Mercury 15hp prop question?

[bmoreboy52]

Quick question about a Mercury 15hp prop. I have a 16' smokercraft and recently put a Mercury 15hp motor on it with a 9 pitch prop on it. By myself I can do about 16-17 mph with rpm hitting 5200-5300 rpm. With another person with tackle and all I am running around 11-12 mph at 4800-5000 rpm. I was wondering if I get a 7-8 pitch prop of how much of a difference would this make? And I was wondering if Stainless or reg which would be better? thanks!

 

[steelespike]

Re: Mercury 15hp prop question?

Welcome,please describe the Smoker Craft.What year motor?2 stroke/4 stroke?In good tune,good prop?Have you tried different trim settings.
trimming in (prop closer to boat)will usually improve hole shot and easier to plane.But reduce top speed if trimmed in too far.Trimming out my improve speed but more difficult to plane.My experience the settings are not quite right allways seem to need a notch in between.
Anti vent plate(just above prop) Should be about even with the bottom of the boat.Not a lot of effect at your speeds but every little bit helps.
Weight distribution is very critical.Weight elimination is critical.
Use a 3 gallon tank move it to the mid section or to the bow.
Yes a 8" prop will improve your hole shot and increase rpm effect on speed
will be easierto tell with more details.

 

[hwsiii]

Re: Mercury 15hp prop question?

If you have the standard 15 HP Mercury the gear ratio is 2:1 check this please and by changing to an 8" Pitch prop from the 9" will raise your RPM to about 5,800 RPM from your present 5,300 RPM, and like steele said your hole shot will improve and you shouldn't lose any MPH, but when you have your friend with you you should be able to gi faster than you did before.

Prop Change

H

 

[bmoreboy52]

Re: Mercury 15hp prop question?

Ok I'm going to buy a 8 pitch stainless prop but on that motor how many tooth or whatever would that be? Would anyone know. Everyone that I talked to so far said that getting a 8pitch prop for that boat would def. help and when i'm by myself I just gotta watch my rpms so I don't rev it out. But when I buy the prop I just gotta make sure I get the right one for the teeth part or what not. Would anyone know how many it would be without me having to take the prop off? Thank you

 

[steelespike]

Re: Mercury 15hp prop question?

What year Merc?

 

[bmoreboy52]

Re: Mercury 15hp prop question?

Just bought a SS 8 pitch prop. Got it on my boat thursday took it out and by myself I picked up about one MPH and with two people picked up about 2-3 MPH. Its a very nice prop def. more of a hole shot I guess it will do what I need it to do.

Thanks,
Jeremy

 

[steelespike]

Re: Mercury 15hp prop question?

Great Its nice to see the pieces fall together for a success.
Do you have to watch the rpm when alone?