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Low power and backfire

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Backyardmech

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I have a 2002 VIP 2102 with a volvo penta 5.0 gl. It back fires under load seems like a lean condition. What controls the fuel pump output?
 
the relay normally controls the pump's operation...there is no control that 'throttles its output'....
 
No regulator... Relay: Fuel Pump ON/ Pump OFF (@ no oil pressure, usually) You have a 2bbl carb, all fuel flow metering is done in the carb. Only control of fuel flow into the carb is the carb float valve, which again is ON/OFF depending on fuel level in the bowl,
 
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Hmm. I seem to have something different. The pump does not engage in run while engine is not running. It pumps while cranking. I hotwired the pump to remain on when key is turned to run and the pump overflowed the float and flooded.
 
No....Fuel pumps while cranking is the correct setup... engine starts, oil pressure builds, oil pressure sense switch closes, energizes the fuel pump via relay. Engine stops ( no oil) fuel pump stops.... While you hot wired the system and the pump kept running, the carb float apparently did not stop the fuel flow into the carb.... Possible incorrect fuel float level adjustment AND a defective/dirty needle seat.
 
Its a volvo penta filter replaced it last week. Disassembled carb and cleaned float bowl (was very clean inside). Sprayed carb cleaner thru jets. Also disconnected fuel line and activated fuel pump to check flow. Pumped about a gallon in 2 min. Pump rated at 25 gal per hr
 
I'm reading two issues....

1) you haven't said anything about the oil pressure controlled switch (for the fuel pump) being checked out...it appears to be failed based on your earlier posts....

2) Posts #5 & #7 contradict each other...the carb is flooding or it isn't....did you check the float while the carb was apart? did you verify the needle and seat assembly is functioning?
 
The float is copper or brass. Seems ok. Needle valve isnt stuck. Ill check the oil pressure switch first. Is it on the back of the intake near the distributor?
 
Wonder if this one ever got solved. Low power and backfiring, I would have checked timing first. Retarded timing would probably cause a backfire through the carb and blow the power valve(s). Typically would on a Holley anyway.
 
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