Thorp Air Command - T18.net

I have a new carb and I had it out of the box the other day and moved the throttle arm and fuel shot out. I am guessing its leftover fuel from when they test ran the engine? But it got me thinking, is there anything I need to do to the carb prior to installation on the engine (like flush that out)?

Also, anyone care to give a rundown of what needs to be done in order to properly set the rpms on the carb, or other carb install items I should address?

Hey Ryan - others may chime in with what they did, but when I installed mine last fall, I just bolted it up - it was a rebuild out of the box - as far as the idle screw, I started with 1.5 turns out and it worked pretty good but ended up adjusting it about a quarter turn out after experimenting and I can idle about 700 RPM smoothly - am running conventional bendix mags. SO far so good once I found out about the vent issue making me run intermittently lean at high speed/high RPM.

Before you bolt the carb up make sure it has the lastest AD for the "Blue" epoxy float . If it a new carb it should have the blue float...check the paper work that came with the carb . If you are concerned about the fuel in the carb you can remove the drain plug on the back of the carb and drain it . The only other thing you might want to check is the finger screen on the inlet side of the carb . Probably not necessary if the carb is "new ."

After the carb is bolted on , run the engine to normal temps and during shut down see if the idle cutoff rise is the required 50 RPM increase when the mixture is moved to
Idle/cut-off ." If not you will need to adjust the ground idle mixture screw on the back of the carb . I am assuming it is a MA-4-5 ? The MA-3 should have a similar adjustment screw . The screw is labeled "Lean/Rich ." I can't remember which way to turn the screw if you don't get the 50 RPM rise ? SOOO may screws sooo little time ! You can Goggle for that info . If you don't have it , it may be a good idea to get a Marvel/Precision carb manual . You can get them off the web for free ! After you get the 50 RPM rise you may need to adjust the ground idle to get the 650-700 RPM . Mine runs smooth at 650 RPM .

You can read some of my prior posts regarding the carb problems I had , including an uncommanded engine shut down crossing the numbers at KSEE .

RB

ok, I can handle that. thanks for the tips.