one engine in 370 Alcan looses power after running short time

[Terry D Cook]

I bought a partially refurbished 1970 Alcan 370 2 new Volvo 4.3 liter engines and out drive had been installed. I installed new fuel tanks and fuel lines. both engines had about 70 hours on them.
When running both engines I can get boat up to 50 kph and one engine looses power and did quit running a couple of times. I can throttle back and get both engines running together again, but the one engine will loose power again when we pick up speed and wont even run properly at lower speeds.
I have changed the high and low pressure electric pumps and then the complete fuel unit. also changed fuel pressure relay. the fuel system includes the electric pumps and filter as well as compartment where fuel is supplied by low pressure pump and taken by high pressure pump.

​

 

[Scott Danforth]

what is the fuel pressure? most likely a boat side fuel system issue. however with new engines, you do get new engine support from VP

 

[QBhoy]

Hi. Without knowing more, I’d ask about your fuel supply system. Specifically around any restrictions it may have at the pick up or check valve. Are they running off the same tank ?
Edit. Just read you’d fitted two new tanks. Are the set ups man enough to supply the new engines ? What model of 4.3 are these ? Presuming they are gxi or newer having mentioned two fuel pumps ?

 

[QBhoy]

Is there a chance it’s not fuel related perhaps ? Is it definitely showing tell tale signs of fuel starvation? Like lean popping ?
Could this be ignition related as a result of voltage or Diz cap or similar

 

[Terry D Cook]

Is there a chance it’s not fuel related perhaps ? Is it definitely showing tell tale signs of fuel starvation? Like lean popping ?
Could this be ignition related as a result of voltage or Diz cap or similar

rough running and poping

 

[Terry D Cook]

Hi. Without knowing more, I’d ask about your fuel supply system. Specifically around any restrictions it may have at the pick up or check valve. Are they running off the same tank ?
Edit. Just read you’d fitted two new tanks. Are the set ups man enough to supply the new engines ? What model of 4.3 are these ? Presuming they are gxi or newer having mentioned two fuel pumps ?

two almost new engines with 70 hours, on new tanks and fuel lines, changed fuel system module consisting of high and low pressure pumps lines and filter as well as a holding container between low and high pressure pumps,