Completely confused about 3.0 alpha one prop replacements...

[HeloMech]

ok, so I just picked up this '87 freedom 17' openbow with mercruiser 3.0 and alpha one outdrive. The aluminum prop looks like the previous owner drove it through a rock quarry or something. I pulled the prop and it says J15x17P, which I'm assuming to mean 15" x 17pitch. Though everything I can find online shows a 15 pitch prop for this setup.

Are there suggestions as to what prop to put on this thing? I thought about having this prop repaired, but I'm wondering if it's even the right prop for the boat. Also, what are the limitations of damage that can be repaired? The edges are dented and even have a couple of tears.

I've used the search function and read quite alot about props, just haven't found what I need as of yet.

Thanks in advance for any help you guys can offer....

also, this is my first boat. Replaced the steering system, fixed the electrical that drives the hydraulic trim motor and got the engine running.

 

[bulldogboogers]

Re: Completely confused about 3.0 alpha one prop replacements...

man it's a small world... i went up to silverwood lake yesterday... and got to close to shore & hit a big rock... it took out a big one inch piece out of my propeller..... i have been looking for one all day... i also have a mercury mercruiser alpha 3.0 135 h/p and my boat is a 2004 bayliner..... just made me sick when i did it !! o-well live & learn !..... i also can't find a ser # for the prop at all ... and i even have the manual for the boat !... so if you find the prop please e-mail with the info.... at bulldogboogers@att.net

thanks again scott from corona hills, ca

 

[Silvertip]

Re: Completely confused about 3.0 alpha one prop replacements...

Bulldogboogers -- just because someone has the same engine and outdrive as you, does not mean the prop must be the same for your boat. A heavier boat than yours will use a prop with less pitch than yours so your engine would likely over rev if you used the same prop. You need to get us some wide open throttle RPM and speed info. Tough to do accurately with a chewed up prop but the best we can do is quess. You are advised to take your prop to a prop shop. They can use a pitch gauge to tell you what pitch it is. You can measure the diameter as I explained in your other post.

HeloMech -- read the sticky at the top of this forum titled READ THIS FIRST. It explains what's needed to fine tune a prop setup.

 

[HeloMech]

Re: Completely confused about 3.0 alpha one prop replacements...

Silvertip: I read the READ ME sticky and I thought I was putting out what info I have available. It's a 17' open bow with mercruiser 3.0 and alpha one outdrive. From what I gather, the boat is about 1800 pounds. I have no idea what the wot rpm's are as I've not put this boat in the water. I don't see a point when I look at this hammered up prop. That's why I'm trying to get the information on which prop is supposed to be on there so I can get it in the water and go from there.

I have no clue if this 4cylinder would pull a skier out of the water so I don't know if it's worth mentioning that it's to be used for skiing or just fishing and touring local lakes. Sure, i'd like to be able to pull a skier out of the water on a single ski, or a tube, etc. I don't really care about top speed since, well, it's a 4cylinder and I'm not out to race anyone. Just trying to get an idea if this 15x17 was there from the dealer or something the PO put on there. If it's stock, then I'd ASSume I could go to a 15x15 or something like that for the lower end. This boat will rarely, if ever, see a long wot run. It's old and no point in beating it up.

I'm heading over to WestMarine at lunch to see what they have to say. I brought the J15x17p prop with me so they can take a look at that as well.

 

[steelespike]

Re: Completely confused about 3.0 alpha one prop replacements...

In reading various posts here:: speaking generically a typical 18' bow rider with a 3.0 would run about a 21" pitch for top end and a 17 or 18 for skiing and the like.The 17 would normally over rev in a light situation.Of course boat type,weight, bottom style typical load,motor condition would change these numbers.

 

[Rocky_Road]

Re: Completely confused about 3.0 alpha one prop replacements...

If I were in your shoes, I would automatically assume that the original owner has already done all of the 'legwork'...and was running the best prop for his setup.

Given the year of the boat...and the aftermarket items that has been installed (from your picture)...I would be shocked to find out that the owner totally forgot to pick the best prop pitch for his boat! Wouldn't make any sense....

Now...can you take his pitch choice, and upgrade the prop??? Say, to stainless steel, and variable pitched???

That's where I would be heading....

 

[HeloMech]

Re: Completely confused about 3.0 alpha one prop replacements...

Yeah, I guess that's a good point. I was able to talk with the previous owner, who apparently also got the boat used. He said the guy HE got it from, told him that it would pull a skier with that prop setup.

I stopped in to WestMarine and picked up the blackdiamond 15x17. I'll see what that does along with my GPS and make any adjustments from there.

Thanks for the input. He's supposed to bring in the manual, prop wrench and bring the registration current tomorrow.