Fuel pump issue

[kd4pbs]

Agreed… in an automotive system. I am sure they have been used, but every marine EFI I have had experience with uses a single connection supply from the tank and that is all. I figure they don’t want yet another line to possibly cause hazards or since the tank might be well insulated and buried in a boat versus an automotive system, it might not get adequate cooling and potentially build heat to dangerous levels, especially as the tank gets more empty.
Now that we know the OP has a fuel injected engine, I would recommend ensuring the cooling passages are clear and that cooling water is circulating as designed.

Disregard. I re read his 1st post and it is a 4bbl carb. I guess Mercruiser used an electric pump on those? I would have assumed it would have been a solenoid style pump that doesn’t heat up significantly if so.

 

[ste80]

It is a time & use related problem.......... Your replacement might be a unit made same date as yours. Bad quality units. Is your engine running a NEWER AND HOTTER thermostat ? Check pump temp with a a laser dot thermometer.

Hi i did already and it was between 65 and 70
I want to use also a new laser next time anyway

 

[ste80]

Is this fuel injected? I've never seen a fuel injected marine engine fuel pump that did not circulate raw water through it to cool it.

It is not ijections, it is 4 bar carbs so low pressure pump.
My old efi had high presure pump and heat exchange on pump ( copper cooler)

Anyway i thin i solved the problem.

I moved the pump out of the motor (i put on the wood near the motor)
Today i run the motor for 40 miles and everithing was find
During running i check pump with laser and in that position it was workimg at 35 deg
Where it was before near the motor it was 70

This seems to be the isue

 

[ste80]

Is this fuel injected? I've never seen a fuel injected marine engine fuel pump that did not circulate raw water through it to cool it.

It is not ijections, it is 4 bar carbs so low pressure pump.
My old efi had high presure pump and heat exchange on pump ( copper cooler)

Anyway i thin i solved the problem.

I moved the pump out of the motor (i put on the wood near the motor)
Today i run the motor for 40 miles and everithing was find
During running i check pump with laser and in that position it was workimg at 35 deg
Where it was before near the motor it was 70

This seems to be the isue