Will this prop fit my boat?

[thunderroad]

Greetings...I've got a 69 model Mercruiser 160 and have been wanting to try a 21P prop on it. A guy in the next town has one he wants to swap me, but I've googled until I'm blue in the face and can't determine if it will fit. He says the number is 48 63744A 21P. I can't seem to find any info regarding that number and was hoping someone here could point me in the right direction.
Thanks.

 

[Robbabob]

Re: Will this prop fit my boat?

He wants the prop on your boat and you want to try the prop from his? Next town over sounds pretty close to be able to work out a deal, "if it fits, it ships" Oh wait, a pun with the USPS. if his won't fit on yours, then yours won't fit on his. Can't hurt to try it out.

I'm guessing you've already checked your RPM and GPS speed to know that a change to a 21P is the right move in the first place. Just wanting a 21P doesn't mean it is going to help at all. In fact, your performance could be severely impaired. It depends on the data you could provide from one of the stickies at the top of the forum page. Give current prop, RPM at WOT, GPS speed, motor, boat, etc. We can then help you with the proper pitch... as far as it fitting, many others might know and they've not yet viewed your post.

Good luck!

 

[thunderroad]

Re: Will this prop fit my boat?

thanks for the reply. Actually it's on craigslist and he wants to trade it towards a guitar I have listed. He's not a boater and claims it was hanging in the shed of a place he bought. What I should have said is "I want to try a STAINLESS 21p on my boat". I've got an alum one but it's bent and dinged up, so I've been using my 19. A buddy went from alum to stainless and claims it's night and day, but I'd like to try one before layin down the cash for a new one. I was just tryin to come up with a way of knowing if it will fit before I drive over there. It's about 45 miles....not all that far of course, but there's really nothing else over there I need.
I guess I was just lookin for the cheap and lazy way out.

 

[Robbabob]

Re: Will this prop fit my boat?

Ah, okay.

now the fun part.... need information on your boat (length and weight), motor type and HP, max rmp for motor at wot, and your operating rmp at wot before the prop was too damaged.

Going from AL to SS "can be" like night and day, but it also can "mess you up" if you're not sizing the change properly. Usually subtract an inch or two in pitch when going to SS. Will be able to help better once you get us the details on your setup.

I know I haven't helped with your actual question yet. Kind of waiting for someone else to catch these posts that knows what may fit with what; I can help with proper sizing.

 

[fishrdan]

Re: Will this prop fit my boat?

A buddy went from alum to stainless and claims it's night and day

It's very possible that the aluminum prop wasn't a good match to his boat, while the SS prop was a very good match.... Put that same prop and engine on another boat and it could be a dog. I went from a 19P aluminum 3 blade to a 18P 4 blade and the difference,,, was like night and day.

I agree with Rob ^^^, you need to find out if the other guy's prop would be a good match to your boat, will the engine be able to obtain it's correct WOT RPM with the increased pitch?

Google turned up that P/N as a 21P SS prop, so it would be like going to a 23P aluminum

If your 19P prop is old, just buying a modern 19P prop could improve performance.