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dspowers · 05-09-2011, 06:56 PM

I replaced my fuel pump on generator, after adjusting the fuel mixture with the shut-down control removed the gas flow seems to be correct until I put the air filter on, the carb seems not to breath and backfires with black smoke!! what am I doing wrong?

W4RLR · 05-10-2011, 12:05 AM

Quote:

Originally Posted by dspowers

I replaced my fuel pump on generator, after adjusting the fuel mixture with the shut-down control removed the gas flow seems to be correct until I put the air filter on, the carb seems not to breath and backfires with black smoke!! what am I doing wrong?

When the air filter gets put on, it restricts the air flow to the point that the generator runs rich. That explains the backfire and poor performance.

Can you adjust with the air filter ON the carb?

JimM68 · 05-10-2011, 05:45 AM

While I agree with the poster above, I'd also find it real unusual that a proper air filter would make such a difference?

Is there something wrong inside the air filter, a restriction of some sort?
Is it interfering with some linkage when you put it on, perhaps closing a choke or something?

dspowers · 05-10-2011, 09:09 PM

The generator is running very rich I adjusted idle fuel mixture screw 1-1/4 turns out and engine does not start, unless I turn idle fuel screw back down, but it seems that the engine is running hard, it stays started but there is gas shooting from carb. When I put the shut-down solenoid back it does not start at all. After it runs for about 3-5 min seems like it less gas shooting from carb, my fear is the gas shooting from carb. What should I do to fix this problem myself $$$$

TQ60 · 05-10-2011, 09:18 PM

Float is not seating and allowing rich condition.

LVJ58 · 05-10-2011, 10:22 PM

sounds like the float level may be off and doesn't close the needle valve completely when fuel bowl is full and excess fuel getting sucked into the venturi resulting in rich mixture.

dspowers · 05-11-2011, 01:04 AM

How do I adjust the float level, I have the owners manual but nothing about the float only the carb,choke and governor. Which of these controls the float?

GreaseMonkey · 05-11-2011, 05:53 AM

Quote:

Originally Posted by dspowers

How do I adjust the float level, I have the owners manual but nothing about the float only the carb,choke and governor. Which of these controls the float?

As stated the needle may not seating.

Does fuel leak or drip from the carb when not running? It's a clear indication of the issue at hand.

Depending on clearances you may have to remove the carb.
Remove the fuel bowl followed by the float then needle and inspect for any gummed up gas or debris on the needle and where it seals up against in the carburetor.

With it not sealing properly the bowl overfills with fuel and gets sucked through the overflow tube and into the carb causing your rich mixture.

bigskymt · 05-11-2011, 01:58 PM

With the generator running tap on the side of the carb. with a small hammer or screwdriver handle, this should free up the float. Onans were notorious for float/needle&seat problems. Either dirt or a groove worn into the needle will prevent it from seating properly and cause flooding. I've seen some needles with a neoprene base that wears on the seat and refuses to seal properly. Not sure if this was Onan or an aftermarket part. They also had a problem with their float: some were porous and would actually absorb gas and sink thus opening the seat. Others were brass and would leak around the soldered union and also sink.

ga traveler · 05-11-2011, 03:24 PM

Did you buy the fuel pump from kohler? It sounds like you have a fuel pump that is putting out way too much pressure. Just because it is the same type and make pump, Does not mean the pressure is right.