Power cutting out under load, but not neutral

[Tanner]

So the motor (MP 340 MPI) is cutting out at about 2500 RPM. Power just drops down then surges back up then back down. No alarms or anything. It only does it when it gear though. Runs perfect when in neutral. Is this bad fuel or fuel pump going out?

Other pertinent info... Fuel filter is relatively new (labor day). Cap and rotor are new as well.

[ChrisBarnes05-12-84]

I had a map sensor go out one time and caused the engine to struggle . Check the fuel pressure also

[NICKYPOO]

This seems to be very common at the moment. There are many things that could cause this but, more often than not it is something simple. Given that most people are just getting their boats on the water for the first time this year, I have to suggest a chunk of some old gas in the pick up of the fuel tank. It's the cheapest, simplest thing to check.

[zippCarlson]

I had similar issue last week on my 2009 rz2. I started with a can of seafoam and new gas, then moved to the inline filter, the FCC filter, cleaned the flame arrestor, cleaned the filter on the cooling water pickup and finally changed the plugs. I saw improvement at each step. Other than the FCC filter I didn't spend more than bout $25 to do all the other items ( excluding the gas itself at $5.29 a gallon ). Good luck!

[MRMoffat1]

Similiar. For me, the Service tech knocked the wire off one of the fuel pumps when replacing the impeller(cant rememember if it was the low or high pressure pump). Anyway, days later and an hour of on the water diagnosis with the computer monitor plugged into the engine ECM and he noticed no voltage at one of the fuel pumps. Then the ah ha......

Plugged the the wire back to the fuel pump, and been working ever since.

Maybe that's it.

[Tanner]

I'm getting 51 psi at the fuel rail, so it's not a rail pressure issue. But then again, I haven't checked the rail pressure under load, only on the hose. In addition, I pulled the fuel filter... to see if there was any water in the fuel. I let it sit a few hours and nothing! Zero water in the fuel. It also smelled perfect. So I'm kind of at a loss. Guess it's off to the dealer, well....after I check the rail pressure under load.

[majestic]

Batteries charged? When mine did that the house battery was depleted enough that the computer was seeing two different voltages and sending it into a limp mode.

[Tanner]

I dont get a limp mode. But ive rewired my system 2 years ago so that I don't experience the issue you saw.
Was worth a shot anyways

[ereed969]

Did you change the fuel water seperator and the in-line fuel filter? I had the same exact problem. I changed the water separator filter but not the inline fuel filter. Once I did that it was golden

[Nobody]

What kind of tool do you need to undo the hoses going into the in-line fuel filter? Looks like the old Ford a/c hose thingamajig dodad where you had to slide something inside to release internal spring pressure.

By the way, mine has one inlet and two outlets. I'm assuming the 3rd line is return if the filter is clogged??

[Dman54]

My 2008 rz4 starts great but struggles with acceleration, especially from 1-3k Rpms. Will back down power and then may surge to 3k+ RPMs. Tige mechanic says it’s the lower fuel pump that needs to be replaced.