New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

[carman.d]

Non Bigfoot on a new Pontoon boat - prop change or motor change??
I've seen some threads similar - but really wanted some advice directly to my issues

Bought a new 20' pontoon boat (23" toons) last fall. She came with a 50HP EFI and a 10.3/8x13P prop, and no manuals on anything (boat, motor, trailer - nothing???) at a marine dealer.

Complained about the manulas pretty quick (as well as other things but that's another story). Took her out and she never seemed to perform the way I expected or was told - but I was a newbie, and with no manuals and my first pontoon boat - didn't investigate that much as I only had her out a few times that season.

This spring I started my research. I should be getting 5500-6000 rpm WOT - getting 4000. Very sluggish (obviously). Researched the prop and merc prop picker tells me I should have 12.25x9Pitch prop which sounds about right for my RPM's. I was pretty upset (new 20k boat) and contacted the dealer. They were willing to get me a new prop but questioned my prop numbers. This lead me to further research - which told me that many people think that anything but a bigfoot on a new toon is rediculous at best???
I have been pressuring the dealer to cut me a MAJOR break on a 60HP Bigfoot. I actually called the boat manufacturer and one of their salespeople said they would never sell that boat with a non bigfoot motor???
Dealer is bucking this and saying it was "not wrongly equipped". They offered to upgrade the motor for $3300 plus labour to swap. I countered offering to pay the difference between the engines ($1500) but feel they should eat the loss on my now used (barely) motor and labour to swap them.
Am I being unreasonable??
Would the 12.25x9P prop fix the issues and give me decent performance?
Or am I likely to have ventilation problems at higher throttle because of the shorter shaft?

thanks in advance for your help and advice on this.

 

[5150abf]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I work at Benninton marine and we sell thousands of boats every year without Bigfoot engines, some have them but the majority are Yamaha powered, I am geussing that you got a Tracker and they are owned by the same company as Mercury so they all wear Mercs.

Really any 50 correctly propped should do fine on your boat, as I said 98% of all the pontoons I see on the water aren't running bigfoots and do fine.

Have your dealer check the engine it may not be running right and that is the cause of your problem, you would think dealing with them every day the dealer would have a pretty good idea what prop should be on your boat, not coming down on either side just saying, you looked on your computer and this guy actually deals with boats every single day.

Switch props and see what that does but keep in mind you have a 50 horse on a 20' boat with smaller tubes, you can't expect super hole shots and tons of top end speed.

Change the prop.

 

[Jeep Man]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

Your last sentence says everything. 5150 is usually quite observant, but perhaps he missed this one. A Bigfoot is a 20" shaft, and any motor can be ordered with a 20" shaft, but are you saying yours is a short shaft? Your pontoon and most all pontoons require a long shaft motor. With a short shaft, prop ventilation is imminent.
BTW, I have a 20' with a 60 Bigfoot. Wish I had gone with the 90. Consider bigger if your upgrading.

 

[lncoop]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

9" pitch? Interesting. I just spun through (like that?) Merc's prop finder and came up with 12"/13" for your setup. I had to make a couple of assumptions, but since you told us it's a 20' barge with a 50 horse EFI and you used Merc's website I can't imagine what I could be missing. What did you plug in to come up with 9"?

In any case, every 1" drop in pitch generally results in an additional 200 RPMs, which means dropping to a 9" would only yield another 800-1000, getting you to 4800-5000, still well short of your max recommended RPMs. You might as well go ahead and try a different prop since the dealer is willing to provide you with one, but there could be something else wrong. Work with your dealer to get it right. Good luck.

 

[lakegeorge]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I think you should get about 20mph with your set-up, I also think the dealer should do whatever it takes to get your motor to run around 5,600 rpm's and then see if you can live with it.
I also think you should find the ser #'s on your motor to see what you have, then talk to the mfg. and see if they agree with the set-up.

 

[carman.d]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

A Bigfoot is a 20" shaft, and any motor can be ordered with a 20" shaft, but are you saying yours is a short shaft? Your pontoon and most all pontoons require a long shaft motor. With a short shaft, prop ventilation is imminent.
BTW, I have a 20' with a 60 Bigfoot. Wish I had gone with the 90. Consider bigger if your upgrading.

I had thought all bigfoots had the longer shaft - but now looking on the merc website I see that the 50elpt and 50bigfoot BOTH have a 20" shaft. Only the 60BF is available in a long shaft. So does that mean gear ration and ventilation plate is the only difference? Maybe the larger prop would solve the problem??
I still can't go to a 14" without the bigfoot - but 12.25" is a lot bigger than the 10.4" I have now.

 

[carman.d]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

Incoop - I just did it again?? Merc prop picker - pontoon, best overall performance, 50ELPT at 2009(they don't have 2011?), 20'length (just went with length to simiplify), and it spits out 12.25x9P, and a couple of others in the 11x10P range. I had thought with the larger diameter prop and a change in pitch - I would get more varied results and might see a 1500+ change in rpm??? I'm not sure - I could go down to 8P, but I thought I should take such a major change one step at a time. Since we are SOOO far off ideal rpm - might as well start with what merc says I should have.

 

[lncoop]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

Like I said, I didn't have all the ingredients and had to make a few assumptions, so my results may have varied. It's definitely worth a shot. Hope you get it worked out in time to to have a good summer of boating. Keep us posted.

 

[noticon75]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

OK I am a noob with boats BUT has the motor been broke in? The reason I ask is while at the marina the other day they were breaking in their new toon and the motor would only rev up to 4500 and they said that is part of the break in on the motor and they had like 5 more hours till the computer would let the motor rev up. Please do not take this as gospel but Just a thought.

 

[Jeep Man]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I had thought all bigfoots had the longer shaft - but now looking on the merc website I see that the 50elpt and 50bigfoot BOTH have a 20" shaft. Only the 60BF is available in a long shaft. So does that mean gear ration and ventilation plate is the only difference? Maybe the larger prop would solve the problem??
I still can't go to a 14" without the bigfoot - but 12.25" is a lot bigger than the 10.4" I have now.

The only difference in your motor and a Bigfoot is the bottom end. Bigfoot uses the gear ratio, gears and shaft that is used on the 75 and 90. The "L" in ELPT indicates long shaft. The heavier gears and shaft allow it to turn a bigger prop without breaking. Check with your dealer to see how big you can go safely.

 

[carman.d]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

Thanks everybody for your input. I had to eat a little crow - but I just emailed the dealer and apologized for telling them they put the wrong motor on the boat. I read a few threads where guys were really slamming dealers that put a non bigfoot on a pontoon and talked to a sales guy at sunchaser - and that got me all worked up LMAO, but it's more opinion than fact - the 50ELPT should do fine with the right prop.

I'm going to go with the 12.25x9P prop, make sure she's all the way down on the mount, and see what she does! I'm hoping that will do the trick - by the old 200rpm/inch thing it's not quite enough - but it's also such a major change that I don't think RPM can really be predicted at this point (1.75" larger prop and 4"of pitch is a big change).

I will let everyone know what the end result is and try to GPS my speed - that way the next poor sucker that comes along will have an idea what to do.
thanks all
Carman

 

[lncoop]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I'm glad you made peace with the dealer. Sadly most people wouldn't bother. Integrity and a willingness to concede when appropriate seem to be disappearing qualities in a man these days. I find it very troubling, but I digress. So, what about the break in period noticon mentioned? Is the motor a four stroke?

 

[DJ]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I'm glad you made peace with the dealer. Sadly most people wouldn't bother. Integrity and a willingness to concede when appropriate seem to be disappearing qualities in a man these days. I find it very troubling, but I digress. So, what about the break in period noticon mentioned? Is the motor a four stroke?

Yes, that's a good thing.

I don't see ANY issue with not having a Big Foot. I think 50 HP is a little light for a 20' Toon though. It all depends on what you want to do do with it.

My family owned two Starcraft 20 footers. Both with 75 HP Merc's. One w/2 stroke, one w/4 stroke.

Both ran at the right RPM's with 12" (pitch) prop's. So, I think you're close with your 9" estimate.

 

[lmuss53]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I had a 50 Evinrude on my 19 footer and always go loaded down pretty heavy. I ended up with an 11p prop to get 5500 and 19 mph with just me on board. The 9 is not far off I think, good luck and have fun. The 50 is pretty small for the 19 or 20 footer, any additional weight will slow it down pretty quickly.

 

[mayorjones]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I have a 2008 21' Sun Tracker that had a 50 HP Long Shaft Merc and it absolutely would not run with it on there. Mounted as low as possible and trimmed all of the way down it would cavitate/ventilate horribly. We boat on the Mississippi where the current can be pretty strong and going against the current there were times I questioned if we would make it back to the dock, and that was with everybody in the back of the boat.

I traded it for a 60 HP Bigfoot and have had no problems. It isn't as fast as I'd like, and reading this has me wondering if I might try another prop as well. I can get close to 6,000 RPM when it's just me in the boat, but when I have others along, which is almost always the case, it gets just above 5k and I'd like to bump that up a little.

So, what do you guys think - if a motor is rated for 5500-6000 RPM, should that be based on "normal" situations (several people on the boat) or best case scenario? It wouldn't hurt me to have an extra prop anyway, but want to do the smart thing here...

Please advise.

Thanks.
Dwight

 

[rrhodes]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

OK I am a noob with boats BUT has the motor been broke in? The reason I ask is while at the marina the other day they were breaking in their new toon and the motor would only rev up to 4500 and they said that is part of the break in on the motor and they had like 5 more hours till the computer would let the motor rev up. Please do not take this as gospel but Just a thought.

LOL,.. um no.. Before or after break in the motor will not rev an extra1500 rpm and the computer does not regulate that. They were not propped right. I might believe 100rpm but the break in is more important to the longevity of the motor than anything else.

 

[lncoop]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

So, what do you guys think - if a motor is rated for 5500-6000 RPM, should that be based on "normal" situations (several people on the boat) or best case scenario? It wouldn't hurt me to have an extra prop anyway, but want to do the smart thing here...

Please advise.

Thanks.
Dwight

Base it on your most consistent type of use. It certainly won't hurt anything to try a different pitch. If you don't like the results the dealer will most likely take it back as long as there's no damage.

 

[rutcutter]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

Carman, I also have a 20 foot toon with a 50 HP non bigfoot. Mine is a 50 Mercury 2 stroke. When I got it there was a 10.5 " pitch Mercury prop on it and it was not getting to the max RPM like it should. I went to a Turning Point prop # 1208. That is a 12" diameter with an 8" pitch and it made my RPM perfect. I was getting 4200 max with the old prop.
Now, that having been said, if you are going to the expense and trouble of changing motors go with a 90. You will be much happier. My motor runs good but I still wish I had a 90 which is max HP for my boat.
Good luck.

 

[James Starr]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

I must just be lucky i have a 2000 21' sun tracker with a 40hp mercury 2 stroke it will run 20mph on a smooth day with just me in it i have no cavitation or ventilation at all with the whole family in it wife and three kids it will only do about 15-17mph, but i sure wish i had a 90 or 115. I think my prop is a 13/10.

 

[mayorjones]

Re: New pontoon with a non bigfoot motor low rpm's - prop change - or motor change??

So guys - to continue my thought from earlier. If I was going to try another prop, for a 2008 Mercury Bigfoot 60hp, what would be my desired RPM - somewhere just under 6k WOT?