Tower Hobbies 75 engine is looking good! I bought one of these to try, as I wanted an inexpensive power plant with more punch than a 60 for my new GP Stuka 60. The recent comparison tests of the 60 size engines also placed the Tower engines in the top as far as power and price. For $10.00 more than the 61 I went for the 75. There are the usual production issues. The throttle barrel wasn’t turning smoothly and seemed to be scraping. I removed the throttle barrel and found slag at the bottom of the throttle barrel. I polished it out with a Dremel polishing bit and it now operates smoothly. The next problem is that the muffler bolts mount from the muffler side into the engine casing. This means that in order to tighten down the inside bolt I had to cut down the L part of an Allen key. It is also true that the engine is very tight out of the box and in order to get the engine to turn over the first time, you need to heat up the head with a heat gun immediately prior to starting. Once you have a tank through it however, it will turn over the same as other 60/75 engines. During the first tank run the muffler bolts and the fast speed idle screw assembly started to come apart. I used lock tight on the needle valve parts and shake proof washers and lock tight on the muffler bolts to solve these problems. I used a Kaos 60 for the test bed with impressive results. The engine starts very easy, has tremendous power and transitions well. With an APC 12-6 on the nose I tested the vertical to see how far it would go. I had to stop the test, as there was no sign of the plane slowing down and I was losing sight of it on a clear day! I checked the fuel usage on a 16 oz. Tank after a high speed 8 minute flight and was happy to see that it had only used about ¼ tank fuel! Good power and fuel efficient as well! I made a slight carb adjustment for my second flight on the Kaos and the engine ran just as smooth but had a lot more power. I am now confident that this engine qualifies as a reliable and powerful warbird engine!

Tower engines are USUALLY very powerful engines. As you have noticed though, QC does need some attention.

The PRIMARY problem with Tower engines are air leaks. The backplate and carb are quite common. The other airleak (shows up on about 75%+ of the engines ) is through the front bearing. When you try to shut the engine down with the transmitter, the engine continues to run for 30 - 45 seconds (or longer ).

So far it sounds like you have one of the good ones.

As someone in the process of building my Trainer, that post scares the castor right out of me. When I finally do get a glow engine, is it inevitable that I'm going to become an engine technician?

Time Pilot
Yup. But tuning an engine is a skill no different from selecting a proper electric motor and prop for the size batteries you are going to use. Either skill requires that you learn what is needed. Electrics require familarity with a voltmeter and ampmeter, fuel requires tank and needle valve skills. Just different strokes.
John

Time Pilot,
Actually, having to "debur" the inside of the carb barrel is pretty rare for most engines, as is having to worry about air leaks around the bearing or the backplate.

Get yourself and OS 46 FX (or AX), or a Thunder Tiger 46 PRO, or an Evolution 46, and you won't have to worry about that stuff.

You WILL need to learn how to tune one of these things, but it's really pretty easy once you've actually "heard" someone tune one. Until then, all the written advice in the world can't quite describe the sound you need to hear when tuning. []
Dennis-