stock prop pitch

[upted]

I have a 1969 starcraft islander aluminum 21 foot fishing boat with a 120hp mercruise outdrive #1, and I am wondering if anyone knows what pitch prop came on these boats as I got three with the boat and all are different. please help as I cannot afford to buy a bunch of new props to check rpms and what- not. all the props that I got with the boat are junk.

 

[QC]

Re: stock prop pitch

Well there is really no such thing as stock. In 1969 the 120 was a 1.98 ratio and would guess either a 15 or 17 inch pitch will put you where you need to be. Check in the Starcraft section too vvvvvvvv maybe one of them has a similar setup.

 

[CaptainHook]

Re: stock prop pitch

Even if the props you got with the boat are all junk the should have a part# on them if not pitch and diameter as well. Look for this info and it might be a good starting point!!!

 

[upted]

Re: stock prop pitch

thanks for the info The three props I have are 17, 19 and 21 so the 15-17 ssounds like a good start.

 

[CaptainHook]

Re: stock prop pitch

How bad are the props you have? If they are banged up maybe try running them and see what rpm your turning. It should get you close as long as they aren't missing a blade or something.

 

[upted]

Re: stock prop pitch

maybe I should try running one, do any of you folks know what the WOT should be on that 69 mercruise 120hp with the #1 outdrive???

 

[csadamsrep]

Re: stock prop pitch

maybe I should try running one, do any of you folks know what the WOT should be on that 69 mercruise 120hp with the #1 outdrive???

I believe my 120 i/o mercruiser, iron duke 4, has a WOT in the 4200-4400 rpm range, but I cannot say exactly as the boat is not with me now. My 120h.p engine is in a 19'6" Starcraft Holiday runabout, a 1995 model. I don't think these engines changed very much over the years, aside from breaker point ignition to electronic. Mine is electronic, but I suspect yours is breaker point style.

I do not know what prop I am running, but I am very pleased with it. It trolls down to 1.8mph at idle, around 650 rpm or so, and it runs about 40mph at around 3900 rpm. The extra few hundred rpm do not squeeze out any more speed with my setup. My Starcraft Holiday is a runabout open windshield style boat. Dry weight of the boat is only about 1600 lbs., but is has live well and a 9.9 Big Foot kicker. With fishing gear, expedition junk, full fuel, and 2 or 3 people I imagine I am up close to 2800lbs. or more when under way.

I imagine your boat is running an added 300 to 400 lbs. dry weight over mine.
I will ask my mechanic to check the prop on mine to see what it has, and will let you know what I find out. It may not be the best for your setup, but I will find out anyway.

Clay

Clay

 

[upted]

Re: stock prop pitch

thanks for the info clay