Carb tuning - top carb not responding

mythx

Cadet
Joined
May 4, 2021
Messages
21
Hi, I performed a carb kit on my 1979 50hp 4cyl - S/N: 5336799

Afterward, when tuning the idle mixture, I noticed that when adjusting the idle mixture for the top carb, I get no response. The engine runs rough, and won't rev very high. I got a little improvement after adjusting the lower carb, but like I said, no change when adjusting the upper.

The carb kit didn't include the fuel pump diaphram, so that didn't get done. It's on order. Once I'm in there to do the fuel pump, what else should I take a look at? This is the carb with integrated fuel pump.

Any other troubleshooting I should be doing?

BTW, testing with lower unit submerged and in gear.

Thanks
 

mythx

Cadet
Joined
May 4, 2021
Messages
21
Just to followup.

Pulled the top carb, found the needle wasn't allowing the bowl to fill at all. It's a brand new needle, old one was still working, but it was discarded. I ended up bending the tab on the float. Issue resolved. Running on all 4 cylinders now.
 
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