Chamber

Well, It looks like everyone is concluding on the same fact. Overheating (Lack Of Water), or lean running condition. We are still waiting to find out what Merc is going to do before starting any work. Im going to have the ECU's, fuel injectors sent out and checked. After reassembly I will be sending both motors out for dyno so they can map out the ECU and make sure that fuel flow to each cylinder is correct. I no nothing about the ECU attached to the HP500EFI. We were at Carson Brummets shop on saturday, he had an EFI twin turbo charged motor on the dyno. There looked like there was alot of adjustment thru the entire rpm range with the ECU's running on the motor. Are the ECU's on the HP500EFI's the same were they can be reprogramed thru the entire range of rpm.

3DO

Sounds like were both in for a long winter!!!!! At least you block and heads are okay. Send me a PM and I will get you my office number and we can compare notes.

Jeff

I wonder if all these motors use the same electric fuel pump?

The fuel pump is mechanical in a HP500EFI. Thats one part that is actually still good on my motor. LOL.

Jeff

3DO, You laugh... but I've had two go bad over the last 3 yrs... It may not be good for much longer either! haha.

The feed pump is mechanical and the injection pump is electric. The mechanical pump drive (sea water pump drive) should be serviced each year when the impeller is changed. The drive cam uses gear lube that gets contaminated by fuel through slight leakage by pump. If not serviced properly the cam and pump arm will wear and not supply enough fuel to the injector pump.

Boatfixr,
What kind of gear lube is in the mech. fuel pump? The same lube as the outdrive?
MD

MD, use the mercury hp gearlube or better. I use Alisyn, Merc or Amsoil.

When the gear lube starts leaking it flows out the resivor hose attached to the pump right? Is that one way of knowing that you are due for a fuel pump. My port side (opposite motor) was starting to show signs of fluid running into that breather or overflow hose. Im not sure what the starboard motor (the bad side) fuel pump looks like. I do not that we will be replacing it upon repair. Do all the injectors generally get the same fuel pressure or if you start to lose pressure will certain cylinders be affected more then others?

3DO