Mercury 75, 90, & 115 HP 4-Stroke Propeller Replacement - the rookie's perspective and learning(s)

Video of a rookie (me) changing a prop on a Mercury 75 HP 4-stroke (attached to a 2021 Princecraft Vectra 19 Pontoon), and some of the learnings along the way: prop selection, pitch, hub adapters, RPMs, tools needed, etc.
A Mercury 13.8-11p Spitfire prop was destroyed on a sandbar (rocks), and replaced with a Turning Point Propellers, Hustler Aluminum 4-blade (14-13p).

[@bobobrien9183]

E tremble y well done. Tons of thanks!

[@michaelphinney9294]

Good video, I highly recommend this to everyone.

[@richardstaehle6134]

Good video. I'll mention that once the prop is removed as shown you should pay attention to the white plastic prop "bore ring" that remains on the lower unit. It snaps into place and should be secure against the lower unit. The fingers (snaps) do have history of breaking and if the bore ring is loose it can cause cavitation of the prop. A number of YT videos show this. A replacement if needed can be got for about $6-8. Cheers!

[@beebee7999]

Great to know. Thx for the info!

[@dpliu1]

The plastic hub is designed to crack to prevent damage to the outboard. I just learned that and wanted to pass it on. 👍

[@beebee7999]

Good info!

[@7277AdiBoy]

Do you have a link to that prop? And is it faster than the one before?

[@beebee7999]

Hi Eddie. The prop is from Turning Point (a Hustler prop). Address here: turningpointpropellers.com/ ...Unfortunately the one I put on in this video was not faster. Going to a slightly larger prop (fraction of an inch), but in a 13 pitch, should have decreased RPMs by a few hundred from stock prop and I hoped for more top end speed accordingly. However, my wide open throttle (WOT) RPMs dropped to 4800 which is just too low for this Merc. I guess the 75 HP just doesn't have the ooomph to push it. I swapped over to the Hustler-Turning Point prop that's a 14" x 11P, and I am back up to 5200-5300 RPM at WOT. I gained about 4 knots going back 'down' to the 11 pitch in the same diameter. I was surprised that it was a full 4 knots difference. I kept the 13 pitch as my new spare in the boat.

[@javery50]

@@beebee7999 if the merc is rated at 6000 I would go down another 2” of pitch. The way I prop is max rpm empty that way when I put a load in the boat I’m not lugging the engine.

[@beebee7999]

@@javery50 worth another "test" when I destroy this one on something... LOL.

[@opticmanz]

@@beebee7999 going to a bigger diameter prop will reduce top end speed due to increased drag.

[@michaelscottroberts5444]

Very well done instructional video, friend. There are several other videos on YT that skipped steps, or performed steps Off Camera, which leaves a novice having to search further for details (such as inserting the hub sleeve, greasing the splines before replacing the prop, etc...) You did not skip steps; you were thorough, did everything in front of the camera, and it's very much appreciated. The floating prop wrench was particularly good advice!! I'm having to do this job myself and a grateful for having found you. Happy boating and thanks again.

[@beebee7999]

So glad to hear this was helpful! Happy boating! I’ve got too many more months of frozen lakes in front of me and am jealous of those of you still on the water. :)

[@stevengrundt5387]

That was great. Just what I needed, same exact thing happened to me. Thanks.

[@beebee7999]

And hopefully happens to neither of us again. ;) Happy boating!

[@carolinacoins]

You have good knowledge for a rookie. I appreciate your attention to details. I am not a rookie boat owner, but have never carried a spare prop. Thanks to you, I will now. Thank you for taking the time to make this video and sharing it with us. Happy boating my friend.

[@beebee7999]

Thanks for the kind words! I’m definitely learning on the fly, and happy to hear this was of some benefit. If it saves one person from a day of trouble, it’s worth it. :)

[@osmosisdaily]

Thanks for documenting. Good information

[@beebee7999]

Glad it was helpful!

[@TheBoneruner]

How did the new prop work out?

[@beebee7999]

Not too bad. It’s had good use since the change. I feel like I have more hole-shot. BUT I definitely feel like sacrifice is a teensy bit of top end speed (and that annoys me). The difference between this and the OEM Mercury Spitfire in terms of pitch and size and numbers is minimal. But the Spitfire was a better prop at 5500 RPM. That said, for the cost savings, I’d go this way again every time.

[@dirtybootsfishing2923]

It look like yourlower unit is got a gap in it isnt it supposed to but up against each other 😂😂😂

[@beebee7999]

Nope, all good. 1.5 years later and the lower end is still happy as a pig in poop (or a fish in water).

[@TheTheMo27]

Where do I get adapter

[@beebee7999]

Sorry! I'm not sure what you're referring to but I'd start with a local marine shop first. #SupportLocal

[@duanetwining9479]

I think he’s talking about the ring to being the diameter of the new prop to the old one so exhaust doesn’t leak.