmmmmmmm rummmmmmm which turns out to be the governor "bouncing." If I hold the governor (stop it from movin') the rummmm rummmmmmmmm rummmmmmm stops.

 

Input, me not bein' a motor head, is needed to get the Stallion feelin' and soundin' well. Advice, help, needed, prayin' for guidance. 

[Tankman 3,516]

Using Gumout spray carb cleaner, could get the engine to run but, with a little "hunting."

 

Every few hours I run, each time runs smoother, and spray clean again. Don't know if it makes any difference, input appreciated, but found if I remove the fuel inline filter, I can spray cleaner in the short line that goes to the carb. Seems to be doin' something. 

 

Short of getting a smoother runnin' Onan, guess I can remove the top of the carb to clean out the bowl or, is this not feasible?

 

Last bowl full of cleaner, soaked an hour or two, ran the engine and thought, "This'll mow fine." Engine ran but, had to open the throttle a bit when standing. Heading in the right direction or not? Thanks Stallions!

 

**PS** Tried more Gumout carb cleaner, down the fuel tube. Waited a couple of hours and WOW runnin' smooth 'n clean. Just mowed an acre, clean. Not a single problem. Think I'll clean the carb more often. Duh!  

Edited May 12, 2014 by Tankman

[MalMac 1,331]

Well as said several times before, ethanol causes more problems with these small engines. I have cleaned the carb on my 520 lots of times and did the SeaFoam thing. What I have found to work the best is using 94+ octane. I don't know the % of ethanol in it because they don't put it on the pump anymore around here. All I know it really has helped the residue gummy factor on the Onan. It's been two years now since last cleaning and still running just fine. I will say that I do not let it sit for long period of times with gas in it 2 months or longer.

[Kelly 1,029]

you need to remove the top off the carb and clean the bowel out and spray the tiny holes out, spraying clean at a complete carb will do little. 

[boovuc 1,090]

As Kelly stated, just putting some carb cleaner down it's throat won't make much of a difference if any difference at all. Just remove the air cleaner assembly and take the top of the carb off. There is a post here on RS with each detail of how to do it and what to spray.

I have to show up at work in a few minutes and a quick search didn't yield what I was looking for. Hopefully others will search and post it for you.

 

Thanks!

[Tankman 3,516]

BooVuc:

 

The Onan is runnin' like a top today! Smooth! I was sprayin' the Gumout carb cleaner into the fuel like that leads to the

carb. After waitin' an hour or so, several times, running like new today.

 

Didn't take any of the carb apart although I did remove the air cleaner housing and spray clean the outer parts of the carb.

 

I am amazed that I didn't remove the carb and rebuild and/or replace it. 

[MalMac 1,331]

Tankman, Glad you did not need to take the carb apart but.......... Like Kelly suggested about cleaning out the bowl is recommended. I cleaned mine and it ran great then would act up again. Repeated this two or three times. What I found out was there was so much gunk built up in the bowl that every time I used a crab cleaner it would loosen it up and cause problems. Finale tore carb top off and cleaned that bowl out and wiped floats off and poke and prodded all the little holes. After I got it all cleaned up never had a problem again. So If your tractor starts it again I would suggest getting that bowl cleaned out. It will amaze you the amount of junk that will get in there and build up over time, even with a fliter on.

[Tankman 3,516]

Thanks MalMac. Goin' to clean the bowl tomorrow.

 

Once a Jarhead always a Jarhead! I'm awake and followin' orders!