Prop Question

[Raymond]

Will a prop off of a 25 hp motor fit a 40 hp? I am buying a 40 merc fri and would like to try out my bosses prop that is a 13 after running the 11 I have. Where's the motorheads with all the knowledge?

[simplepeddler]

in all likelyhood yes..(same motor manufacturer)......but that 40 may turn it too many RPM's.
the motor website would likely have that.

[wtretrievers]

Get with Montauk17, he fools with props.

[Raymond]

ran a 11 on my last one but it came with a 13 that did not give me any hole shot on my 18x42 tunnel. Worried the 11 is going to be too small for the merc and it actually a 50 but same block. I am trying to get the most speed and hole shot possible so might have to speriment a little. Thanks for your reply.

[rosska]

Raymond you need to get a tiny tach for the motor. It is very easy to put on an will tell you how many rpms you are turning. Once you install the tiny tach you need to raise or lower the motor so the cavitation plate is just below the water when you are running. Load the boat just as you are going fishing and take it down to the old ice plant at the end of ryan st and run it with a gps. Wide open you should not turn any more than the motors recommend max rpm. If you do you exceed the max rpm you need to go to a bigger prop if your rpms are low you need to try a smaller prop. Once you get the prop figured out adjust the motor up and down and try different pin adjustments until you see a decrease in speed then back up to the previous setting. Once you do all of this your rig will be setup for peak performance and you will not be able to see any gains unless you do motor mods which could allow you to run a bigger prop and do it all over again. Hope this helps

[B-Stealth]

I think..... Sulphite runs a 13 on his 40 Merc 60 Carbs and that boat had a wicked wholeshot.

I beleive it could turn more prop and have a better top end.

[Raymond]

Marsh I am picking up is soft and shallow so hole shot is going to be a deal breaker. Also will be hauling a load atleast 7 miles so speed needs to be there.
Ross, if you want to come over and help I will buy the beer. Hope all of the mud came out of your boat.

[Marshrat]

More than likely the hub will be smaller on the 25 prop. If not the pitch and diameter will not be right.


Warren