Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

[pavandy]

I have a Mercury 50 HP ELPTO outboard motor that runs a 22' pontoon - Crest II DL. Just got it and need to replace the prop. Cannot read any markings on the existing prop. I have received many types by using web based charts. Anyone out there have experience with the correct Prop to use for my 22 foot Pontoon ? Thanks

 

[Silvertip]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

What your pontoon make and model is has little to do with prop selection. There is no such thing as a standard prop so one needs additional information to determine what that prop should be. Every engine manufacturer specifies what the recommended wide open throttle rpm range is for every one of their engines. So your job is to first determine what that number is. I suspect the range is 5000 - 5500 for your engine. That is the RECOMMENDED rpm range. Your next job is to determine what the WOT rpm for your boat with what YOU consider and "average load" is. You can only determine that if your boat has a tachometer. The third job is for you determine what prop you currently have. I've never seen a prop that you could not read the numbers on (if there were numbers) so look again. The fourth job is to tell us whether you have a Big Foot motor or a standard. If the motor is a Big Foot it will say so on the cowl. The Fifth job is to tell us the year of this 50 HP Merc. Theya re not all the same you know! Armed with this information we stand a reasonable chance of helping. Without it your guess is as good as ours. The point is, you need a prop that puts the WOT rpm at or very near the top of the RECOMMENDED rpm band with an average load. If the engine overrevs, you need more pitch. If it cannot reach that RPM you need less pitch. Speed will be whatever that prop provides.

 

[rschap1]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

Just for a off the cuff round about suggestion w/o more details...
I have a 2 stroke 75 on a 22 foot 'toon.
I have a Michigan Wheel that is like 13 1/2" diam x 13" pitch.
I would GUESS something similar, possibly an 11" pitch would be ball park for you.
Michigan Wheel's site has a prop selector feature that you could check too.
I think Mercury has something close too.

 

[Bamaman1]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

Good information. Their experience is right on the money.

You want to prop it for the maximum rpms' to match the specs for the engine with 2-3 people and 1/2 tank of fuel. If you find your serial # plate, it may have the rpm range.

Check your local market to see if you have a prop shop. Those guys have enormous knowledge and experience in propellers and can tell you the best prop for your specific need. And, their experience doesn't cost you anything. You're going to have to buy the prop from someone, and aluminum props are not very expensive items.

 

[Silvertip]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

One important factor here is whether or not the OP's engine is a Big Foot or not. There are lots of pontoons running with standard 1.83:1 (non-Big Foot) lower units. That engine runs a 10 inch prop whereas the Big Foot motors have a 2.34:1 gear set and can swing a 13 - 14 inch prop which is much better for pontoon service.

 

[Jeep Man]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

I have a 60 Bigfoot with a 14x11. i would expect you would also have an 11 pitch with with a smaller diameter if yours is a non-Bigfoot model.

 

[Silvertip]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

I have a 60 Bigfoot with a 14x11. i would expect you would also have an 11 pitch with with a smaller diameter if yours is a non-Bigfoot model.

I doubt that because on a V-hull fishing boat the common prop is a 13P. I've seen lots of 14x9's on Big Foot pontoons.

 

[pavandy]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

I doubt that because on a V-hull fishing boat the common prop is a 13P. I've seen lots of 14x9's on Big Foot pontoons.

Ok, I've heard many suggestions. The Mercury dealer suggested a 12.25 x 8 or 9 pitch. I've heard a 10.7/8 x 11 among many other sizes on forums.
This is a 2003 mercury 50 hp ELPTO model #1050412AD. The Max RPM's is 5500 stamped on a plate on the motor. On the motor low end it has a sticker that reads 12x22 1.83:1. It's a two stroke 3cyl 40/50 Jet30n according to the serial number. 22' crest II deluxe pontoon. The normal load will be about 7 adults, It has a 12 person capacity. Boat weighs 1980# empty. Hope I did all my homework for you Silvertip! lol Just looking for some info before I order a prop. Probably going to get a stainless steel with an aluminum spare. Thanks guys for any help you can provide. I appreciate it.

 

[Jeep Man]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

I doubt that because on a V-hull fishing boat the common prop is a 13P. I've seen lots of 14x9's on Big Foot pontoons.

I also have a 14x9 that is my spare. Had a tendency to over rev. RPMs can easily go over 6200

 

[Silvertip]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

Ok, I've heard many suggestions. The Mercury dealer suggested a 12.25 x 8 or 9 pitch. I've heard a 10.7/8 x 11 among many other sizes on forums.
This is a 2003 mercury 50 hp ELPTO model #1050412AD. The Max RPM's is 5500 stamped on a plate on the motor. On the motor low end it has a sticker that reads 12x22 1.83:1. It's a two stroke 3cyl 40/50 Jet30n according to the serial number. 22' crest II deluxe pontoon. The normal load will be about 7 adults, It has a 12 person capacity. Boat weighs 1980# empty. Hope I did all my homework for you Silvertip! lol Just looking for some info before I order a prop. Probably going to get a stainless steel with an aluminum spare. Thanks guys for any help you can provide. I appreciate it.

OK -- this the info we need but you are still missing the most important number. What RPM does the engine turn with the prop you have NOW! Don't worry about diameter. As pitch goes up diameter comes down and vice versa. Just buy a prop for your specific engine which as I suspected is NOT a Big Foot. You will definitely be looking in the 9P range. Using 12% slip, a theoretical speed of 20 MPH and your 1.83 gear set an 9P prop would be needed. 11P would be way too much pitch considering a 13P is the typical prop for a V-hull.

 

[WaterDR]

Re: Help ! Needing a Prop Suggestion for my Pontoon Boat !!!

I am no pro, but the more I have learned and folks I have talked to, the bst way to know if the prop is correct, is to actually test it!

the worst case scenario is actually a light boat because the rpms will be the highest. Every water test I have read states to take the boat out with one person, half tank fo fuel, put the trim the motor all the way down and then go to WOT. The motor should spin right up to max rpms. Then, try planing the boat out by triming the motor. The rpms may increase. this test will tell you how much power you are leaving ont he table vs how much you need to throttle the motor back.

In my case, my motor will hit 6,000 using this test, and will increase above 6200 when i trim it up, so i need to throttle back a bit. When loaded with 4 or 5 people, the rpms stay down further,so not an issue. The max rpms on my motor is 6200.

In my case, I am considering a prop with a larger pitch. but, i may end up giving up too many rpms when loaded.