going to try new prop
#1
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going to try new prop
Ok here I go, I have a 22 scarab, whimpy 7.4 with peanut heads and a friend lent me a prop to try out. its a 26 4 blade bravo 1. way too much I think but i am about to go try it for i have nothing better to do today. the boat came with a 25 mirage plus and ran 71 wide open stock no mods. one day someone needed that prop more then I and stole it and buggered the threads on my propshaft doing it, geez if your going to steal something at least be professional about it! anyway i had a 23 mirage and put that on and ran 65 then i changed exhuast to stainless, removed the 4600 rpm rev limiter got a bigger carb and put on a gill flame arrestor. I now go 69 but the engine hits 5000 maybee 5100 and runs out of air due to the heads/cam combo but i have lots of power right up untill she stops spinning. what do you guys think would get me the best for the engine right now? I dont want to put on the merlin heads that are laying in my garage right now and change the cam, I would rather use them for my next project and sell this one soon pretty much stock. It only has 150hrs on it so i dont want to tear it apart. any comments? I will be back soon to tell the results, i am predicting 65.
#2
GOT MERC?
Join Date: Aug 2001
Location: Boynton Beach FL
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Hey Loose,
It's pretty easy to figure out. First off I hope your speed # are coming from a gps not a water pressure speedo. GPS speedos are dead accurate. If you take 23 which is the pitch the prop is X the RPM which is 5100. You get 117,300 that is how many inches your boat moves foward per 5100 RPM. Not including the slip factor of your setup. I think you best choice in your case would be a lab finished 22 pitch Bravo I 4 blade. The out of the hole performance mid range and top end all will have a positive effect with this prop. Also you are in luck becaues I have a preowned one that I can ship to you in Daytona to try.
It's pretty easy to figure out. First off I hope your speed # are coming from a gps not a water pressure speedo. GPS speedos are dead accurate. If you take 23 which is the pitch the prop is X the RPM which is 5100. You get 117,300 that is how many inches your boat moves foward per 5100 RPM. Not including the slip factor of your setup. I think you best choice in your case would be a lab finished 22 pitch Bravo I 4 blade. The out of the hole performance mid range and top end all will have a positive effect with this prop. Also you are in luck becaues I have a preowned one that I can ship to you in Daytona to try.
#3
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Join Date: Feb 2002
Location: Honeoye, NY
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The guys at Merc will tell you that if the boat handling was ok with the Mirage then that will be the best prop for your top end. They can make a boat kinda hairy if you are close to "terminal hull velocity", but if you can drive it then get a Mirage, have it labed and go fast. --- Jer
#4
If your not having problems with handling or getting on plane than stick with the 3 blade mirage prop it will be 2 mph faster than a 4 blade. If you were spinning a 25 pitch before than I would try it again and have it lab finished. With the lab finish and the other things you have done you should gain agout 3 to 5 mph. GOOD LUCK
#5
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the engine blew its last breath. 70 mph 26 4 blade
i threw a spark plug into the batteries. and I mean into the batteries the end is stuck in the side with acid drippng all over nothing like idleing back to the ramp with people saying, is that boat suppose to sound that bad? i dont know how or why yet but the merlin heads are going on this week. girlfiend just doesnt understand yet, she was working
i threw a spark plug into the batteries. and I mean into the batteries the end is stuck in the side with acid drippng all over nothing like idleing back to the ramp with people saying, is that boat suppose to sound that bad? i dont know how or why yet but the merlin heads are going on this week. girlfiend just doesnt understand yet, she was working
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