I have a Tower .75 and I have a really hard time turning it by hand. It gets stuck on the top of the stroke (without glowplug installed). I was wondering if this is normal. I have used some fuel to lubricate it and loosened and retightened(looser now) some of bolts and now it turns over with some effort. Is this normal?

Yes this is normal. In fact, that's exactly what you want until it's broken in. It's caused by the cylinder tapering at the top of the piston throw, providing a leak-free compression seal. A word of caution, however, don't try to turn it over too much until it has been run and broken in. I even used a heat gun to warm up the cylinder just prior to it's first start. Break it in and it'll diminish and provide you with a great running engine.

I doubt I will ever understand why some people like to turn over a brand new engine (I see it all the time in the hobby shops). I guess it has something to do with the metal-to-metal grinding that gets people off...

I don't like to turn it over that much :-) But when it got stuck (and I mean STUCK), I was concerned that it may bend the con rod when I try to turn it over with a starter.

What do you think? Good excuse? :-p

Ed, Thanks for the explanation and word of advice. I will try to warm it up a bit before I start it for the first time.

I have broken in the engine now and it seems to run with really great authority, I think once it is leaned out, it will be able to hover my 8lb plane. However, I have one questions, right now I am using a 12 x 6 apc sport prop. At full throttle, the engine is turning so fast that I feel that it's going to rip the plane to bits and pieces. Of course there is also a lot of vibration. I didn't tach it (silly, the spinner broke off after the first flight and I couldn't get it started again) but I wonder if I should be running a bigger prop to slow it down a bit. Does running too small a prop cause any problems?

By the way, the engine was a pain to get started the first time because of the "interference" fit. That's what killed the spinner. The engine jammed so many time and made a terrible terrible sound each time and upon first start up that everyone was like gawking at me and making me feel like I had just committed cardinal sin. Anyway, the engine is sweet now... just what prop?

Yes, the 12X6 is too small for this engine. This engine runs great with the
Master Air Screw 14 X 6
APC 14 X 6
My favorite is the APC 14 X 4W. This prop is kind of expensive, but has lots of thrust.

Thanks... that's EXACTLY what I wanted to hear...

Can I say, this lump rocks!

Yes, that lump definitely rocks. I have been using a Tower 75 for 15 months
now, and am very pleased with this engine. Lots of power. No problems at all.

I might add to my previous post that the APC 14 X 4W will decrease the speed
a little, and will also act as air brake to some extent. I like that, since it keeps
the plane from floating on landing, etc. You can buy this prop for $10.00 U.S.,
from the hobby shops, or order directly from APC for approx. $12.00.

I have already gone out and picked up some 14x6 APC props for this weekend flying... it's going to be sweet!

As for the "W" prop... what does the W stand for? Wide?

I have a Tiger Shark 75 on a Cloud Dancer 60 and use a APC 13-7 with good results. [8D]

Forestroke, you are correct, the "W" stands for Wide.
I guess thats why it has some braking action to it.