OS fs-91 surpass running problems
 

I have a relatively "new" engine (run only about a gallon 'till now" that was resting in a box for app. 3 years.
Trying to bench-run it I found out that the engine will start only at WOT position, and will cut-off immediately when lowering the throttle below WOT.
Main needle valve was set to 4 full turns, and the mixture control valve was opened 2.5 to 3 turns.
Fuel level was at carb centerline and fuel was 15% Omega 4 cycle fuel

Help!

Any response will be more than appreciated

Thanks in advance

Yaron

RE: OS fs-91 surpass running problems
 

It sounds like the engine is just too rich to accept the throttle. You need to get 15-20 minutes of running time on the engine at full throttle, and then start to lean it towards peak RPM. After about 40 minutes of running time, you should be able to lean the engine to the point where it's just rich of peak RPM. Then you can retard the throttle and start working on the idle mixture and RPM settings.

RE: OS fs-91 surpass running problems
 

I've got the older OS 91 surpass just like your's. mine's inverted on a GP spacewalker, I know that GP's directions say to mount horizantally, but I didn't want to cut up that cowl so I opted to run it inverted, anyway, My engine is so finicky, i have tried adjusting both needles, and just can't make it happy, when the igniter is on it idles great, when i turn it off then it lose's rpm's at idle and sometimes dies, i can also get it to run at wot, but it just doesn't seem to run smooth, Am I gonna have to install an onboard glow igniter or does the carb need to be reworked, I checked all the O-rings and they all seem fine, the low speed needle, I have by accident figured out is very sensitive, where should it be to have a good starting point, also what would be the best plug for this mounting configuration?? I have a new f plug in it , but i didn't know if there's anything hotter?? what would be an acceptable prop, I have a 14x6 on it now?? Thanks for all the help

RE: OS fs-91 surpass running problems
 

Thanks Bax

I'll try it today

Yaron