Motor Prop/Mounting height Question

[davides618]

I am running a 175 Suzuki on a 21 bay boat. The motor is mounted 2nd hole from top and running a 3 blade 16x23 prop. WOT trimmed out I turn 6300 rpm(Suzuki Max for this motor) with full tank of gas, all fishing gear and 2 large men in the boat. The cavitation plate is about an inch below the water. The dealer I bought the boat from said that is fine as long as I am turning my rpm. Another person told me I need to lift motor one hole and possibly a bigger prop. I would appreciate if anybody could give me some more insight before I bring the boat back to get serviced as to what really need to be done.

[LaAngler]

try running some numbers in a slip calc

what's your speed at WFO??

http://www.go-fast.com/Prop_Slip_Calculator.htm

[Dink]

You shouldn't be at rev limit with a loaded boat...............Your motor DOES need to be moved up, and you DO need a bigger prop.......Don't go crazy w/ the prop, just a few degree's at a time till you got it right......What's your speed at WOT??? Hows your holeshot??

[LaAngler]

how you know that dink? :cool:

how bout a hydraulic jackplate?

[Dink]

The last thing you want is to go too much on the prop.........Next thing you know, your going WAY too fast for the hull, getting air under it and flying in the air 6 or 7 ft because of a head wind............SCARY situation!!! Some boats aren't supposed to go 45 mph???? Just need one them spoilers like on them Jap cars???

[davides618]

Dealer says the motor height is right. They also claim that tachs are not accurate. They said that as long as my over rev does not kick in I'm alright. My tach shows 6300 rpm but they claim the over rev is at 6200 so I'm probably only turning 6000 to 6100 rpm. They also claim that I have the biggest prop they make for my motor. Talked to Suzuki and they were not much help either. Basically they only recited what is in the owners manual. They recommended I talk to another dealer in my area. So I called another dealer. As far as the cavitation plate he said it all depends on the boat that there is no set height that they are suppose to run at. As far as the prop he claims the tachs are accurate and said that the brand prop that I have on the engine is the one that gives them the most problem. He recommend that I go with the Suzuki prop (which the dealer I bought the boat from claims they dont carry those) because from their experience it is the best prop for that motor. He said they are a smaller diameter at 14 3/8 so I would defently need a larger pitch.

[Dink]

Your not looking to change Diam. of prop, just the pitch........is it stainless or aluminium?? If aluminum, throw it away............The cav. plate should be right at the bottom of hull(not the case w. tunnel hull). If it's lower than that, you will have alot more drag. W/ boat EMPTY(just you in it to drive and maybe 5 gallons of gas) you should be just under rev limit at WOT and trimed out...............That's how to test it.........That way when boat is full of gear and people, the rev's will be right where they're supposed to be at WOT.................that help??

[LittleRob]

Thanks alot for this I learned alot

[davides618]

Talked to Powertech and they said I could go up to a 16x24 prop but they don't make the 16 dia any bigger than a 23 right now. Said they plan to start making bigger than a 23 later this year. He said I could go down in dia and up in pitch to a 25 or 26 but I would loose my holeshot and gain about 2-3 mph top end and 1 mph at crusing speed. He said since I dont run WOT hadly at all (only reason I was running WOT right now was to make sure the prop was the right one) that I should be fine rigtht now untill they come out with a 16x24. Now I am waiting on NauticStar to call me back so I can talk to them about where they recommend the motor be mounted.

[Dink]

Bring it to a prop shop...........They will re-pitch it cheaper than you can buy a new one, and they are usually spot on!!! They'll give you better info than any dealer cause they don't have to worry bout factory specs or keeping anyone happy, with the exception of you of course..................Make sense???

[LittleRob]

Dink what prop shop would you recommend

[LaAngler]

these guys do good work, if IKE didn't take them out.....

http://www.coastalpropeller.com/default.htm

[Dink]

The Prop Shop in Lafayette.....

[LittleRob]

Thanks I live in Jennings. So Lafayette it is.