martenson

I have a GP Stuka with an inverted OS 91 4 stroke, and the engine works good on the teststand but not in the plane.
If I unhook the glow it wont run, if the glow is on it works decent.
I use OS fourstroke glowplug, is this not hot enough.
I have leaned it out on the idle screw and it does not help.
Should I try a hotter plug??

Thanks

parrthd

you may have leaned the idle screw out a bit too far.....

o.s. manual states 3 to 3 1/2 turns out as a starting point.

if needed...try the manual on their webpage.

[link=http:///www.osengines.com/manuals/fs-70s-ii-91s-ii-p-manual.pdf]FS91 Manual[/link]

martenson

parrthd: thanks for the link, but I think my engine is to old for that instruction, I have a small adjustable brass center screw in throttle arm that's for the idle.
Bought this engine second hand and no instruction, I have cleaned the carb and it runs good upright in the test stand.
So my though was that it got rich upside down on idle and I might fix it with a hotter plug.

I have been absent almost 20 years from this hobby and I'm relearning stuff all the time.