Onan P216

[Vinnie 6]

I just bought a four 16–8 Wheelhorse tractor with a onan P216 and the guy said it did sit for a while. When I started up, it is speed surging high to low RPMs and the choke is opening and closing. I tried spraying gum out in the carburetor that did not work. Any ideas on how to fix this? Thanks so much for your help and glad to be, part of the club   

[Cody 276]

You'll have to remove the air cleaner assembly and take the top of the carb off by removing the 4 Philips head screws. Remove the jets and throughly clean the carb with carb cleaner and compressed air then reassemble 

[lynnmor 7,307]

 

You could try using the straw on the carburetor cleaner and spray into the tiny holes, don't spray a whole lot down the main bore.  Likely the proper fix is to carefully remove the carburetor top paying attention to the linkage and do a good cleaning  I see that someone else beat me to it while I was typing.

 

If you still have problems the carburetor should be removed and cleaned thoroughly.

Edited January 20 by lynnmor

[Vinnie 6]

Great to hear from you.  Thank you so much for your help.  A mechanic warned that I should be very careful taking the carburetor apart.  Are these Onan carburetors challenging to take apart?   

 

Thanks again and have a great day.

[Sailman 1,291]

Try the suggestions above and if that doesn't help you will need to remove and clean the carb. I have found that when cleaning the carb be sure to clear not just the holes in the jets but also the tiny holes in the tubes attached to the jets. I find them stubborn to clear with just carb cleaner and compressed air. I take a fine wire strand from some 12-2 electric wire to clean those tiny holes. Has always allowed me to bring a small engine carb back to life.

[c-series don 8,718]

I wouldn’t hesitate to take it apart, however as with most things I take apart nowadays I take pictures with my phone. Lots of them, step by step. Otherwise I think I’ll remember how it goes and then I start second guessing myself. It’s super easy to reference the pictures during reassembly and then you can delete them later. Like the guys said, carb cleaner and compressed air are key. Good luck and don’t hesitate to ask more questions. People here are more than willing to help you! 

[wallfish 17,010]

Looks like the guys are on it Vinnie

The surging of the rpm typically is caused by an inconsistent air fuel mixture. The carb.

Onans seem to have a common issue with that surging and the first place to start is that carb cleaning as they suggested.

[RED-Z06 2,221]

With the lid of the carb off, there's one particular jet on top, easily accessible, that is most apt to be clogged, makes onans surge.

[Vinnie 6]

Thanks for all your help.  Love the quote nothing runs like a deere when it is chased by a horse.  

[Streetrodchev 800]

If the carb cleaning doesn’t do the trick, the intake manifold is a two piece design that has been known to leak with age and cause the engine to not run properly. It can be separated and resealed. 
 

Also they have a plastic flyball governor spacer that can crack and cause over speeding the engine. 

[Jon Paulsen 290]

3 hours ago, Streetrodchev said:

the intake manifold is a two piece design that has been known to leak with age and cause the engine to not run properly. It can be separated and resealed. 

I would clean the carb even a 2nd time before going after the intake, but these instructions seems pretty good. 

Edited January 22 by Jon Paulsen

[Vinnie 6]

Thanks for your help. I just took the top part of the carb off. I sprayed carbureted cleaner in the Jets and compressed air. I could figure out how to take the jets out of the carburetor but I put it back together and it worked. Thanks for your help. By the way does anybody know how to engage the parking break I’ve tried following the instructions and it doesn’t stay in place. I’m assuming maybe the linkage is broken. 

[Vinnie 6]

Oops, I meant to say I could not figure out how to take the jets out of the carburetor. 

[RED-Z06 2,221]

11 minutes ago, Vinnie said:

Thanks for your help. I just took the top part of the carb off. I sprayed carbureted cleaner in the Jets and compressed air. I could figure out how to take the jets out of the carburetor but I put it back together and it worked. Thanks for your help. By the way does anybody know how to engage the parking break I’ve tried following the instructions and it doesn’t stay in place. I’m assuming maybe the linkage is broken. 

On mine i push down hard on the pedal and lift up on the latch, then release the pedal and the latch holds it.

[lynnmor 7,307]

21 minutes ago, RED-Z06 said:

On mine i push down hard on the pedal and lift up on the latch, then release the pedal and the latch holds it.

And if that doesn't work, perhaps the brake needs adjustment.  If the adjustment is too tight you won't get to the first catch and if it is way too loose again you won't be able to engage the latch.

[lynnmor 7,307]

1 hour ago, Vinnie said:

Oops, I meant to say I could not figure out how to take the jets out of the carburetor. 

Page 7-2 in the Onan Service Manual.

 

One jet is vertical in the drawing and it screws out with a well fitting screwdriver.  The main jet is horizontal behind an exterior plug as shown in the drawing.

 

There is just one challenge in a Nikki carburetor and that is the welch plug shown just above the idle mixture screw, it can be removed so cleaning can be done behind it and then a new aluminum plug pressed in.  I would advise you to leave it alone and spray cleaner and air thru the passages to see if that works, only if you still have a problem come back here for direction in doing the welch plug thing.

Edited January 25 by lynnmor

[Handy Don 12,233]

50 minutes ago, Vinnie said:

Oops, I meant to say I could not figure out how to take the jets out of the carburetor. 

You really want to get/read the Onan service manual.

 

@lynnmor is faster than me!

Edited January 24 by Handy Don

[Vinnie 6]

Don,

Thanks so much.  How do you think the Onan P216 compares to the Kohler 14hp single cylinder?  I know very little about Onan.  Is it one of the better brands for engines?

[RED-Z06 2,221]

16 minutes ago, Vinnie said:

Don,

Thanks so much.  How do you think the Onan P216 compares to the Kohler 14hp single cylinder?  I know very little about Onan.  Is it one of the better brands for engines?

Onan was a popular engine from the 70s, 80s, 90s...they were bought out by Linamar and Linamar was later bought by Cummins.  Parts availability has become somewhat concerning but most stuff can be sourced still.  The K series single was popular from the early 60s through the late 80s, parts availability has also become a concern but again you can still generally find what you need.  I prefer the smoothness of the Onan myself, even with its issues

[Handy Don 12,233]

2 hours ago, Vinnie said:

Don,

Thanks so much.  How do you think the Onan P216 compares to the Kohler 14hp single cylinder?  I know very little about Onan.  Is it one of the better brands for engines?

@RED-Z06 covered it nicely. Both are fine engines and can give excellent service. Very few tasks ask more of our tractors than 14 or 16 hp can deliver.

 

The smoothness and torque of these twins is hard to beat. Also slightly higher fuel consumption.

 

Key factors for ANY air-cooled engine are keeping the oil level correct and making d**n sure to maintain the cooling airflow. On Onans, that means keeping the cooling fins clear of debris and assuring that the gasket that surrounds the oil filter at the blower shroud is always in place (some members have chosen to go further--search for "520 cooling” threads if you are curious).

Edited January 25 by Handy Don

[RED-Z06 2,221]

(P)Performer series onans had a handful of somewhat common, later in life issues.

 

All P series (could) have a plastic governor flyball spacer on the cam, this spacer cracks and slips and you start to see, usually after a couple minutes, excessive engine speed while accelerating the engine, and low engine speed under load.  The fix is to pull the shroud, flywheel, stator, timing cover..and install a metal spacer.  Some P series had a tabbed spacer, some had metal factory...you never know.

 

P220 had intake seat issues..other models never really showed broad problems like the 20hp model...this repair, if possible, involves machining.

 

All P series use a split 2pc intake manifold, it was sealed then riveted at the factory..over time the sealant can fail and the "rivets" can loosen causing a big air leak, surging, bad or no idle.  The fix is to pull the intake, split it, clean it..put on a new sealant and drill the rivets for little nuts/screws.

 

K series had one annoyance...vibration, Kohler attempted to lessen this by putting balance gears inside but the balance gears later became a liability..if they fail they destroy the engine.  Many K and M engines were mounted on rubber isolated shaker plates to make the vibrations tolerable.

 

Points are not a big deal if you understand them.  

 

 

[Vinnie 6]

Thanks.  Glad I do not have the 20hp Onan. 

 

I have a Wheelhorse 416-8 tractor.  I want to pull a 700lb log splitter around my property and I do have some hills.  Do you think this tractor and transmission will be able to pull this weight?  

[RED-Z06 2,221]

29 minutes ago, Vinnie said:

Thanks.  Glad I do not have the 20hp Onan. 

 

I have a Wheelhorse 416-8 tractor.  I want to pull a 700lb log splitter around my property and I do have some hills.  Do you think this tractor and transmission will be able to pull this weight?  

It will pull up to the limit of traction, keep the tongue weight as low as you can until you can tell if it needs front ballast, i had to add 50lbs with my tiller installed to steer.

[Handy Don 12,233]

34 minutes ago, Vinnie said:

Thanks.  Glad I do not have the 20hp Onan. 

Yep. IMHO, the more aggressive valve lift in the 20’s is a factor. The 16 and 18 are less so.

 

 

34 minutes ago, Vinnie said:

pull a 700lb log splitter around my property and I do have some hills

I’ve regularly pulled trailer loads of 500 lbs of damp soil up a steep grade with my 8hp 854 (i did use chains to assure good tire grip on the soft-ish soil and a 25 lb. front weight)! If you make sure to keep the tongue weight in the 50-75 lb range and have good traction you should have no problem at all--in fact, this will hardly tax a 416-8.

Edited January 25 by Handy Don

[wallfish 17,010]

1 hour ago, Vinnie said:

I want to pull a 700lb log splitter around my property and I do have some hills. 

Power isn't the problem but stopping might or could be when going down an incline