Since I have never used a 60/90 sized engine before. Just want to know how much more powerful is the G90 compared the G61 ring/ABC. I have read the specs so this is more of a real world use question... is there an enormous or only a slight difference?... I plan on buying one of these engines to put on the Tower Uproar 60 and GP Extra 300S .60.
Thanks

The peak horsepower rating of the SuperTigre G-90 is about 3/4 Hp more than the G-61. The main advantage, though, is that the .90 will swing larger propellers. We'll run a 12 x 8 to 13 x 7 prop on it. The .61 likes to run 11 x 7 or 8, or 12 x 6 or 7.

Thanks for the prompt reply....So the G90 is definately more powerful. I guess I'll be getting that one. As for the prop size... I've seen a lot of guys using 14x6s or even larger props on this engine ...isn't this really bad for the engine...overloading? Personally I was thinking 13x6 for sport/aerobatics and 14x4 for 3D...what do you think? and oh yeah will it be as happy running a 12x6?

The main t hing is RPM. Prop the G-90 to run between 11,000 and 12,000 RPM and it will be fine.

Thanks again Bax....but here's a new problem... I noticed that you also answer questions about OS engines....
Since I live in India and things are rather in limited supply here.. the only engine readily available is the OS 91FX....now I have read a lot of bad things abouth this engine, concernign the needle valve and bearings... there are claims that OS has since fixed the problem and the engine is as good as the next in their line up... is this true? How does this engine stack up against the ST G90 in terms of power and relaibility/longevity? Due to the import duty we have to pay about 50% more for a given product ... so will my money be well spent?
As for the propellors all that is availabele in the 13 and 14 inch range are the master airscrew K-series 4 stroke ... will these be ok on a 2 stroke engine?

Thanks Bax... I posted this once before but it didn't go through. Since you are also connected to OS engines....

I've run into a bit of a problem...here in India the choice is rather limited so ... the only engine available is the OS 91FX.... I have read all that is availabel on this engine on RCU untill my eyes beld...I'm just concered about the quality issue regarding the needle valve and bearings....As per the posts OS has fixed this engine... so is it a good engine?..how does it stack up against the ST G90 (my first choice) in terms of power and reliability/longevity? Please bear in mind I have to pay 50% extra due to the import duty...and wouldn't want to buy a lemon.

Secondly again due to limited choice the props availabel in the 13-14 inch range are the Master Airscrew K-Series 4 stroke.. are these ok to use on 2 stroke engines?