26' cruiser powered by '89 5.7L Cobra prop help

[Durimar]

Hi everyone,
I've recently got a VIP 26' heavy cruiser/fishing boat and get around 3700 RPM at WOT against 4200-4500 factory spec. The prop that's on it now is 15-3/4" x 15". I'm thinking about switching to 15-1/2 x 13". What would you recommend, considering the engine is perfectly fine? Thanks!

 

[TilliamWe]

Re: 26' cruiser powered by '89 5.7L Cobra prop help

I don't see how the engine could be perfectly fine.

 

[Durimar]

Re: 26' cruiser powered by '89 5.7L Cobra prop help

So you think the problem is in the engine? Where do I start?

 

[Howard Sterndrive]

Re: 26' cruiser powered by '89 5.7L Cobra prop help

run through this list - fuel filters and cleaning the flame arrester would be first suspects.
Dirty hull, stuck advance weights in distributor also common

http://forums.iboats.com/showthread.php?t=295070

 

[steelespike]

Re: 26' cruiser powered by '89 5.7L Cobra prop help

I agree something other than a prop is going on.
Could be as simple as a plug wire off/shorted.
A compression check is a good idea you can check the condition of the plugs and their location at the same time.

 

[Durimar]

Re: 26' cruiser powered by '89 5.7L Cobra prop help

Thank you for your help. I will look in to it today and let you know how it went. Thank you again!