taildragger101

My Feedback: (2)

Need some info on how to tune carb on old OS 60 H. Thanks

rainedave

My Feedback: (1)

The original had an airbleed type. Set the airbleed screw so that it covers up half of the small hole in the front of the carb body as a starting point. Airbleeds work the opposite of high speed needle valves. Turing the screw clockwise richens the low speed setting and turning it counterclockwise leans the low end.

I would set the high speed needle at around three turns out to start the engine. This will be a rich setting. Then, gradually turn the needle valve in with the engine at wide open throttle. Once you get that needle set, you can optimize the throttle transition by either leaning or richening the airbleed screw.

David

taildragger101

My Feedback: (2)

This carb has a main needle adjust and a adjust in the middle of the throttle barrel that just covers the ventury when you turn it a half turn.

rainedave

My Feedback: (1)

What is the number on the front of the carb body under the OS logo? It sounds like it's a newer replacement.

Harry Lagman

Is that the "7B" carb on your engine? The 7B (a two needle carb that was also fitted to the early FSR .60s) was the OEM unit on the late model Max H FGR with the black cylinder head.

proptop

My Feedback: (8)

Sounds like you have perhaps a Black head?
IIRC that idle adj. also adj. the mid range.
You adj. the idle by turning the screw in very small amounts...and the mid range with complete 360 degrees turns in or out. Obviously the fuel delivery slot needs to be uncovered...and the engine won't run if the low speed adj. screw is 180 degrees out of adj.

Don't know if I "explained" that properly/clearly?

Edit: Harry beat me to it...

rainedave

My Feedback: (1)

Is this the carb you have? I actually have one on my 60H.

David

taildragger101

My Feedback: (2)

Sorry I didn't get back sooner, just got home from work. The carb is a os74 on the front of the case. You guys are on the right track but the adjustment in the middle of the spraybar does not move in and out, just opens and closes the port. Hope I am making sense.

rainedave

My Feedback: (1)

That sounds similar to the way the #7L works. Does it look anything like this?

David

rcdude7

My Feedback: (264)

That is the same carb that came on my .60 FGR blackhead. It looks like a typical two needle carb, however the low end metering looks like the setup on a perry carb, full lean to full rich in a quarter turn.

rainedave

My Feedback: (1)

I'd like to see a photo of this carb. I don't think I've seen a 74 before. Was it only used on the FGR Blackhead?

David

proptop

My Feedback: (8)

Oh...o.k....I think I remember now
You can turn the brass low speed screw round and round and it doesn't make any difference (move in or out ) it just uncovers the spray bar slit...the brass idle/low speed is a tube with a cut away portion that slips over the spray bar.
It took my buddy and I while to figure that one out...his was on a Black head (many moons ago ). We just fiddled with it until we got 'er to run.

I'd say try test running it and just "wing it" (bad pun intended ) [)]

Maybe Bax has the paper work or sumpthin'? (sorry I'm not helping much here...)

taildragger101

My Feedback: (2)

Proptop, you got it, thats what I got. Things about impossible to get to run right. Didn't know if anyone had any tricks. Thanks for all your help.