My only complaint on the Tower .75 is the muffler mounting, which requires you to grind down the short arm of an Allen wrench to squeeze it behind the muffler barrel. Taking the muffler off & on is about a 30 minute tedium. Get yourself some Ultrathrust Copper hi-temp sealant in the auto parts store and smear a bit on the muffler joint, put a drop of threadlock down the screw-hole and use a split lock washer on muffler mounting screws.

Also, when I was breaking in the Tower .75 the muffler blew apart on me, made a mighty roar and woke me up good. I found the end bell about 50 yards away, gathered the other pieces and put it back together. The rod that holds the end bell on is threaded at the front end and turns into a tapped hole on the inside of the front bell, which is aluminum. The steel rod just stripped the threads right out of the aluminum piece. When I put it back together I drilled out the front bell with a hole clean through, substituted a 6-32 threaded rod from the hardware store, slightly longer length, and put nylon lock washers at front & back. That held up just fine for the rest of the season. Use the Ultrathrust sealant on the muffler joints too.

Aside from these petty annoyances, the engine is great value. Tunes up nicely, runs well at top, bottom & middle. I think mine liked a K&B 1L plug.

Please don't fly your Javelin at full throttle all over the place. With this engine, probably half throttle for straight & level, three quarters for up-lines and full maybe for up-line snaps. The nice thing about this kind of "over-power" is you'll be able to get the same performance with 10-15% nitro that others get only with 30% nitro (at maybe twice the cost per gallon). Saves a lot of fuel money over the course of a season.