520 H 1100 hours SMOKES BAD

[budman2 57]

I just bought a 1995 520H Wheel Horse tractor that has about 1100 hours on it, smokes like a freight train! I checked the compression with full throttle and choke wide open, 120psi on both cylinders! Any and all help would be greatly appreciated, Thanks budman2

[pfrederi 18,703]

Diesel Freight trains blow black smoke...Steam freights blow gray/white smoke and sometimes black.  What color smoke do you have...makes a difference.

[budman2 57]

It looks like a dark gray and smells like oil burning, I have changed the oil twice since I have had it as the prior owner let it get very black! I thought maybe the oil rings where maybe stuck as the tractor has been setting a long time! runs super strong, I don't know what else to check! Thanks for your response, budman2

[Elkskin's mower junkyard 1,117]

what weight oil u put in it and type never run synthetic in a high hour engine thats use to regular oil

and alsio if you can make a video

 

[budman2 57]

I use straight 30W Valveline!

[Elkskin's mower junkyard 1,117]

Just now, budman2 said:

I use straight 30W Valveline!

well dark smoke sounds to me like running too rich. i have never seen a oil burner do black smoke heavy unless it was way to rich from gas. usually if its alot of oil being burnt it will appear a white color out muffler then out a couple feet it will have blue tent but i mean alot like scored cylinder bad lol. reason i suggested a video

[budman2 57]

OK, thanks! I will post a picture of it tomorrow maybe that will help! budman2

[pfrederi 18,703]

Blue/white oil  Black usually fuel.

[budman2 57]

Thanks much! I will try and find out tomorrow if it is a rich fuel mixture, I sure hope thats all it is, budman2

[cleat 7,263]

Take off the air filter covers and check that the choke is coming all the way off.

 

The Onan's will run with the choke on due to a spring on the choke butterfly but it will smoke.

 

 

[budman2 57]

OK, I will do that in a little while! thanks for the input, I have racked my pea brain trying to figure this one out! budman2

[rmaynard 16,342]

@craftsmanmowerfreak I'm curious to know your reasoning for not running synthetic in a high hours engine. I have nearly 1600 hours on my Onan 16 HP and at 1500 hours switched from dino oil to fully synthetic with no issues. No oil burning, no leaking.

 

@budman2 I'd put my money on stuck or worn rings. You can get good compression and still have a bad oil ring.

[budman2 57]

OK guys I have tried leaning the carb, made sure the choke is opened, changed to mobel1 full synthetic 10W-30 oil and it is still smoking bad! I suppose the next step is to part it out or sell it as is! I will try and load a couple of pictures of it smoking! picture number three is before I started it!

[pfrederi 18,703]

That looks like  oil smoke to me.  Older tired Kohlers will do that far a minute or so when they first start up but then it seem to clear up.

[budman2 57]

Yah I think it is oil burning! Time to part it out, or sell as is, Thanks for all the input guys I do appreciate it, budman2

[squonk 43,899]

Try adding a little Sea Foam to the oil, running it a while and then draining it. You say the old oil was very black.I've had luck with Sea Foam freeing rings and lifters. You could also have clogged oil returns overwhelming the valve guides and seals with too much oil.

[budman2 57]

Squonk   I tried putting 1/2 can of seafoam in with the oil, let it run about an hour, with no luck! somebody else sugjested changing the oil to synthetic to see if that would clean it up, tried that also, it is still in the motor now, still smoking bad!  don't know how long this has been setting in a garage but the oil that came out of it had some lumps in it (no metal though) and very black! thanks for your input, I hate to part it out as it runs good its just a smoken machine, budman2

[cleat 7,263]

Well, you can pull the intake and exhaust then the valve covers to set the valves and verify as Squonk said that the oil drains are open under the tappets.

 

You can also pull the heads for decarboning and check the cylinders for scratches or other damage.

 

Also, you can perform a leak-down test to verify the rings are sealing properly (you may need to find a mechanic that has a tester).

 

This gets a little costly due to the Onan gaskets being expensive but should likely be done anyways if it has not been done in a long time.

 

[onanparts.com 185]

8 hours ago, budman2 said:

Squonk   I tried putting 1/2 can of seafoam in with the oil, let it run about an hour, with no luck! somebody else sugjested changing the oil to synthetic to see if that would clean it up, tried that also, it is still in the motor now, still smoking bad!  don't know how long this has been setting in a garage but the oil that came out of it had some lumps in it (no metal though) and very black! thanks for your input, I hate to part it out as it runs good its just a smoken machine, budman2

 

Stuck oil control rings most likely. But it's also possible the crankcase breather is stuck open/clogged up. Easy check is looking at the air filter and it's housing to see if oil is present. If dry run engine with air cleaner/filter cover off and see if any blowby is coming out the breather tube. 

 

Blowby means stuck oil rings. Under $100 for a set of STD rings, head gaskets and oil pan gasket. No reason to part out a nice tractor due to a stuck oil ring. Might get lucky and it's just the breather that's gunked up.

[BESTDOGEVER 218]

Are you getting oil in the air cleaner /intake? My relief valve was stuck and I was getting oil pouring in from the breather made it smoke about like that .

[budman2 57]

Yes there is some oil in the breather pan, got tired of messing with it and sold it to one of the members here on red square! I just don't know that much about the onans, but I do hope it is an easy fix for the new owner, Thanks for your input though budman2.

[Elkskin's mower junkyard 1,117]

if it was me i would of just repowered it. onans are $$$ to fix. i had one in a sears fuel pump went out and i wasnt paying 120 plus for carb kit so i sold it

[Uncle Buck 246]

Really a poor reason to part that machine out if you ask me. Replace the rings and do the valves and seats. That is just too nice of a machine to part out.