supertux1
Heliman
Location: Madison, WI
| I bought one of the OS .91 C-Spec Pump engines a few years ago.
After fighting with it for a year like everyone else, I bought
a cheap used 3 needle carb from an OS .70 and retrofitted it on.
I got a new backplate too, and removed the pump. It doesn't lean
out in flight anymore, and it's a lot more fun to fly this way.
I'm just wondering if I'm getting all the power I should be getting?
Have I been spoiled by the sheer power of the OS 'too lean' runs?
I play with the needles constantly to get more power, it's not underpowered by any means, I'm just greedy and never satisfied. 
(Running 8.27 gear ratio w/MP2, 1850 RPM, mid needle 1 turn out, high
needle 2 turns out. Two shims in the head.)
Sometimes I get antsy and turn the high speed lean, and I'm happy with it only to find that I fried the glow plug on the next flight.
(I recently bought a viperhead and a carbsmart and will be fitting those shortly.)
In my parts box I have a one-way fuel valve and the old backplate with the nipple on it. Would it be any advantage to run crank case pressure back to the main tank through the one-way? Would one of those $30 tower hobby perry pumps work with this?
I've heard about the $200-$300 OMI mod, but if I'm spending more money on this engine it will be to replace it with one of the newer OS .91's |
