pontoon boat prop question

O

oteps

Senior Member
I need a prop for a 24 ft pontoon with a 90 hp 4stroke mercury. The # on the prop is M?8 77338A45 11P. Im guessing its an 11 pitch? THe boat is used on the Susquehanna river, pull a tube with 1 person on it a lot. I think the boat could use some more top speed. What pitch should I be looking for? Is a stainless worth the extra money, it has an aluminum on it now? There is a lot of rocks to hit in the shallow parts.
 
oteps said:
I need a prop for a 24 ft pontoon with a 90 hp 4stroke mercury. The # on the prop is M?8 77338A45 11P. Im guessing its an 11 pitch? THe boat is used on the Susquehanna river, pull a tube with 1 person on it a lot. I think the boat could use some more top speed. What pitch should I be looking for? Is a stainless worth the extra money, it has an aluminum on it now? There is a lot of rocks to hit in the shallow parts.
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Yes, 11P = 11 Pitch. Stainless is more durable than alum, but also costs more. Too many variables to say for certain what pitch to use. I'd try to borrow a prop from your local marina or prop shop to check before I actually bought. Stainless flexes less than alum, so an 11 stainless will give you more bite in the water presuming everything else is equal (like cup, dia, rake, etc.)
 
pontoon props are generally very specific to the application, and they usually don't come in stainless. The biggest question, what rpm are you turning running wide open throttle average load?
 
Coming from somebody who grew up boating around nothing but rocks, oysters, and tree stumps, you will NEVER see a stainless prop on my boat if I'm boating anywhere NEAR those areas. As my dad told me, aluminum props are cheaper than prop shafts, and it's not hard to change a prop and be back under way. Yeah that stainless prop may survive the hit, but how about your prop shaft? I personnally would much rather tear up a $100 prop than an expensive prop shaft AND prop. That said, I've found MICHIGAN WHEEL to have some TOUGH aluminum props that can take someserious abuse, and many times they will just bend instead of breaking. Hammer it out when you get home, and you've got a great spare prop. Yes, I have a $500 powertech scd4 stainless prop for my skiff, but it stays under the bow when I'm flats fishing, and my $90 4 blade solas prop is bolted on for rock duty.

As to propping, that more so boils down to your current WOT RPM's. You need to prop it so the engine is runni,g inside the max wot rpm range at wide open(if it's a 4 stroke, it is reccomended to prop it so it runs on the upper end of it, or just over. You do NOT want to lug a 4 stroke unless you want to carbon it up, and chance it making oil). Michigan wheel sells some nice aluminum 4 blade aluminum props using the xhs hub system that come in lower pitch numbers for a pontoon boat. I like 4 blade props for big heavy boats that need alot of low speed thrust.
 
Looked up your prop number, and it's a 14x11 mercury black max entry level aluminum prop(not one of my favorites). It's supposed to use the flo-torque ii hub kit. If it does, I would say try the michigan wheel 941411. It's a 4 blade 11 pitch aluminum prop that also used a flo torque type hub. As a bonus, it can be had for around $95 with shipping vs $155 for the mercury prop. Don't knowif it would giveyou any more top end, but it should definately help with the hole shot and mid range running.
 
THEFERMANATOR said:
Coming from somebody who grew up boating around nothing but rocks, oysters, and tree stumps, you will NEVER see a stainless prop on my boat if I'm boating anywhere NEAR those areas. As my dad told me, aluminum props are cheaper than prop shafts, and it's not hard to change a prop and be back under way. Yeah that stainless prop may survive the hit, but how about your prop shaft? I personally would much rather tear up a $100 prop than an expensive prop shaft AND prop. That said, I've found MICHIGAN WHEEL to have some TOUGH aluminum props that can take some serious abuse, and many times they will just bend instead of breaking. Hammer it out when you get home, and you've got a great spare prop. Yes, I have a $500 powertech scd4 stainless prop for my skiff, but it stays under the bow when I'm flats fishing, and my $90 4 blade solas prop is bolted on for rock duty.
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Maybe, but around here we don't have the flats like you guys do. About the closest we come is the shoaling that occurs in Barnegat Bay all the time and for the most part it's all sand with an occasional shell tossed into the mix for good measure. Honestly in the Hackensack River I've hit quite a few submerged logs and pilings and by all accounts my prop shaft is still fine. Of course I'm usually going comparatively slow...(10mph or so) so maybe that has something to do with it. But that being said, I totally agree that an alum prop is much cheaper to replace than a SS and if you're boating in areas where there's lots of rocks then it just makes good (economical) sense to use an aluminum prop. :head:
 
I normally don't rev it over 5000, but it will go over but doesn't seem like u gain any speed. Just sounds like its reving way to high over 5. That's pulling a tube and 5 or 6 people on the boat.
THanks for all the info. Ill go with an aluminum one and probably try to find a used on on craigs list for a spare.
 
you need to prop it at or near the high end of the recommended rpm range. Run it wide open and see how many rpm it will turn. What year model is that engine? It should have a sticker on the tilt bracket that has the serial number on it and what the recommended rpm is
 
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