idle to wide open throttle boat stalls at about 3000 rpm's

[moombachad]

need help
from idle to WOT my boat stalls at about 3000 rpm's for 1 to 2 seconds but recovers and runs fine, also runs fine
the rest of the time.

drained tank refueled with high octane non ethanol
replaced fuel filter
replaced water fuel filter
replaced TPS sensor

1998 MOOMBA OUTBACK
515 HOURS
INDMAR 350 GEN 1 PLUS EDL MPI ENGINE

[mmandley]

When your below 3k is it smooth and responsive?

When is the last time you changed plugs, wire, cap and rotor?


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[moombachad]

runs smooth and responsive other then when idling for long periods it
will surge sometimes.
haven't changed plugs, wires or cap and rotor

[mmandley]

I would start with those items

After that your prolly having issues on your carb secondary jets or plates

If you can have someone drive so you can see if the secondary butterflies are opening on your carb

You might be running super rich over 3k

Black or wet spark plugs will show that as well.

If butterflies are opening you might be having jet issues. At WOT you should see fuel spraying.


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[moombachad]

the 350 MPI is efi, but my next step was to change those items thanks

[zabooda]

First I learned Moomba used EFI in the 98s. I knew they offered both PCM which I have and the Indmar engines and that may be the reason. Besides what Mike mentioned, I would recommend running Seafoam through the fuel system.

[mmandley]

Sorry missed you had EFI lol


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[moombachad]

any body??????

need help
from idle to WOT my boat stalls at about 3000 rpm's for 1 to 2 seconds but recovers and runs fine, also runs fine
the rest of the time.

drained tank refueled with high octane non ethanol
replaced fuel filter
replaced water fuel filter
replaced TPS sensor
replaced spark plugs, cap and rotor

1998 MOOMBA OUTBACK
515 HOURS
INDMAR 350 GEN 1 PLUS EDL MPI ENGINE

[sivs1]

WOT on the three boats i have owned is higher than 3,000 rpm. What does it do at 4,000?

Other thought was fuel, but you're already using what I would recommend, have you burnt through a full tank of the good stuff yet? Maybe second full tank will be better?

[mikepo26]

I m thinking if the system uses a mass air flow sensor then as you accelerate it will not know the correct air flow and not provide spark and fuel properly

[trayson]

PLUG WIRES!!!!!

I had some issues with my MPI 340 CAT ETX and it ran 'better' after replacing the corroded cap/rotor. but it didn't solve my issues where it'd hesitate and die. but it didn't happen right away. I totally thought vapor lock, but that wasn't the case. If I looked at the wire that went to my coil, I could see the corrosion there. For me, replacing the plug wires was the last step and totally made my engine run like a boss.

Yeah, it's throwing parts and money as a guess of the problem, but you're probably due anyway. I was able to get the plug wires from Bakes with a forum discount and it was cheaper than ski dim.

[moombachad]

WOT on the three boats i have owned is higher than 3,000 rpm. What does it do at 4,000?

Other thought was fuel, but you're already using what I would recommend, have you burnt through a full tank of the good stuff yet? Maybe second full tank will be better?

it runs fine at 4000 rpm, if im going at a low speed and gun it will run through 3000 rpm's if
i gun it from a stand still it bogs/stalls every time at about 3000 rpm's for 1 to 3 seconds recovers
and run fine.

[moombachad]

plug wires look new but at this point i'll try anything thanks

[zabooda]

I had similar issues twice and replaced the electronic ignition each time. I thought it was a carb issue but it operated erratically. My mechanic knew right away.

[moombachad]

any body?
update
took out with engine cover off last week to adjust packing nut and it ran perfect, put it all back together and it's back
to stalling bogging for a second at 3500 rpms. What could be getting hot???


drained tank refueled with high octane non ethanol
replaced fuel filter
replaced water fuel filter
replaced TPS sensor
replaced map sensor
replaced spark plugs, cap and rotor and wires

took out with engine cover off last week to adjust packing nut and it ran perfect, put it all back together and it's back
to stalling bogging for a second at 3500 rpms. What could be getting hot???

1998 MOOMBA OUTBACK
515 HOURS
INDMAR 350 GEN 1 PLUS EDL MPI ENGINE

[mmandley]

When you say Engine cover explain this to me. Are you talking about the boat being a direct drive and you took the center hump cover off and it runs perfect?

Are you sure the engine isn't starving for Air?

[moombachad]

direct drive i had the engine cover off while changing parts, i left it off so i could get my axle packing nut
set while on the water. I run half a tank through it with zero problems put cover back on and now its bogging
again at 3500 rpms or so on hard start. 25857

[moombachad]

"HELP"
update.

changed ignition coil still stalls/boggs at about 3500 rpm
plenty of fuel pressure, thinking its fire but running out of parts to change.

[moombachad]

Update still bogging/stalling

do you have any insight or advice my mechanic is stumped???

it has zero engine codes.

He's thinking computer at this point.

been having this issue since i bought the boat last summer here's everything they have done.

stalling bogging for 1 to 3 seconds at about 3500 rpms on hard start and recovers (taking off fast or pulling somebody) it runs fine other then this.

drained tank refueled with high octane non ethanol, cleaned pick up filter"looked fine"
replaced check value on tank
replaced fuel filter
replaced water fuel filter seperator
replaced high pressure fuel pump
replaced low pressure fuel pump
replaced TPS sensor
replaced map sensor
replaced ignition coil
replaced spark plugs, cap and rotor and wires
replaced distributor today and set timing

1998 MOOMBA OUTBACK
515 HOURS
INDMAR 350 GEN 1 PLUS EDL MPI ENGINE

[kaneboats]

"took out with engine cover off last week to adjust packing nut and it ran perfect, put it all back together and it's back
to stalling bogging for a second at 3500 rpms."

Shot in the dark: I wonder what happens if you overtighten the jam nut and your shaft is out of alignment. Can there be a specific RPM where your shaft is binding? Won't hurt to check your alignment in any event.