WOT rpm and top speed?

[wilson750]

I finally had a chance to take the boat out fishing.. The top speed seems to be very poor..At WOT its at 5200 rpm going 24mph..17p prop, 2 guys 13gal of fuel and some gear!! I dont know the weight of the boat,its not on the title..It is a very heavy 19' cc Its an North American.. Should the top speed be alittle better? I see posts that guys are going 38mph!!

 

[MikDee]

Re: WOT rpm and top speed?

And, how much horsepower are we talking about here? And, Or, what kind of power, outboard, I/O?

 

[wilson750]

Re: WOT rpm and top speed?

That would help!!! Merc 87 115hp

 

[MikDee]

Re: WOT rpm and top speed?

I'd say chances are the rubber hub in your prop is worn out, & spinning, like a slipping clutch, it's no longer grabbing the prop. A simple fix at a prop shop, or get a new prop.

One way to check is:
With the engine off in reverse gear, if you can grab the prop with gloves, and if it turns by hand clockwise on the shaft easily, the hub is shot.

 

[Chris1956]

Re: WOT rpm and top speed?

I agree with Mike. You should be seeing about 35MPH at that RPM, unless something is wrong.

 

[wilson750]

Re: WOT rpm and top speed?

Thanks guys..I have a new prop on the way because the prop that is on there looks like it went threw a war!! It appears it was bent and somone bent it back!!But I didnt think it would make it go that much slower!! The new prop will be here on thursday!! I will try to turn the prop also!!

Thanks

 

[wilson750]

Re: WOT rpm and top speed?

Just tried to turn the prop in reverse, It has alittle bit of play.. Id say about a inch before it will start to turn the motor over!! But I will put the new prop on thursday..

If one of the blades was bent alittle would it make it go that much slower?