VP 4.3GS Fuel Delivery Problem?

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May 2, 2023
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2000 Reinell 200C, Volvo Penta 4.3GS.

I have been chasing a rough idle and bog at wide open for a few days. I was having intermittent problems with it cranking but no start. Now I can get it to start regularly. I rented a fuel pressure gauge set and hooked it up inline between the fuel pump and the carb. I took out a Mr. Gasket fuel pressure regulator to put this gauge in line, just to see what I was getting from the pump, and then would adjust the fuel pressure regulator from there. When I ran the engine, on muffs, I was getting about 4psi at idle, and it idles rough. I figured this pump should be pushing around 6-7psi. So I changed the fuel/water filter and ran it again. Now the gauge doesn't read any pressure. The idle hasn't changed, it is still rough. It runs smooth when you run it up around 1500rpms, but below that is rough.

For history, I just bought this boat, it sat for a couple of years with about 1/2 tank of fuel. I filled it topped it off with fresh fuel and have run it down to a half tank, and then filled it up again and ran it down to a half tank.

Would this even start and run without the fuel pump working properly? I am not sure where to go from here.
 

alldodge

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Putting good gas in bad gas just makes more bad gas. Doing 1/2 tank replacement a couple times will make the gas not so bad and enough should be fine

Pressure going from 4 psi to zero after replacing gas filter is weird, maybe the gauge. Spec list 4.9 to 8.5 psi at idle. Have you checked the antisiphon valve at the tank?

With rough idle and run good at higher rpm I would rebuild the carb. Use some thin wires to chase thru the idle passages
 

Scott Danforth

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Your carb needs to be pulled apart and gone thru
 

Bondo

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Ayuh,..... Welcome Aboard,.... Carbs like to be fed 4 to 6 psi, All the time,....
I agree with the above, fresh gas on bad gas makes more bad gas,.....
'n the carb needs to be pulled, 'n rebuilt,....
 
Joined
May 2, 2023
Messages
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Putting good gas in bad gas just makes more bad gas. Doing 1/2 tank replacement a couple times will make the gas not so bad and enough should be fine

Pressure going from 4 psi to zero after replacing gas filter is weird, maybe the gauge. Spec list 4.9 to 8.5 psi at idle. Have you checked the antisiphon valve at the tank?

With rough idle and run good at higher rpm I would rebuild the carb. Use some thin wires to chase thru the idle passages
The gas is still pretty dark yellow. I will drain the tank and clean it out. The gauge was for a fuel injected engine I'm pretty sure, it went up to 100+psi in 2psi increments. I put the filter on dry, didn't prefill it like you would an oil filter. The fuel line from the carb back to the pump was dry when I pulled the lines to install the pressure gauge. I might try to find a more suitable gauge in town. And I'll pull the carb and clean it.
 

Scott Danforth

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Would you buy the Holley kit or the NOS OEM Volvo kit? Volvo says it is unavailable, but there are a few folks on eBay with them still.
Volvo buys kits from Holley and marks them up. Go to Holley and look in the library and get the kit that matches your air horn number

However I personally would simply go to my bench where I have about 300 Holley gaskets. Most likely only needing a metering plate gasket, bowl gasket and accelerator pump gasket and check
 
Joined
May 2, 2023
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Volvo buys kits from Holley and marks them up. Go to Holley and look in the library and get the kit that matches your air horn number

However I personally would simply go to my bench where I have about 300 Holley gaskets. Most likely only needing a metering plate gasket, bowl gasket and accelerator pump gasket and check
I've got it partially pulled apart. The metering block is cracked. Looks like some one hit the center of it with a hammer. It's spider webbed out from around the center of it. That should be fun to find a new one. The front float was way too low. I'm surprised any fuel could get into the bowl.
 

Scott Danforth

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I've got it partially pulled apart. The metering block is cracked. Looks like some one hit the center of it with a hammer. It's spider webbed out from around the center of it. That should be fun to find a new one. The front float was way too low. I'm surprised any fuel could get into the bowl.
Read the air horn numbers

Go here and get part number of metering block.


Buy metering block from summit racing
 
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May 2, 2023
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Update on this now that it is fixed. Big time flooding and dumping so much fuel that it was mixing with the oil in the oil pan. The biggest problem was the primary metering block was plugged. A rebuild kit and running the parts through an ultrasonic cleaner got that part taken care of. My other problem with the carb was the secondary linkage was not allowing the secondary plates to close back up all the way so I always had a good 1/8"+ of transfer slot always exposed. A little bending of that linkage got the transfer slots back to where they should be when the throttle is pulled back to idle. Attached is the picture of the linkage that wasn't allowing the secondary plates to close up properly. I am assuming the PO put the fuel pressure regulator in line to try to compensate for the flooding. It was set at about 2psi. I have it set back to 6psi until my new fuel line comes in and I can get rid of that pressure regulator. I am not sure how much of a difference the new primary metering block made, but it idles like a dream now. Fires up by just touching the key. I will fine tune the carb when I have it at the dock.
 

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