Dolmar 7900 carb question

[marsingbob]

I have a Dolmar 7900 that suddenly started running very rich at idle and power. Pulled the carb (Zama with C3M on the casting) and under the cover (bottom, I think, held on with 4 screws) there is a loose flat piece of metal about 1/8 by 5/8. I cannot see where it came from. Any help or suggestions?

 

[wde_1978]

I have a Dolmar 7900 that suddenly started running very rich at idle and power. Pulled the carb (Zama with C3M on the casting) and under the cover (bottom, I think, held on with 4 screws) there is a loose flat piece of metal about 1/8 by 5/8. I cannot see where it came from. Any help or suggestions?

Do You have any pictures of that metal piece?
It could help finding out what it is.

 

[rmh3481]

If this metal piece was inside the carb, under the cover with 4 screws, its the metering diaphragm and gasket that need to be replaced.

 

[ncfarmboy]

Sounds like the needle valve lever came out. See pg. 24 #213
Shep

 

[dugide]

sounds like the welch plug and would explain why its running rich.

 

[marsingbob]

Thanks for the help. In looking at the parts diagram and the carb more carefully it looks like the metal piece fits in a recess in the carb body and is the welch plug. Is it supposed to be staked in?? Can I epoxy it in?

 

[fordf150]

if it still has a slight convex shape to it you can try laying it back in the recess and taking a punch with a flat end on it and gently tapping on the center of the welch plug to flatten it out. when the plug flattens out it also expands in diameter. if it stays in place after doing that take clear finger nail polish and coat the edge of it to seal the plug to the carb body(very small amount around the edge). leave it dry overnight and reassemble for a trial run. If that doesnt work you will need to buy a new kit for the carb and it will include the welch plugs. do the exact same thing with the new welch plug that i just described for trying to reuse the old plug. you have to buy the complete kit to get the plugs....part number will begin with "RB". The "GND" kits only include gaskets and diaphragms.