volvo penta 4.3 bogging down at 3/4 throotle and above???

[slacka]

I have a 66 20 ft Bertram Bahia Mar with 1990 Volvo Penta 4.3 ( 431) with dp 290 boats always ran great wot it reaches 43 mph on GPS. a couple weeks ago I noticed at 4000rpm it seemed to be running a little boggy. If I try to give it wot it bogs right down ... If I ease off the throttle it runs great... Seems like the issue is proggresively getting worse... I have changed my in line fuel filter and fuel/ water filter... It has a Rochester 4barrell carb with electric fuel pump .. fwc. I am planning on a tune up . Plugs wires rotor cap and check timing any other suggestions on what it could be ??? Any help is appreciated thanks

 

[alldodge]

I have a 66 20 ft Bertram Bahia Mar with 1990 Volvo Pentagon 4.3 ( 431) with do 290 boats always ran great wot it reaches 43 mph on GPS a couple weeks ago I noticed at 4000rpm it seemed to be running a little boggy. If I try to give it wot it bogs right down ... If I ease off the throttle and runs great... Seems like the issue is proggresively getting worse... I have changed my in line fuel filter and veil water filter... It has a Rochester 4barrell carb with electric fuel pump .. fwc. I am planning on a tune up . Plugs wires rotor cap and check timing any other suggestions on what it could be ??? Any help is appreciated thanks

:welcome to iboats

I would suggest that maybe your fuel pump may be going out. Go get a vacuum fuel pump gauge and put it in line (tee fitting) between the fuel pump and the carb. Pressure should be 4-7 psi. Let us know what you find

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

 

[thedinz]

I have a 66 20 ft Bertram Bahia Mar with 1990 Volvo Penta 4.3 ( 431) with dp 290 boats always ran great wot it reaches 43 mph on GPS. a couple weeks ago I noticed at 4000rpm it seemed to be running a little boggy. If I try to give it wot it bogs right down ... If I ease off the throttle it runs great... Seems like the issue is proggresively getting worse... I have changed my in line fuel filter and fuel/ water filter... It has a Rochester 4barrell carb with electric fuel pump .. fwc. I am planning on a tune up . Plugs wires rotor cap and check timing any other suggestions on what it could be ??? Any help is appreciated thanks

Im going to follow this thread, i have the exact same issue but i have not checked anything of the things you have listed yet, due to time.

Though everyone i talk to says its fuel. Weather that means bad fuel, fuel filter. carb, fuel water separator? i dont know yet i will start checking 1 by 1 but its the same damn issue. Chugs along fine at half throttle or so, open it up and it goes fine for a sec then starts bogging out. Throttle down, no issues. I have the 3.0. 135.

 

[Pesimist]

I have a 66 20 ft Bertram Bahia Mar with 1990 Volvo Penta 4.3 ( 431) with dp 290 boats always ran great wot it reaches 43 mph on GPS. a couple weeks ago I noticed at 4000rpm it seemed to be running a little boggy. If I try to give it wot it bogs right down ... If I ease off the throttle it runs great... Seems like the issue is proggresively getting worse... I have changed my in line fuel filter and fuel/ water filter... It has a Rochester 4barrell carb with electric fuel pump .. fwc. I am planning on a tune up . Plugs wires rotor cap and check timing any other suggestions on what it could be ??? Any help is appreciated thanks

You've got the same setup as I have in my Chaparral except I have the engine driven fuel pump. It almost sounds like gummed up fuel in your carburetor, the secondary barrels should start feeding fuel about 4,000 RPM. Have you been using ethanol fuel? If so, it may have gummed up your secondary fuel jets.