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PROP CHOICE need help

I could be out to lunch on your gear ratio. It could be an Alpha with 1.32 gears. You may want to check and get back to us.
 
Hotrodboat said:
I checked the gear ratio on the outdrive. It says 1.50R
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I would say that you are really lugging that motor with those big props. 25p with that drive is way too big. Slip is 15%, The 27p is 18%. Should be 11-12% with that boat. Play with this calculator to run the numbers. http://www.go-fast.com/Prop_Slip_Calculator.htm
With 300hp and 1.5 drive you should probably be around a 21p or less. See if you can find one to try.
 
So I got a little history on the boat. It used to have a 700 hp blower motor in it that turned these larger props. I guess when the previous owner switched engines he didn't switch to a smaller prop.
 
Anyone tried the solas titan 4 blade prop?? I'm looking at maybe getting one in a 21p or 22p?? What do you think? Good brand? They are cheaper than others price wise but what about quality?
 
I would think the 21p 3 blade is the right prop to get those rpm's up. I've got a pair of stern drivers and I can tell you that the Bravo 1 4 blades or the mirage 3 blades are 10 times the prop. Way better quality and better results as well.
 
diesel30 said:
I would think the 21p 3 blade is the right prop to get those rpm's up. I've got a pair of stern drivers and I can tell you that the Bravo 1 4 blades or the mirage 3 blades are 10 times the prop. Way better quality and better results as well.
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Yup, don't mess around, find a used 21 Mirage and away you go. These props were designed for this type of set up. Lots of them around, all the Bajas use them. You will pay more for Bravo one.
 
Just to give an update. I talked to a guy at Checkmate today. He said the boat came with a 25p or 23p mirage 3 blade originally and I shouldn't have a problem turning the 25p that's on it now. Sometime this week I'm gonna put it in the water and see if the vacuum secondarys are opening all the way or if the choke is stuck closed. Has a marine 4 barrel quadrajet on it now. After talking with Checkmate I don't think the prop is the problem.
 
What happened to the story about the 25p being from a 700 HP blower motor?

I suppose a 310 hp 454 could turn a 25. Keep us posted.
 
Ok update here. Got the boat in the water. Reved it to wop. Secondary flap is only opening a quarter of the way. It's a 750 crm marine quadrajet. I'm looking into what I need to fix it. Any thoughts would be appreciated.
 
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