Happens both from a stop and while slowly increasing speed
My new 22sxp is a BIG disappointment
- Thread starter mosesjb2
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I agree with you, the boat itself is very nice indeed.
I like the materials and stuff, I am just disappointed in the performance.
Thanks for your input
Do you know exactly which prop is currently being utilized - diameter and pitch?
I checked the Merc Prop Selector using the basic specs for your model from the Bennington website as well as selected Command Thrust, and here were the suggestions:
If you want to run through it, here is the link:
Mercury Marine - A Worldwide Leader in Marine Propulsion | Mercury Marine
Manufacturers of outboard motors and MerCruiser inboard engines, with over 4000 dealers in the United States.
www.mercurymarine.com
This is merely to eliminate the prop, itself, as being part of the problem because it could be a combination of engine height and prop.
If your current prop is spec'd near any of those (or is a prop that is inarguably best suited for your particular BoW), then I would lean towards agreeing with what others have said about the engine being mounted too high for the operating conditions, assuming it has a 20" shaft instead of the 25".
There's also the possibility of something mechanically wrong with the drive.
Frustrating for sure but, all in all, definitely partner up with your dealer to allow them the chance to make it right.
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PartyBarge
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Wow, could it be that someone not only put the wrong type motor on the pontoon, but mounted it up one hole too?????? That would seem to be a rather significant QC issue.....
thirdchild
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I bought a new 2018 Bennington dual log with no lifting strakes pontoon (22 SSBXP) in the summer of 2018 with a new Mercury 115 command trust 20 inch motor. The pontoon was set up from the dealer with a 3 blade Stainless steel Mercury Enertia 15.0 X 15P RH prop. The pontoon ran ran 29.5 mph (5900 RPM) two weeks ago with 2 people on board trimmed out A small amount. This boat has an excellent hole shot.
This boat loaded with 6 or 7 adults will only top out at approximately 22-23 mph. If operating the pontoon with the lower unit all the way in the prop does not slip or break loose. If operating the pontoon with with one mark on the trim gauge it will definitely slip. The outboard is mounted with the pin in the top hole. If there are only a few people in the boat I can get up on one ski with this prop set up. I am very happy with the performance considering I only have a 115 hp and not a tri toon. I hope this is of some help to you. Good luck!
This boat loaded with 6 or 7 adults will only top out at approximately 22-23 mph. If operating the pontoon with the lower unit all the way in the prop does not slip or break loose. If operating the pontoon with with one mark on the trim gauge it will definitely slip. The outboard is mounted with the pin in the top hole. If there are only a few people in the boat I can get up on one ski with this prop set up. I am very happy with the performance considering I only have a 115 hp and not a tri toon. I hope this is of some help to you. Good luck!
thirdchild
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Nice Benny. 3C!
goldnrod24
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Congrats on your purchase and the performance you have obtained. It's very remarkable for a 2 tube/115 combo. I do want to caution readers of this thread that the purpose of a stainless steel prop is to prevent blade flex on higher horsepower motors. There is no performance advantage to installing a stainless prop on an outboard of less than 150 hp.
Happy boating.
PartyBarge
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Congrats, you must be using a "big boy" ski. Attempting to slalom on my regular ski at anything less than ~32 MPH is very tiring and just asking for a crash!
thirdchild
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Yes, you are exactly right, I have to use a wide body ski behind this 115hp set up. We call this ski our clown ski. Whatever works
PartyBarge
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Yeah, fun stuff. I guess you aren't going fast enough to be of much concern. But if you are generating some good crossing speed, be ready for a ski like that to fly like a wakeboard...don't ask me how I know that.....
Thanks so much for your reply and information concerning my issue with my boat.
Luckily for me my boat is nearly identical to the one you posted online.
I checked your photos and noted the following differences:
I appear to have the same engine, Mercury CT 115 with numbers near the bottom as follows: 13x31 2.38:1
The prop I have is a Mercury Black Max P/N 48-78116A45 15.25 x 15 pitch 3 blade aluminum
Also, my engine is mounted one bolt hole higher than your engine.
It appears I will need to get the engine lowered before putting the boat back in the water for next season.
I really would rather have an aluminum prop as the lake water can be a bit shallow.
Thanks again for your input
Thanks for your reply on my issue.Do you know exactly which prop is currently being utilized - diameter and pitch?
I checked the Merc Prop Selector using the basic specs for your model from the Bennington website as well as selected Command Thrust, and here were the suggestions:
View attachment 28075
View attachment 28076
If you want to run through it, here is the link:
Mercury Marine - A Worldwide Leader in Marine Propulsion | Mercury Marine
Manufacturers of outboard motors and MerCruiser inboard engines, with over 4000 dealers in the United States.
This is merely to eliminate the prop, itself, as being part of the problem because it could be a combination of engine height and prop.
If your current prop is spec'd near any of those (or is a prop that is inarguably best suited for your particular BoW), then I would lean towards agreeing with what others have said about the engine being mounted too high for the operating conditions, assuming it has a 20" shaft instead of the 25".
There's also the possibility of something mechanically wrong with the drive.
Frustrating for sure but, all in all, definitely partner up with your dealer to allow them the chance to make it right.
I have a question, how can I tell which shaft the engine has, 20 or 25"?
It has 13x31 2.38:1 on the out drive and is a Mercury 115 CT engine.
Also, I noticed the props you listed and wonder if any aluminum ones would be comparable.
Thanks again.
The shaft length designation will be in the engine model number:
115 ELPT = the "L" means long shaft/20"
115 EXLPT = the "XL" means extra long shaft/25"
There should be a plethora of aluminum options available, but I'd take the advice mentioned earlier by Potomacbassin’ and Vikingstaff to reach out to Prop Gods to ensure that they give you the best service and recommendation for your specific needs, desires, and usage.
Boat Engine Propeller Testing Services - Prop Gods
Reach out to the dependable team at Prop Gods to ensure that your boat engine propeller is in peak condition. Learn more.
propgods.com
PartyBarge
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I haven't noticed it mentioned that the Merc 115 CT (Command Thrust) has the larger lower gear housing (same as most 150 HP and larger motors), not the smaller lower diameter of most 115 HP motors. As you are looking for props, be sure to mention that. Sounds like the general purpose Black Max can't hold that motor/gearing, especially if mounted too high.
I spoke with Ken at prop gods and he mentioned an issue that some people have had is there are things attached to the engine mounting pod on their boats which cause increased turbulence in the water flow while going thru the water. Anything that disrupts the smooth flow of water along the surface can add to the problem. My boat is still in storage, but seems to me I remember seeing a strange few pieces of metal welded to the inside surface of the engine mounting pod just forward of where the water would flow out of it. I will be checking this out soon. Thanks again to everyone for their help on this item.
Spoiledrotten
Well-Known Member
This is another vote for a setup issue. The person at the dealership is selling boats because he just got fired from his garbage truck job. There are just a few main things to be dialed it. It’s not a Bennington issue, and it’s not a pontoon issue. It’s an individual boat issue. Be patient and until it’s fixed, remain below the speeds that create the frustration for you. You’ll get there! Beautiful boat, BTW.
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mng8r
Active Member
Perhaps I missed it, but reading through this thread I didn't see mention of the trim level of the motor. Does the behavior change if the trim level of the motor is changed?
Superphil69
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I had an issue similar to this when I had a 115 on a previous 2019 boat.(2 toon)
3 things came up from Harris dealer and Engineer form Mercury.
Strakes were 2 long, causing too much lift
Motor was too high but when lowered did not fix(dealer tried almost every position.
Motor was not an XL
Went to a 150 XL and problem went away
I know that there are a lot of things different here, but the theory may be the same.
Prop was a SS 14 pitch on Both
3 things came up from Harris dealer and Engineer form Mercury.
Strakes were 2 long, causing too much lift
Motor was too high but when lowered did not fix(dealer tried almost every position.
Motor was not an XL
Went to a 150 XL and problem went away
I know that there are a lot of things different here, but the theory may be the same.
Prop was a SS 14 pitch on Both
Update:
I just got my boat out of storage and checked the pod on the bottom of the boat, Bennington has like nearly all boat manufacturers now moved the gas tank to the center pod of the boat. At least Bennington kept the gas fill location the same on the side of the boat. Thank you very much!
Anyway, I have attached some photos showing a piece of metal mounted directly behind the gas tank. Any one have any clue what this is for?
People are telling me this could be contributing to the air bubbles entrained in the water flow resulting in the blow out being experienced when trying to get to full speed.
Does anyone at Bennington have any idea what this piece of metal is for? Can it be removed or what?
I have my dealer coming out to see what I have been talking about with the blow out issue. The feedback from the dealer makes it sound like he thinks I am out of my mind that all pontoons have these issues. I say he doesn't know what he is talking about. The engine needs to be lowered to the last mounting hole as a place to start.
If I am the only one on the boat I have no issue, but as soon as anyone sits toward the front of my boat it can not get over 5000 rpm and blows out.
I plan to update again soon.
