Low Fuel Pressure 2005 Mercruiser 4.3L MPI

[Tristan1985]

Hang on, just checked your serial number and it seems that you do not have a LP pump, sorry for the mistake. Most of these do so I blindly assumed you have one. I stand corrected. But still do the clear hose test on the return from the HP pump and the clear hose test from the tank to check for air. Also to check for leaks you could pressurize the entire system and do a sniff test. Also, if your motor got destroyed earlier due to a lean run I would consider adding a boost pump, the type from newer serial numbers.

Hi, thanks I will try the clear hose test.
When disconnecting the return line and doing the clear hose test there, do I need to put a closed hose on the filter connection where the hose was?

 

[alldodge]

But still do the clear hose test on the return from the HP pump and the clear hose test from the tank to check for air.

Doing this is not going to prove anything

 

[vroom ZOOM]

Hi, thanks I will try the clear hose test.
When disconnecting the return line and doing the clear hose test there, do I need to put a closed hose on the filter connection where the hose was?

Yes. I think you can also use a 3/8 NPT plug. let the pump run a few cycles before looking for air in order for the air that got in while messing with it to get purged. also MAKE SURE to check for water in fuel.