View Full Version : Engine Power Loss Bogging Down

04-26-2011, 06:31 AM
Moomba Mobius V 2000
Indmar 350hp MPFI 5.7L

Had my boat out all weekend and have found i now have an inconsistent power problem.
Boat has been in storage for 7 months, with stabilizer added to a full tank of gas.

Ran her last weekend for 2 days, no problem, started first time, pulled no problem.
Then, this weekend, after 2 days, she started bogging down at 1600rpm... give it more throttle.....just the same, bogging down, white smoke, no power, lots of noise.

Wait 2-3 mins, then off we go again, great......5-10 mins later, bogging down again.
Problem happens with or without Wakeboard-Pro on.

I have added about 80 litres of fuel since initially running, so i am thinking its not water in the fuel.

I changed the fuel water seperator/filter before the first run this year.

Then, i notice there is a kink in the fuel line before the block, AND what looks like an in-line filter, which i have never changed (in 4 years).

I guess my first check is change that filter.......

What about dirt in the carb?

The 1600rpm is wierd......is it at that rev the engine suddenly requests more fuel?

Any help appreciated.

04-26-2011, 10:22 AM
Definitely start with that filter. But also inspect fuel lines. I have seen old lines that would "suck closed" when a load is put on them because they are soft. A cheap piece of line solved the problem.

04-26-2011, 11:21 AM
I'd start with that fuel filter but you might as well also check the plugs, wire, cap and rotor if they are original too.

04-28-2011, 10:54 AM
Indmar #5560003

Cross references exactly to a Mallory Pt # 9-37824R, and a AC Delco GF481 filter.

Old filter full of crap, no wonder it was bogging down.

Trials tomorrow.

Bring on the long weekend!!!

Ian Brantford
04-29-2011, 11:30 AM
That's good news! The same thing happened to me last year.

Another thing that happened was that the mechanic did not check the V-drive oil (SAE 30) and the sensor warned about it in my first 5 minutes of driving. The engine appeared to be in a limp mode. on the way back.

04-29-2011, 02:00 PM
MPFI does not have a carb

05-09-2011, 05:00 AM
quote "MPFI does not have a carb" unquote


Then how come i take the flame arrestor off and look down into a carb???

My engine and docs all state MPFI, and Indmar confim.

Anyway, going back to the original power loss bogging down problem....

It was not the fuel filter....

There was crap (reeds, dirt, mud, small stones, etc) blocking the heat exchanger inlet on the raw water cooling system.(i dont have a filter)

It was completely blocked.

So, what must have been happenning, was that the engine was overheating and the fuel was burning or evalorating before ignition.

Cleaned it all out, and no problem since.

I think i will get a filter now.

05-09-2011, 09:33 AM
MPFI stands for multi port fuel injection. no carb. it has a throttle body you can look down inside but not a carb

05-10-2011, 04:44 PM
I stand corrected.........