I've owned this Troybuilt tractor with a B&S 18HP for about 8 years now and have been having problems with it now for about 4 years. What I thought was just the batteries going dead is now very questionable. Just this past summer I bought a new battery and it worked fine for about 2 months but again the engine will not crank over, I mean it will move but it comes back to the same position without revolving once. It's like there was too much compression so what I did was I loosened the oil dipstick and pulled it out about an inch and then tried starting it and it turned over and started like no tomorrow.

So my question is what would be causing this pressure build-up inside the crankcase that's so high it will not allow the engine to turn over at all even with trying to jump starting it with a car battery?

This is an Intek OHV 18HP engine with 90 hours of use, new oil this past summer.