Prop change or jackplate adjustment

[ACAMACIAN]

I have been trying to set up my boat for it`s best performance. I am currently running a 25 pitch tempest prop on a 225hp efi merc on a 20.5 ft javelin fish and ski. The wot is approx 5600 rpms and 63 mph. I tried a 27pitch tempest ( but in bad shape ) and it was wot at 5000 rpms but 67 mph.
I keep thinking I could run the 27 pitch and raise the jackplate but I seem to lose speed when I raise it. I ran the slightly damaged 27pitch to see if I could spin it before I bought one. I am confused now on what I should be doing. I keep thinking if I raise the jackplate I will gain rpms, but I seem to loose.
I know this sounds like rambling but I don`t know in what direction I should be going.
Any suggestions would be appreciated.

ACAMACIAN

 

[Dhadley]

Re: Prop change or jackplate adjustment

The slip % with the 25 isn't great but not bad either. The slip and rpm with the 27 indicates that prop has been reworked and has more bite than a normal Tempest. Generally speaking the Tempest is a decent prop but your boat would benifit from a prop with more lift.

 

['96 Charger]

Re: Prop change or jackplate adjustment

I'll be watching this thread closely for my own benefit. Since slippage was mentioned what props are good about not slipping?

To the op when trimmed out are you throwing a big roostertail? And what year Javelin? Being an OMC boat you rarely see one with a non-OMC engine.

 

[ACAMACIAN]

Re: Prop change or jackplate adjustment

Thanks for the reponse. When you say more lift what do you mean? Should I be looking for a 4 blade? The 27 tempest did have work done to it and not good. I bought it for $60 just to see if I could spin it. Hard to find a prop that size around here to try out. What prop would you recommend?

ACAMACIAN

 

[ACAMACIAN]

Re: Prop change or jackplate adjustment

Hey Charger... my boat is a 1996 and it did have a 150hp when I bought it, but that was not enough, so I upgraded to the 225 merc.
When I ran the 27 tempest it through a bigger rooster tail then the 25. My brother was on shore and he noticed the difference. When it was mentioned the prop was worked that is true and I think one blade weakened when I ran it as it stopped performing as good when I first ran it.
I was told to get a tempest prop when I bought the motor, so I did, but hey I will take advice as I know there are people who know a lot more then me.

ACAMACIAN

 

['96 Charger]

Re: Prop change or jackplate adjustment

You won't hardly find a Mercury owner running something other than a Tempest since that's supposedly "the prop to have" for a Merc but who knows what people are thinkingJavelin is a really fast hull so set up right you should be able to hit 70 pretty easily even if it is a fish n ski. The people I know running the 225 Merc are all running a 25 pitch for the most part in 14.5" diameter.

 

[ACAMACIAN]

Re: Prop change or jackplate adjustment

You are right in saying that Charger, they all say get a tempest. And people tell me I should be getting 70mph but I can't get there. I am thinking now maybe I should get my prop checked over. My boat is a 409FS and is a heavy boat, so maybe 70 mph is out of reach, but I keep thinking if I get a 27 pitch set up right I may get there.

ACAMACIAN

 

['96 Charger]

Re: Prop change or jackplate adjustment

Being a deeper hull than a standard bass boat you're probably right on not hitting 70. 65 should be at least doable. My Charger is heavier than a lot of other rigs of the same hp rating but it ain't no thing. The rigs rated for a 200 that I won't take on in a race are Javelin, Stratos, Allison, Bullet, Gambler, Bumblebee, and I'm sure there's a few I'm forgetting. I have that deep keel in the front that stays stuck to the water to split the waves.

 

[ACAMACIAN]

Re: Prop change or jackplate adjustment

In saying I need a prop with better lift I am looking at a 23 pitch revolution 4 prop on ebay. Would this give me too much rpms? I am running a 25pith tempest now at 5600revs.

ACAMACIAN