congo_181

I am trying to rebuild an old OS FS-61 four stroke engine.

It used to run, but the bearings were very worn, so I have replaced them.

Can anyone help me with the carb though.

It is an air bleed type carb, but has no identificatoin on it.

It has main needle, air bleed needle and another (throttle stop?) adjustment.

I have no experience with air bleed carbs, and have no idea of the setup for it

Any help gratefull revceived...

Jim

Bax

My Feedback: (11)

When first starting an engine with an air-bleed carb, open the high-speed needle about 2-1/2 turns. Adjust the air-bleed screw so that the air-bleed hole is blocked by 1/2. If your carb has an idle stop screw, adjust it so that the carb will stop when it's closed to about 1/16"-inch or so.

Now you can choke your engine, start it and open it up to full throttle. Adjust the high-speed needle as necessary. Retard the throttle to work on the idle. To richen the idle, you turn in the air-bleed screw. To lean it, you turn it out. You adjust the idle stop screw as necessary to get the idle RPM you want.

Please remember that you can set the idle RPM too low. You'll find this out if throttle-up is compromised. You may have to give up a few RPM at idle to get a good transition.

congo_181

thanks for the reply bax - its the arbitrary part of the air bleed that is getting me...

The air bleed part seems to make no difference at all right now, but i suspect the compression is low anyhow.

I'm going to change the piston and ring and then try again...