prop size and...

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   I have a 20' 1971 Freeport.  I think it has the 302, I'm still trying to figure out what has been done to it by prior owners.  It has a federal 13x14, it won't get on plane unless only 1-2 people and takes almost a minute!  TOO much prop?  Also after further review I see that it has only about 1/4" clearance to the hull.  There has been some work there before so I guess it is too close, according to other threads.  What to do.  Also it slows down greatly when you make a turn, not even a sharp one.  Is this a deep-vee thing or because too much prop.  Wish I could tell you RPMs running but they don't get very high.  Didn't store it with Sta-bil and carb was funny so I cleaned it and now runs OK, no back fire, but still won't go good.  At least now it barely starts to open the secondaries, Holly 600.

There's more..  I have not set the timing according to specs yet but when WOT and 1800rpm, a guess, it likes a little more advance than at 2500, which is as fast as it turns right now.  I set it at best advance to get max speed at 2500 rpm and it takes a long time to get there.  I have it somewhere between now.  Seems to like a little more advance at lower rpm.  I have no idea about the points and have never tinkered with mech adv timing.

Give me a engine with computer and I know what I am doing but this is foreign to me.

Help

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Paul Dee Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Post Options Post Reply Quote Paul Dee Thanks(0) Quote Reply Topic: prop size and... Posted: August-08-2005 at 6:42pm
	I have a 20' 1971 Freeport. I think it has the 302, I'm still trying to figure out what has been done to it by prior owners. It has a federal 13x14, it won't get on plane unless only 1-2 people and takes almost a minute! TOO much prop? Also after further review I see that it has only about 1/4" clearance to the hull. There has been some work there before so I guess it is too close, according to other threads. What to do. Also it slows down greatly when you make a turn, not even a sharp one. Is this a deep-vee thing or because too much prop. Wish I could tell you RPMs running but they don't get very high. Didn't store it with Sta-bil and carb was funny so I cleaned it and now runs OK, no back fire, but still won't go good. At least now it barely starts to open the secondaries, Holly 600. There's more.. I have not set the timing according to specs yet but when WOT and 1800rpm, a guess, it likes a little more advance than at 2500, which is as fast as it turns right now. I set it at best advance to get max speed at 2500 rpm and it takes a long time to get there. I have it somewhere between now. Seems to like a little more advance at lower rpm. I have no idea about the points and have never tinkered with mech adv timing. Give me a engine with computer and I know what I am doing but this is foreign to me. Help

mackwrench Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February-25-2005 Location: Gone Status: Offline Points: 190	Post Options Post Reply Quote mackwrench Report Post Thanks(0) Quote Reply Posted: August-08-2005 at 7:27pm
	I would think it'll pull that size wheel, I have a older Mustang, 302 engine w/that same size wheel & pulls like a train! Yours may have had a 12X12 when new though. You really should check the points... or change it to electronic. Either way sounds like ingition issues.
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Jerry Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Post Options Post Reply Quote Jerry Thanks(0) Quote Reply Posted: August-08-2005 at 10:34pm
	There is no way my 302 would pull a 13x14 prop on a twenty foot freeport. My mustang is 17' and the stock prop is a 12x14 which maxs the rpm's at 4400. I dont know what other problems you may have but i certainly think you have to much prop for that combination. i'd call the factory and ask what size prop the boat originally came with. good luck.

Duck Soup Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Post Options Post Reply Quote Duck Soup Thanks(0) Quote Reply Posted: August-16-2005 at 1:48am
	I'd be willing to bet if your motor is a 302 it was a replacement for the original. Your pitch is to High but it sounds like you might have some other HP issues. Your engine should be able to hit 4200 rpm or you will damage it (overloading). One big issue you have is your prop is to close to the hull. You need at least 15% of the diameter of the prop clearance from the hull, that figure might be higher but that's what I remember. Your situation is cheating the prop of it's performance. I suspect when they put the present engine in they needed a longer shaft. It sounds like they used the old shaft and prop on the lesser HP engine. With a longer shaft your prop will be farther away from the hull and able to perform better. I would see if you can borrow a 12x13 and see what that does to start. Good Luck

GottaSki Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3335	Post Options Post Reply Quote GottaSki Report Post Thanks(0) Quote Reply Posted: August-17-2005 at 1:31pm
	I concur, too much prop for that big a boat and short-stroke engine.
	"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole

mackwrench Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February-25-2005 Location: Gone Status: Offline Points: 190	Post Options Post Reply Quote mackwrench Report Post Thanks(0) Quote Reply Posted: August-17-2005 at 7:06pm
	My 4' shorter, several hundred poundslighter, mildly modifed 302 powered CC Mustang does in fact pull that size wheel, But I agree after re-reading your orginal post that you would be beter off with a smaller prop! Mine has about 2" betewwn hull and wheel, so shaft length must be different too. You can check e-bay, I have bought several used props there, just be careful of any that have been "repaired"
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rutancanard Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: August-18-2004 Location: United States Status: Offline Points: 7	Post Options Post Reply Quote rutancanard Report Post Thanks(0) Quote Reply Posted: January-02-2006 at 5:36pm
	I know it's been a while but... My wife didn't like the idea of a boat so one of them had to go. I still have the boat, doesn't bitch at me. I got a 13x13 prop and it screamed. Then I thought about the post someone had about the foam being water logged. I weighed it and guessing at the trailer weight we figured the boat is about 2400lbs!!!!!!! So I know what I'm going to doing, floor and foam, when divorce is done.
	'71 Freeport

prop size and...

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