Engine cuts out at high speed

[RedVegas91]

I have a 91 vegas with (I believe) a Merc 2.4 built to 2.5 specs. I used to be able to do around 90. The motor would lose all power at about 5700 rpm. If I would back off of the gas and push it back down, it would be fine. The engine never turned off. I burned out a voltage regulator a year ago and replaced it. Now the motor cuts out at 5500 rpm and I can't get the boat above 72. It seems everyone I talk to tells me something different. I have been told to replace the brain box, trigger, power packs and I believe the Stator.

Any ideas? I'm thinking this is an electrical problem, but it could be fuel related.

Also, If I put my 19" High 5 prop on I can turn 6000 rpm with no problem. The cowl has louvers, so it should be getting enough air.

Thanks, Bill

[RedVegas91]

Does anyone have any ideas about this?

[us1]

Look into fuel presure and GPH. Sounds like it might be a blocked fuel filter or bad fuel pump.

[RedVegas91]

Thank you for your reply. Pardon my ignorance, but what is GPH?

[us1]

Volume, Gallons Per Hour

[HighVelocity]

It sounds like you have made a case for a load problem. With minimum load you can go right up to 6 grand. Now,, with a load(more pitch) you can't.

Has the advance changed on the timing? A retarded advance or no advance will have that effect with a load.
A weak or intermitin spark at high RPM will do that too.


If your thinkin fuel, do your plugs look burned? and has your engine temp been good? Maybe you could have someone pump the ball at that speed and see if she surges. It would have to be a flat day of coarse.

my though process,
HV