200 YTH2448 - Several issues

[MichFish86]

Thanks for the additional replies. Flyin2low- thats good to know about the valve guides. I'll keep that in mind, but I'm hoping for an easier solution.

detel - The air filter looks pretty good.

What else could cause plugs to blacken after only 30 minutes of running? I really feel like this might be tied to the big backfire, but maybe not. Anyone agree that it could be the bad valve guides? I'm hoping for somethings I could try to check on in my garage instead of taking it to a mechanic. I'm fairly handy with smaller, push mower sized briggs and stratton engines, but I don't know much about this v-tek.

 

[MichFish86]

I was just out running the mower for a few minutes and I realized that I forgot to mention that there is a "pop" or "Poof-poof-poof" sound rapidly, especially once it warms up a bit. The sound is not in a regular pattern - "poof---poof-poof--poof". Sounds like it is missing or something because it seems to slightly loose power each moment that it "poof"s.

 

[I-75]

I have the same model and insane smoke/issues. I read what a respondent said about adjusting valves and have heard the same suggestion locally. I think it's crazy that these Briggs units have so much issues with smoke. I wish there were non cost-prohibitive way to repair this. All I ever hear locally is it's cheaper to buy a new mower.

 

[MichFish86]

An update: I haven't posted on this for awhile because it took almost 3 weeks to get the mower back from the mechanic.

The mechanic cleaned the carb which helped the mower a lot. It is much more power and it made the bigger problem come into focus better. Obviously the mechanic didn't test it long enough because if he let it get hot he would have noticed the problem.

Now the mower runs perfectly until it get hot. Once its hot it starts blowing white smoke (burning oil?) and missing. What would make a mower blow white smoke and miss only when its hot??

Thanks again for lending your expertise.

 

[Fish]

Sounds like you have a head gasket that is starting to blow. Remove both valve covers and push out into the yard and start and run on low. Oil will drip out where the heads are off, and you can visually see if you have a bad head gasket, as it will be apparent where the compression is escaping.
What happens, is that the escaping compression goes into the pushrod gallery which goes into the crankcase, and forces oil into the breather then carb.

 

[Fish]

They almost always blow in this area, as there is a huge gap between the head bolts and not much gasket area.

 

[MichFish86]

Sounds like you have a head gasket that is starting to blow. Remove both valve covers and push out into the yard and start and run on low. Oil will drip out where the heads are off, and you can visually see if you have a bad head gasket, as it will be apparent where the compression is escaping.
What happens, is that the escaping compression goes into the pushrod gallery which goes into the crankcase, and forces oil into the breather then carb.

I thought this was a great suggestion so I went ahead and replaced both the head gaskets. I figured it was due anyway at 450 hours. Unfortunately, both the head gaskets looked good and after reassembling it with the new gaskets, the mower is still burning a lot of oil. I also adjusted the valve clearance while I was at it. Any other ideas for why the mower is burning a lot of oil? Its going through about 1/2 qt per hour. Again, it only starts smoking once it gets hot.

While I had it torn apart, I noticed the left cylinder had way more carbon build up. Also, the left cylinder has 2 black valves, while the right cylinder had a white exhaust valve. Therefore, I think the oil burning is coming from just the left cylinder.