Engine Blow By ...

higgy · Jan 29, 2004

the old gray marine and gm 2 cycles would do this once and awhile.

I have seen this happen with industrial air compressors as well, when a seal or ring is broken oil or vapor from the crank case gets into the compression chamber and it will diesel for a short while, until it comes apart.

It is truly a scary sight to behold.

TOMLESCOEQUIP · Jan 29, 2004

When I built my house in '93, I bought an old mustang skid-steer loader to assist me with back filling and landscaping. It had a wisconson V4 and smoked like a freight train (MORE than a freight train actually) out the breather. After running it about an hour it would slobber it's way through a quart of oil out the breather ( talk about real blow-by !!) My friends who saw it would laugh and remark about the excessive use of oil...............But in that hour I moved 13 tons of bank run for the approach to my barn............All for the cost of a $1 quart of wally world oil !! I told the friendly nay-sayers that I would gladly shut off the smoking mustang if they would spread and level the next load of 13 tons for the $1 I just spent on oil !! I eventually routed the breather hose into a old tasters choice instant coffee jar ( large hole in center for hose, small holes punched around outside of lid for vent action).........And then I could reuse about 2/3 quart of the spewed oil after an hour.(YES it was still on there when I sold it, NO I don't feel guilty !) I used that old skid loader for the entire summer and sold it at a slight profit when I was done using it . I don't think the old wisconsin had enough power left to break any major internal parts as long as the oil was checked periodically.This is probably the only good ending story about blow by you'll hear............Tom

jinman · Jan 30, 2004

( It had a wisconson V4 and smoked like a freight train (MORE than a freight train actually) out the breather. )

That sounds like my old Ford 4000 Industrial that smoked everywhere there was an opening: exhaust, intake, engine crankcase, and sometimes even transmission. /forums/images/graemlins/blush.gif It would start and run just fine after I put a 12 volt system on it and added anti-foul adapters to the spark plugs.

It had a very powerful FEL and I used that tractor to clean up a mobile home park after I closed it. One day a cop was cruising by and stopped while I was working. He jumped out of his car and came running my way, so I shut down the tractor and said, "What's wrong?" All of a sudden he stopped in his tracks and said, "Oh! Never mind. I just thought your tractor was on fire for a second and you didn't know it." /forums/images/graemlins/shocked.gif As soon as I shut down the engine the smoke had stopped. We both got a good laugh out of that. /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

The tractor was still that way when I sold it, but the new owner said he had a shop and would rebuild the engine immediately. /forums/images/graemlins/cool.gif

jinman · Jan 31, 2004

( No rush to provide the info, )

The attachment is a picture of the crankcase breather on an Onan gasoline engine. After looking at it, I think my reed valve just may be stuck. Anyhow, the specs say the compression for the 16 and 18 HP engines should be between 75 and 115 psi. If yours is smoking, it's probably either the rings or the crankcase breather letting too much crud into the carburetor. I have other specs from my Service Manual, so if you have any questions, maybe we should start a thread specifically about the Onan. Some other folks might want this info too. /forums/images/graemlins/smile.gif

Junkman · Jan 31, 2004

Here is a link to a Yahoo Onan Engine club that has a lot of knowledgeable members that might be able to help you with the specific information... It is like going to a tractor specific club here... specific knowledge vs. general knowledge.. web page

JDgreen227 · Jan 31, 2004

jinman,

Thank you for the info, if I had known better I would have purchased the shop manuals for my 318 back in '89, they were much cheaper then. These days, I am the guy who carries no cash.... /forums/images/graemlins/grin.gif

JDgreen227 · Jan 31, 2004

Junkman,

Thanks to you also. I belong to the Yahoo JD Garden Tractor group but was unaware of the Onan Engine Club.

Sigh....so many interesting websites, so little time to surf them. /forums/images/graemlins/frown.gif

Bill

Junkman · Jan 31, 2004

There are engine specific clubs for each brand. These clubs are moderated so you won't be getting any **** messages with your answers..
Tecumseh
Kohler
Briggs & Stratton
Onan