High Fuel Pressure - 225 EFI

[nodima]

Been experiencing horrible fuel economy with my 1999 Mercury 225 EFI on my Mako 23 cuddy cabin. The boat had been around 1.7 MPG which is bad enough, but recently it has dropped down to more like 1.1 mpg. Boat was new to me last summer, so I don't have a lot of history with it.

Additionally, my WOT is only around 5200 with a light load. Prop is a brand new Mirage SS 15.5 x 17. Should be higher.

TOday, checked each cylinder for spark, and had good spark on all 6. This was at idle, at 2k and 3.5k rpms.

Back at the dock, we checked the fuel pressure with a loaner from Autozone. At idle, it read 46lbs, at ~2k RMP was 47lbs.

Signs are pointing to the VST area, should I be looking at the Fuel Pressure Regulator, or a filter in the VST?

Are there other tests to home in further?

 

[Faztbullet]

Check regulator as clogged filter on pump in VST will result in low pressure and areated fuel which will cause rough running.

 

[nodima]

Confused by your answer - my problem is high fuel pressure, not low fuel pressure.

 

[enginepower]

Well, not familiar with outboard EFI but I'm an auto mechanic by profession. If fuel pressure is too high, either the regulator is faulty or the return/dump line is restricted.

 

[jerryjerry05]

I had that same problem.98/225 EFI
The regulator was bad.
EVERYONE said the reg's don't EVER go bad. Even the Mercury guru's said that it was never a problem.WRONG
It made the motor use EXCESSIVE fuel.
Run CRAPPY, no power, etc.
Clean the vapor separator and make sure the hoses aren't soft and mushy.
Check the fuel pump pressure.
IF???? There has been any water in the fuel system the pump could be going.
At $500+ for a pump a bit of water can HURT ya.

 

[Faztbullet]

Signs are pointing to the VST area, should I be looking at the Fuel Pressure Regulator, or a filter in the VST?

Just saying its not a filter as pressure output would be lower if filter was clogged....

 

[nodima]

Just saying its not a filter as pressure output would be lower if filter was clogged....

Thanks for clarifying. That makes sense now.