19 pitch 16" prop wrong for my boat..need advice....

[Rodrunner]

Hey fellas i have a 18.5' fisher Deep V boat with a 150H optimax. The dealer put a 19pitch 16inch aluminum quicksilver prop on it. Well I'm only getting 5000rpm should be getting 5200-5700.Also top speed is a little under 40 and I should be getting at least 45 mph. Boat weighs 1500# dry. Please give me some advice on what size prop I should put on her thanks.. Jason

 

[Dhadley]

Re: 19 pitch 16" prop wrong for my boat..need advice....

First I'd take it back to the dealer since (it seems) you just either bought the boat or prop. But I wouldn't put a smaller prop on, I'd adjust the set up to gain rpm. Going to a smaller prop may only decrease efficiency. More rpm maybe but less efficient.

 

[Senderofan]

Re: 19 pitch 16" prop wrong for my boat..need advice....

Jason,

Wow...16" diameter prop....that sounds pretty big!! I can't give you direct advice...I'm more of a newbie. But, I have what sounds like a similar boat and motor combo. I have a Lund Fisherman 1800 ( 18.5 ft long ) it's a deep, wide fish and ski. My dry weight for the boat is 1470 lbs and I have a 150 hp Merc XR6 on it plus a 15 hp four stroke kicker.

Anyway, my boat came with a 14.25" 21 pitch Merc BlackMax prop. That prop would max @ 5400 rpm with just me in the boat...trimmed up for maximum gains. GPS read 46 to 46.5 mph. I've since gone to a 14.25" 19 pitch stainless (three Blade). Took the wife and two kids out for the maiden voyage using the new prop. I now spin to 5600-5700 rpm and GPS reads 50 to 50.5 mph. My maximum WOT rpm is rated 5200 to 5600 rpm. My motor seems to be quieter and more responsive where it currently lives. I don't think lugging these motors does them much good. I think you'll need to at leaast get down to a 14.25" diameter prop....but whether you need to go 19 or 21 pitch....I don't know. I corresponded with some Merc. 2.5 liter V6 outboard racers etc. on another site...they advised me to prop my engine such that it will get to the max recommended rpm at WOT...that these motors run best like that.

Good Luck,

Wayne

 

[Irv964]

Re: 19 pitch 16" prop wrong for my boat..need advice....

That does sound big, my 90 4 stroke Merc uses a 13.25 diameter.......Irv

 

[Rodrunner]

Re: 19 pitch 16" prop wrong for my boat..need advice....

I'd go to my dealer but he doesn't have a clue what he is talking about..He acts like he does but its obvoius that he doesn't..Here is an example. I say how do I break in this new merc optimax 150 (which was only a feeler question, i had already talked to mercery marine) he says ohhh just run it like you stole it.. WTF kind of answer is that..Anway pleasr give me some suggestions..I plan on calling mercury on mon. but would like top hear from some more of you..thanks a bunch

 

[Senderofan]

Re: 19 pitch 16" prop wrong for my boat..need advice....

I'd go to my dealer but he doesn't have a clue what he is talking about..He acts like he does but its obvoius that he doesn't..Here is an example. I say how do I break in this new merc optimax 150 (which was only a feeler question, i had already talked to mercery marine) he says ohhh just run it like you stole it.. WTF kind of answer is that..Anway pleasr give me some suggestions..I plan on calling mercury on mon. but would like top hear from some more of you..thanks a bunch

Well....A quick reference would be to use the "Prop Wizard" program....I think this site has that in the section where you buy new props. You input things like your boat, brand and size of motor (as well as year) what prop you currently have and what kind of performance numbers you are getting.

I suspect the program is going to tell you to get a 14.25 inch diameter prop and it will be something in the 19 and 21 pitch area. I've used the program umpteen times before I posted my question here....and it was fairly accurate.

Good luck.....It sucks having a dealer that doesn't help you sort things out....accurately.

Wayne

PS,

I just input information...used a Lund Tyee Gran Sport 1850 as the boat...and a 2005 150 Optimax ( Don't know the brand of boat or model you have...or the year of the motor). It gave several options of props...but they were 14.25 inch diameter and either 19 or 21 pitch.

 

[Rodrunner]

Re: 19 pitch 16" prop wrong for my boat..need advice....

thanks for the reply's..I'll try the prop selector..And yes it does suck not haveing a compitent boat dealer.The up side is that I'm slowly learning alot about my boat.

 

[Rodrunner]

Re: 19 pitch 16" prop wrong for my boat..need advice....

Still seeking any advice..