Can anyone explain this???

[scott8058]

Boat: 95 bayliner 2050 ss, 5.0 swapped out for a 355, 5.0 alpha one out drive

Ok so here was my problem....the boat would run fine up to 4000 rpms with a 15.5 x 19p ss 3 blade prop, if you gave it anymore throttle after that (it had plenty left) and i mean any more at all it would bog down for a sec then rip wide open and run 5200 or higher (to high i know). There was no in between you were either doing 35 mph or over 50. I thought it was a carb issue with the other two barrels opening early and just figured it needed rebuilt but when i switched props yest and ran a 14.25 x 21p alum, it ran right thru the whole rpm range beautifully. Any ideas why the ss prop was causing the engine to do that?

Thanks!

 

[steelespike]

Re: Can anyone explain this???

Just guessing If the secondary is on a vacuum The ss presents just the right load that the secondary pops open.
I assume your not advancing the throttle any farther once this happens.,

 

[scott8058]

Re: Can anyone explain this???

Once it would rip open i could pull it back and run in the normal range, so no it never ran that high for more than a couple secs. Im really glad i tried the spare alum one i had before i tore into the engine. Does the weight of the ss prop have anything to do with it, since its prob twice as heavy?

 

[Tail_Gunner]

Re: Can anyone explain this???

You need to go up to the I/O section your carb is miscalibrated...sounds like a accelorator pump jet thing

 

[scott8058]

Re: Can anyone explain this???

Why doesn't it happen with the other prop then?