She's a Smoker!

[palongee1]

Ive been going over some things on my g11 (has a g9 engine) the last few days, adjusted valves, fixed the vacuum control valve issue etc, well now the thing smokes like a chimney after it has sat for awhile, it seems to burn it off after a few minutes but smokes bad initially, the compression after adjusting the valves was reading 150 (100 before setting them where they should be), anyhow, I just pulled the head thinking its probably a valve seal/guide issue possibly. The cylinder looks great, top of the piston is clean, there is a bit of carbon built up on the valves. I haven't done much internal engine work and this may be a really stupid question... I rotated the engine till the piston was at the bottom of its stroke then wiped the cylinder walls clean, if I crank the motor for a couple seconds is it normal for oil to make it all the way up the cylinder? I don't know if the scraper rings are gonna do what there supposed to do without the combustion actually taking place, it is quite a bit of oil making its way to the top of the cylinder after just a few seconds...Thanks in advance...

[smallblock450sl]

Sounds like the oil rings are gone.

[palongee1]

Unfortunately I'm thinking the same thing, with the head sitting on the bench I dumped some fuel into the intake port and had some leakage past the valve, not much but some. Book says there shouldn't be any, the surface that the valve seals to the head looks nice and shiny clean but obviously its not as tight as it should be. Looking at the top of the piston I only see an arrow, if it were an oversized piston would it be marked on the top or would I need to pull it apart to see what I've got? I don't know if id need piston/rings or just new ring set if in fact it is the oil ring? Or maybe say screw it and do a whole swap :) At the cart place today the guy was trying to see me a new carryall, only 9900.00...LOL

[palongee1]

Another question, does the valve seal just pop off, looked around for how to actually remove it, nothing I could find online or in the book talks about the process, thanks again!

[smokindawg]

The valve seals fit down over the valve stem and just slide over it. Nothing holds them. I was going to say, if it smokes bad when you first start it and then goes away it could be a valve seal problem. Not sure about if they free float or fit tight over the valve guide though.

Wasn't sure if these engines even had valve seals.

[cgtech]

Originally Posted by palongee1

Another question, does the valve seal just pop off, looked around for how to actually remove it, nothing I could find online or in the book talks about the process, thanks again!

When they are new supple rubber, they pop on & off without too much hassle. When they are baked into a plastic-like substance, prying them off is tough.

[smokindawg]

Usually they get hard and break apart and that's what causes them to start smoking. And it's why they start smoking when started. Oil runs down the valve stem after you shut them off and sets on top of the piston until you fire it up.

Even if not broken up and missing valve seals that have hardened will start to wear on the stem allowing oil to get past the seal.

My 25hp Kawasaki smokes when it's been setting a while and does so for about a minute then quits. It's not using any oil so I'm thinking it's time for seals.

[nobuckbuild]

yamaha engines are generally bullet proof except for rings and seals and most of the time the cylinder is fine and just needs a light hone to take the glaze off get a ring and gasket set and maybe clean up and lap the valves into the head some and run it till it does it again , at least thats been my experience with them 100-150 rebuild and your good to go and abuse it for another 10-20 years , and thats only if you care about the little oil burn , i've seen some run like that for years on end , also before you do any of the things you have done so far i would have changed the oil because sometimes you get a fuel issue where the carb starts dumping too much fuel and the oil gets thinned down and all of the sudden you have a smoking problem , then you change the oil and the problem goes away for a while , thus indicating that you have a float or jet issue and remember yamahas are strictly one quart oil only

[palongee1]

Thanks for all the input, I was able to get the other seal of with a little prying, I don't know if its gonna be a fix but its cheap enough to try before I pull the motor and split the case. The cart doesnt get used much this time of year so its a good time to get it fixed one way or another, when this thing crapped out on me a few years ago I was lost without it around my place...Anyhow, I just got called in for a 72 hour shift so I won't get to screw with it for a few days, I'm hoping the local shop has the seal and a head gasket, otherwise ill be staring at it until I get parts :) Thanks again for all the input! Ive got the rzr for backup in the meantime, it just doesnt have a dump bed

[palongee1]

Thanks NOBUCK, I did drop the oil and refilled with 1 qt only, aI also had adjusted the valves and freed up the little one way vacuum valve and replaced the spark plug...ive been messing with it the last couple of days, however, it seems it was the next start after freeing the vacuum valve and a new plug that it really started to pour smoke, however after filling my shop with smoke I moved it outside and ran it for a few and it cleaned up after a few minutes, then this morning it was smoking like hell again, Ill get to the bottom of it eventually...I did have an issue a couple years back where I wasn't getting any fuel, I figured out the line from the front of the block that tees off to the fuel pump had some oily sludge in it, I blew that out and haven't had the same problem since....the saga continues :)....