Prop and boat setup

[jrampey]

I have recently purchased a used boat - and have reviewed hundreds of posts on the forums here on iboats... thanks - I have learned alot. so much so that I have been tinkering with the setup of my boat. I have a 1984 18' Champion with a 150 Black Max. When I got it It would run 49 - 50 mph (GPS) at 5400 RPM with a 3 blade Turbo 14.25 X 24" prop. I want to use this boat to pull skiers as well as fishing so I bought a 13.75 X 23" 4 blade Trophy Plus. The motor was mounted high on the transom with the ventilation plate approx. 4" above the keel. After reviewing numerous posts here I decided to lower the motor... Lowest I can get it is still about 2" above keel, but wow! Took it to the lake Sunday to try out the changes... With the 3 blade 24" prop I was running 56mph @ 5000RPM WOT. Swapped to the Trophy plus 23" and still ran 56mph @ 5100RPM WOT. Looks like I should have gotten a 21"??? Interesting thing is I lost a little on the hole shot - the engine seems slower on acceleration - I'm thinking that the 4 blades are biting too hard and not letting the engine build revs. What should I do next - Anyone want to swap a 23" Trophy for a 21"... It has less than 2 hours on it?<br /><br />Thanks for any suggestions

 

[phatmanmike]

Re: Prop and boat setup

try having your prop "power ported"<br /><br />any prop shop will know what this is.<br /><br />i did it on my merc 115hp , i had a 3 blade 21p and after i had it ported , it took off like it had the hole shot of a 15 pitch prop, but did not affect the mid or top end of the 21p.<br /><br />best of both worlds

 

[sangerwaker]

Re: Prop and boat setup

Doesn't that Trophy Plus have the PVS system? The little black plastic plugs behind each blade? If so, just pop one out and retest. Those are for porting as Mike mentions. It will greatly improve holeshot if tuned correctly.

 

[Mettaree]

Re: Prop and boat setup

84: Have a 19" 3 blade Lazer II SS from a Merc 200hp if you think it would do you any good. I would consider trading. Its in perfect shape. You can get my email from profile if you so desire.

 

[LubeDude]

Re: Prop and boat setup

Originally posted by 84champion:<br />The motor was mounted high on the transom with the ventilation plate approx. 4" above the keel. After reviewing numerous posts here I decided to lower the motor... Lowest I can get it is still about 2" above keel,

First off, I wouldnt have lowered the engine, you should have tried the new prop where it was. You were over propped slightly to start with and probably needed a 23P which would have given you a better hole shot.<br /><br />If you raise the engine back up and install a set of smart tabs, you will have an awesome hole shot, be able to plane at about 10-15 MPH, and posably be closer to 60 MPH with the four blade you have. Some one put the engine where it was for a reason.

 

[jrampey]

Re: Prop and boat setup

The Trophy Prop has the PVS system - the plugs currently are approx 1/4" I will try popping one out tomorrow. I have thought about the smart Tabs... may do it yet - but I thought I should get the RPM's at WOT right first.<br /><br />JKW - we may talk!

 

[Mettaree]

Re: Prop and boat setup

84: I was wrong about profile - if you decide to contact me use: w_jamesk@bellsouth.net or contact me at: jkw1939@gmail.com

 

[LubeDude]

Re: Prop and boat setup

Originally posted by 84champion:<br /> I have thought about the smart Tabs... may do it yet - but I thought I should get the RPM's at WOT right first.<br /><br />JKW - we may talk!

When I put the tabs on the boat in my avitar, I had to reprop to a larger prop, so if you are going to get the tabs, (Which I highly recomend), do them first.