What is the correct breakin procedure for an gms .61 engine? There was no instructions with the engine and I want to make sure the normal way is correct,as this is my first ringed engine! So,any help will be great!!!!!

Thanks

When I flew with glow engines, I would run them rich until broken in.

How did you know it was broken in?
I am not trying to be flippant, what changes to indicate you have reached this mechanical nirvana?
KW_Counter

There are lots and lots of threads on this one. A serch will bring in tons of them. Basicly you need to run it very rich for a good while. Maybe 6 tanks or so. Keep the rpm's down to half throttle or so for the first 3 or 4 tanks. After 6 tanks or so start leaning just a little each tank full. At around 12 tanks or so you should be ready to go. I know this sounds like a lot. but the rings on these engines is small and kinda delicate. They have to be gently broken in. Once broken in properly with a little care they will last a very long time. Good luck with your new engine.

Mark Shuman

Both the above posts assume the motor is ringed, not ABC.

Are you sure? If it is ABC, the technique is quite different and explained in detail in other threads.

My question was not how to do it. There are many threads and instruction books for this.
My question is how do you know if an engine is broken in or not?
KW_Counter

It is broken in if it holds a good idle and run the same every time without haveing to adjust the needle all the time. My well broken in OS 25 FSR needs 2 adjustments a year, once in the spring, once in the fall

I just got a new Supertigre G40 today. I was reading breakin instructions for it. It says get it started, run for 30 sec and then open to full throttle and let it run for 5 minutes, pinch the fuel line. If it rpm increases, turn needle valve in 1/8 of a turn, let it run for 1 minute, the pinch the fuel, etc. When you pinch the fuel line with no increase in rpm, then richen 1/4 turn and let run for a few minutes.. Says it should be done in two tanks. How does that sound.

MuffinMan,

That sounds exactly like the instructions for my Tower .75 I just got. 2 tanks and it now holds RPM and is ready to fly. Turns a 12x7 at 12,200 rpm on 10% powermaster.

Later!

Racer,

Your GMS is a dyke's ringed engine. At least from the [link=http://www.mecoa.com/gms/specs.htm]source info[/link].
It needs a very rich, four-cycling initial break-in; 10-20 very short runs (10-30 seconds), with complete cooling between them.

This, to anneal the cast iron ring in the steel sleeve. With a dyke's ring, you don't need this break-in to be too long; about 30 minute should be more than enough. After the short cycles, give it 15-20 minutes of continuous four-cycle (two tanks) and it should do it. After this you should check if it can hold the needle. If it does, you are done.

If not, give it 5 more minutes rich and try again.