Onan Intake Seal Replacement Instructions

[T-Mo-(Moderator) 4,507]

I pulled this off of WFM, and it should apply for all two cylinder Onans.  I redid mine on my '88 John Deere 316 and it sealed up the intake and stop the engine from surging.  If you're having an issue with an Onan surging and you cleaned and cleaned the carb, I suggest you check the intake seal.

 

This may read a bit funny, but I edited out some posts that weren't relevant and only tried to capture the ones that were relevant.  Still, I might have missed some posts that were not relevant and they gotten captured also.

318 Intake.pdf

[squonk 41,171]

While the pics are nice and it's well detailed the guy who did it must have been in the boys room smoking during English class.

[T-Mo-(Moderator) 4,507]

Let's not try and criticized others grammar and spelling, etc.  We all have different levels of education, plus different levels on how we grasp things.  I can point out that your sentence is missing some punctuation, and reads as a run on sentence, but as I said, we have different levels of how well we write, as well as we talk.

 

BTW, the guy who wrote this passed away a few months ago of cancer.  He knew his mechanical stuff to a degree.

[rick 233]

Seeing the French language newspaper in the background of one of the pics, I am guessing English was not his native tongue. It is said that English is one of the hardest languages to learn.

 

[ti-jean 44]

Hi nice revue you did hope it  will help for me my question is how to check if the surging problem is really the intake seal my engine surging up and down went is at warm temperature .

my engine is Onan P216G 1/10538B

Serial 1873267044

 

sorry for my English spelling i am French form North of Montreal in the laurentides

 

thank to help me  

Edited December 7, 2016 by ti-jean
add more

[6bg6ga 272]

If I understand you correctly you are looking for a way to check and see if the intake manifold is really leaking?  I would put some thick grease on my finger and run it along the part line. If the engine smooth's up and the idle speed changes I would say that's the leak. If nothing happens its time to look elsewhere. 

[outback65 0]

Very Nice Package of  important information!  Thank you!

 

Onan's can have multiple minor gremlins which can be frustrating, but most often once they are found, the engines perform flawlessly.  

 

Thank you again!

Outback65

[bc.gold 3,403]

On 4/23/2017 at 3:33 PM, 6bg6ga said:

If I understand you correctly you are looking for a way to check and see if the intake manifold is really leaking?  I would put some thick grease on my finger and run it along the part line. If the engine smooth's up and the idle speed changes I would say that's the leak. If nothing happens its time to look elsewhere. 

The throttle shaft and bushings on my Onan carburetor are badly worn, anyone know where I can purchase a bush and shaft kit.

[KREP 15]

Looks like it’s been taken off line. I couldn’t get it to display. I really need to see this because my 1989 416 has been surging for years. I always blamed the carb. 

[rmaynard 15,531]

On 10/5/2018 at 11:30 PM, bcgold said:

The throttle shaft and bushings on my Onan carburetor are badly worn, anyone know where I can purchase a bush and shaft kit.

I know this thread is old, but I just bought a complete brand new imported carburetor for my P218 for $42.00 delivered. To get a throttle kit and do a rebuild would cost me a lot more just in labor.

[Jerry.Guzzi 6]

On 10/8/2016 at 12:57 PM, T-Mo said:

Let's not try and criticized others grammar and spelling, etc.  We all have different levels of education, plus different levels on how we grasp things.  I can point out that your sentence is missing some punctuation, and reads as a run on sentence, but as I said, we have different levels of how well we write, as well as we talk.

 

BTW, the guy who wrote this passed away a few months ago of cancer.  He knew his mechanical stuff to a degree.

I agree. My wife used to correct my English, I said, if i wanted to marry an English teacher, I would have. I used to spell much better when I graduated with diploma back in 1963, I hated the school I was sent to (military). I know many smart people that don't have common sense, but just ignore.

[cleat 6,091]

On 7/15/2019 at 10:11 AM, rmaynard said:

I know this thread is old, but I just bought a complete brand new imported carburetor for my P218 for $42.00 delivered. To get a throttle kit and do a rebuild would cost me a lot more just in labor.

 

I also know I am replying to an old thread as well but I was wondering how that cheap carb. worked ?

 

I don't know anyone who has used one so I am just curious.

 

Fortunately all of my carbs are working well, I am just wondering.

 

Thanks, Cleat

[rmaynard 15,531]

15 hours ago, cleat said:

 

I also know I am replying to an old thread as well but I was wondering how that cheap carb. worked ?

 

I don't know anyone who has used one so I am just curious.

 

Fortunately all of my carbs are working well, I am just wondering.

 

Thanks, Cleat

 

The carburetor is still sitting on the shelf. The old one started working correctly and I have not swapped them out yet. 

[KREP 15]

Krep here again.  I did some experimenting on my 416 which I said was surging, just a few posts up. Mine stopped surging as soon as I put some non-ethanol 89 octane fuel in it. It sat all last winter and my snow thrower sat since last Feb.   I drained the fuel in both, gassed them up and no issue. My 416 ran great all summer. I just started the snow thrower on the first of December and no surge. I was ready to switch carbs too. Please try replacing fuel first. 

[redone 45]

Hi All.

I am reaching out  to everyone on Red Square. I am looking for Onan internal parts as to rebuild my engine. It is a B41 series. It dose run ok, but with 700 hours on this motor, it was not maintained well. I need to get this rebuilt before a valve drops. That could damage a lot. My tractor is very nice 520HC 

Well thank you

Bill 

[davem1111 2,030]

On 12/5/2020 at 1:32 PM, KREP said:

Krep here again.  I did some experimenting on my 416 which I said was surging, just a few posts up. Mine stopped surging as soon as I put some non-ethanol 89 octane fuel in it. It sat all last winter and my snow thrower sat since last Feb.   I drained the fuel in both, gassed them up and no issue. My 416 ran great all summer. I just started the snow thrower on the first of December and no surge. I was ready to switch carbs too. Please try replacing fuel first. 

 

This is interesting. I just bought a 520-8 with about 620 hours on it. It had been sitting outside for quite a while and was not in really bad shape but not maintained "well".  The tank was empty when I went to see it so the PO dumped some gas of unknown age, etc. into it. It runs, but it surges a lot, several revolutions firing then seems to die, then cycles again. I assumed it just needed a good carb cleaning and adjustment, but now I'm wondering about the intake and also anything else like the fuel. I have some 90 octane non-ethanol so I'm going to drain the whole thing and try that. I did put a new fuel filter on it, since I couldn't even see into the one that was on it. I also took the top of the carb off, took the float out and cleaned the bowl then sprayed carb cleaner everywhere I could reach. That didn't seem to help. Haven't tried any adjustments yet, but so far I'm under the impression that these don't have both a main mixture screw and an idle mixture screw like the Kohler singles have.

 

I thought I'd see how much a replacement manifold is, and it looks like it would cost me at least $50-100 with shipping for a used one, which might not be any better. So if there are any signs of manifold leakage I may try the procedure in this PDF to re-seal it.  Also going to replace the spark plugs, wires, and coil wires.  One question:  does the coil need to be grounded by its bolt(s) to the engine?  I noticed that the coil was not bolted down, it's just "free floating".  I intended to get that bolted down but didn't do it yet.

 

If there's anything else that could make this engine surge or run erratically, I'd be interested in hearing about it.  Thanks!

Edited June 7, 2023 by davem1111