Hi all, curious if anybody has any experience with GMS 2 stroke engines. I am now back into
this hobby after a 9 year absence and my current Sig Fazer has a Super Tigre .45 ABC and I
love it. However the GMS engines weigh less but wondering if they are as powerful/dependable
ect. as a good ole Super Tigre? Is the GMS worth the weight loss???

Thank you for any input.

The GMS 47 is a very powerful engine. Its actually made by the same company that makes the Super Tiger but there are no parts that will interchange. The GMS is not any less powerful than the Super Tiger.

Enjoy,

Jim

I have a GMS 40 and GMS 47. I think they are both great and would purchase another if needed. The 47 has tons of power. Other pilots are always asking what I run after they see it go. It idles very low and and has lots of thrust when wide open. Both the 40 and 47 have the same block. The 47 has a larger bore. I did have one problem when I purchased the 47. My 40 was running great but I just couldn't keep the 47 running more than a few seconds over 1/4 throttle. One of the guys at my field said it seems like an air leak. Upon further investigation I noticed on my 40 a small red washer (gasket) used on the carb barrel set screw. The washer was missing on my 47. I went home, cut a washer from a sheet of gasket material I had, replaced the screw, and fired up the engine. It worked right away and has never had an issue since. This is no fault on design, someone just forgot to put the gasket on before shipping. So, I'd say check that out when you get yours and have fun. I ordered from mecoa.com. Send them an old engine with no missing parts and they give you $20 off.

One other note, seems like my 47 is kinda quiet compared to other 40 size engines. The pipe is a bit larger than most.

-Rocko

SD,


You can search RCU on that subject.

There have been threads that illustrated problems with crankshaft-crankcase fit (oil and air leaks) and with carburettor problems, in GMS engines.

As far as bang-for-the-buck is concerned, they seem pretty good.

Thanks, there is a guy at the field with a few of them. Actually the club pres. He swears by them and
has a new plane all the time with one on it. But when he flies I notice they hesitate or cough and then
go. Maybe its how they are tuned and he likes them that way.

I am considering these because I am tired of the heavy super tigre mufflers, if you want to buy a
aftermarket muffler they are about 30 dollars. So that would put the motor at about $100 for a
40ish size. That is rediculious, I will consider a 4 stroke before I would do that.

I have the GMS .76, .32. and the .47. The .76 is on my Four Star 60 and the .32's are on my Twinstar and the new .47 is on my Four Star 40.

Some of the GMS engines have an issue where they won't shut off when you close the throttle, but I am very pleased with the performance of these engines. I read an article that claims the reason the engines won't shut off is because the clearance is a little loose between the front bearing and the crankshaft. I did take my .76 and .32's apart and put a little locktite on the front crankshat and it fixed the problem on the .76 but not the .32's.

Hope this helps.

My .47 came with a slip of paper that said the motor may not shut off when the throttle is closed and is designd that way on purpose. It said this was to allow a lower more reliable idle. With that said, after several flights, both my .40 and .47 shut off fine when I close the throttle.

-Rocko