Man oh man you guys are gonna kick my bu** when you hear this. Okay, so I drain the gas out of the BCS walk behind tractor and bring it into the garage to dismount the engine. My buddy and I unbolt the engine and it comes off with the dry clutch attached. We notice that there is a lot of grey aluminum shavings inside the case...hmmm. We look closer and staring back at us, hanging out of the clutch is this 2" long set screw that has come loose, backed its way out and is grinding against the inside of the case. This caused the screeching, the stalling and the grinding feeling when turning it over. How putting MMO in the cylinder freed up this *seize* is a mystery to me but at the time it sure seemed like it did. I was happy to find this cause it meant that the engine is still good. The next day we got hit with a snow storm so I rushed to put it back together. The set screw got a few drops of LocTite blue just to be sure it dont come out again. Actually I was a little over zealous and broke the allen head on that set screw when I tightened it...hope I dont have to take it out. I also managed to cross thread one of the 4 mounting points on the engine pto side, forgot how delicate the cast aluminum threads are...mixed up some 15 min epoxy and put the bolt back in. By the time I got her all back together there was 5" of powder snow on the driveway. I put gas in the tank and she fired right up - not having the drag of the set screw cutting a rabbet into the aluminum case sure helps things a lot ;-) . It works fine. Thanks to all of you for all your help and suggestions expecially *mownie* who said back in the beginning "....Check the components that deliver the engine power to the wheels and make sure something there is not seized or locked up before you devote all your time to the engine per se." Maybe I got lucky with the set screw backing out and causing all this. It sure prevented the engine from seizing up due to gas diluted oil and now I know how exactly gas in the oil can ruin an engine. In addition, I know how to go about rebuilding it and have looked through the B&S rebuilding steps on their web site. This isnt the same as the experience of actually doing it but its something. Thanks again, Tim

If you read my post again you will see that I said "And you should never run the engine at less then full speed unless you are sitting still. Hydro pumps, blade tip speed, etc are all engineered to work best at full throttle and you will help keep the engine from building up carbon." I did NOT say that running an engine at less then full throttle will build up carbon. There will be normal carbon buildup in any of the engines used in lawn and garden equipment. Lugging a tractor around at lower engine speeds for an extended period of time will build up MORE carbon then if it is run at full throttle, especially under a load such as with the blades engaged. If you feel a need to run your engine at 2800 instead of the factory set 3600 then that's your choice. While I am far from being some type of know it all, super mechanic, I have been working on this type of equipment/engines (at 3 different businesses that deal in various brands such as Snapper, Toro, Exmark, Lawnboy, Scag, etc) for about 18 years so I have seen a thing or two. So if you believe that running an engine at 2800 instead of 3600 is better, then I guess it is I that is all ears.

Thanks Bill and Walt. Walt it's been a few years since you sent me directions on how to change the head gasket on a Husqvarna/B&S tractor I had. Job was easier than I expected and engine ran great for the 2 addition years I owned it. So Thanks again. I'm a little confused about the current problem. Theres no smoke so does that indicate the head gasket is OK? Are Vanguard engines prone to head gasket problems with such low hours? I have 205 hours on the engine. I'm going to wait till tomorrow and change both spark plugs. Hopefully that will solve the problem. Hopefully. But Bill I'm confused. If I disconnect the spark plug wire (one at a time) and ground it and mow what could it tell me? I'm guessing if it runs the same that is badly on one side and dies on the other it means thats the side with the problem. Does that prove it's an ignition problem? Or could it also be a fuel problem on that side? Like I said I'm confused. I actually like working on small engines unfortunately I don't do it much and I learn as I go. Thanks again guys. Jim

First, pull engine shroud sheet metal, clean fins and chk for any hidden wire damage. then next time if it still cuts up, stop and check right away for spark to both plugs.If you are still getting a nice hot spark to both plugs, may still have a fuel delivery prob. that could mean checking the entire fuel line back to tank, replacing any soft/cracked lines, new fuel filter, gas cap vent cleaned and possibly another serious carb cleaning along with draining all old fuel outta the tank and replacing with fresh... And mebbe Walt will drop by with some of his sage advice..