Hey thanks Walt! I am hoping it's head gasket versus piston/rings. I will order the head gasket. Unfortunately, I have another issue to fix first. When I was taking off the flywheel to take a look at the oil breather reed valve, I used a backyard method to pulling the flywheel (instead of using a puller). Well I ended up stripping the last 3 threads on the flywheel bolt, which is no problem becauase getting another bolt is cheap. The problem is that I slightly damaged the 1st 3 threads into the crank. Do you have any suggestions as to what to do at this point? (other than buy a new crank $167 from Briggs). I was thinking about possibly using oil and a new bolt to see if it will turn in. I can still see threads in the crank but the 1st three look a little damaged but I can still see their grooves. The bolt, however, was totally destroyed at the last three threads (no grooves). I'm thinking that the bolt is softer and will strip before the threads in the crank to prevent idiots like me from stripping out the threads in crank, when they are too impatient to wait until the next day to buy or borrow a puller!

Yungman, Don't use multi-vis oils in a mower. Multi-vis (10w30 etc) are for cars, and water cooled engines which get started up in cold weather and have to run in a variety of temperatures. Air cooled mower engines run hotter than water cooled engines. The internal tolerances are designed to be looser at cold for this reason, so that when the motor heats up, the tolerances close up under normal running temperature. Multi-vis oils will seep past the piston rings when the motor is warming up. You will get more smoke and oil burning with multi-vis oils in mower engines. Most mower engines don't get used below 40 degrees (with the exception of snowblower engines), so straight 30W is recommended for most air cooled mower engines. In Texas we do have high temperatures, so I frequenty use straight 40W when it gets 90+ degrees here. While I'm ranting about oil, the owner's manuals always say 25 hours as the oil change interval. But that's under normal conditions. When it gets dusty and hot (like the 90 degrees above), forget that 25 hours, go for more like 10 or 12 hours sometimes. Remember these little engines usually don't have oil fiters, so whatever gunk that gets in the oil, just goes round and round in there, grinding away at the parts. With oil:When in doubt, change it out.

***"When I engage the mower blades I notice a puff of black smoke from the exhaust area. It doesn't smoke when I am mowing, only just as the blade engages. Is this a problem?"*** Absolutely NOT A PROBLEM. What you are observing is simply a result of the engine governor "snapping" the throttle wide open, for a moment, as it reacts to the drop in RPM caused by "applying the load" of the cutting system to the engine crankshaft. The sudden loss of RPM causes the governor to try to increase the RPM to its former rate. The governor attempts to raise the RPM by opening the throttle plate of the carburetor. This action, in turn, will allow a greater volume of air to enter the engine, along with the greater volume of air, comes a lot more fuel drawn from the main jet. At first, the volume of fuel is great enough to result in a "rich mix", which is why you see the puff of black smoke. The engine quickly recovers its RPM and once it reaches its former RPM rate, the induction mixture has pretty much "leaned out" to a near optimum air/fuel ratio. If the load applied to the engine was greater than what the engine could handle, the governor would still open the throttle but instead of seeing a quick puff of black smoke........you would see a continuous plume of black smoke as the RPM got lower and lower til finally, the engine quit running.

Make sure you neutralize the pressure in the room its in by opening a window, if you dont have a pressure problem in the house you may need to extend the chimney. You are on the very cusp of the manufactures minimum rating and you have that longer then average offset..I think thats most of the problem. You extend the chimney buy using a anchor plate and a transition plate. The transition plate would be optional if you have a good way to attach the anchor plate to the current liner. Normally it would be installed like this: Transition plate covers the chimney and the flange for connectiong the liner points down the chimney The anchor plate bolts to the top of the transition plate and provides a connection for the class A chimney,. If it wouldnt look too rediculious i would add 4 more feet. If you have a negative pressure problem in the home, (if cracking the window improved things dramaticly) then you have a complete other set of problems to deal with. go to www.duravent.com and look up the three parts. You will need the transition plate, the anchor plate, and what ever length of pipe you need. This is a whole nother can of worms, but the stove might perform worse in the basement. There are absoluty no guarentees that your basement will provide a better installation then what you currently have. To make a long story short, your house is one large chimney, heat rises in the attic positivly pressurizing the attic, the main level of the home is is a pass through point, and is typically neutral, and the basement is the supply, wich is under pressure because there isnt much air that can get in the basement, making it negative for pressure. That means the new chimney that is way up in the air has a pretty postive pressure at the top, and the stove at the bottem is in a negative room, and becomes the appliance that tries to neutralize the basement. The stove could be thought of as the same effect of opening a window to neautrlize a room. You can imagine the potential draft problems...