Onan B48M 18 HP - Bypass the fuel pump on the carburetor?

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  • / Onan B48M 18 HP - Bypass the fuel pump on the carburetor?
Looking at your pic's and description, there's several carb kits for that carberator (fuel pump as well-rectangular diaphram/gaskets) on Amazon.

I tried posting a link here, but it won't load.

Type in: iFJF K7523 Carburetor Repair Kit for Onan BG B43M B48M Marvel Schebler Model DD11 DD13 DD15 and they'll come up..
 

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  • / Onan B48M 18 HP - Bypass the fuel pump on the carburetor?

Arwing64

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  • / Onan B48M 18 HP - Bypass the fuel pump on the carburetor?
Thanks for everyone's help! I installed the fuel pump fixed with a carburetor gasket kit. Now it isn't leaking fuel and is pumping fuel like it should.

I did get the engine running but it is running way too rich. So I adjusted the fuel mixture screws on the carburetor, but it seems like it will only run when the choke is halfway open. It smokes like mad when the choke is closed, and sputters and pops when the choke is all the way open.
I've tried adjusting both the screws in many different ways but the engine doesn't seem to want to run smooth at all. I did replace the gaskets that are on the intake manifold that mate with the block and the carburetor. I thought there might have been a vacuum leak or something.

I looked down the mouth of the carburetor when its running and there is fuel splashing out of a port. I would have thought this was some sort of accelerator pump or something, but I'm not sure. I think this is normal but adjusting the valves will either make it run way too rich or way too lean. For some reason I can't get that perfect fuel mixture. It runs the best at part throttle. When I push the throttle from part throttle to full throttle, it puffs a ton of black smoke out the exhaust and can't run right. It sometimes surges as if it isn't getting enough fuel which I can't believe.

I'm stumped on this one. Normally tuning a carburetor is relatively simple but this one is certainly putting up a fight. I cleaned it one more time and reinstalled it and it does the same thing. Any suggestions?
 
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