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2010 2250 RCW w/ 150 Yamaha running slow?

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Brad Davenport

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ok, new to the club here, but have had my Benny for 4 years now. When I’m on glass, my GPS top speed is 27mph with 2 adults and 2 small kids and 1/2 tank of gas, trim 3/4 up. My RPMs do not get over 5000. I cannot remember which prop I have, but it is the one that came on it. I thought it may be the fuel injectors clogged, so I replaced them with same results. Should I get more speed on this thing? Other threads are saying they get 34 mph with the same setup. I know there are many variables in this stuff, but any thoughts??
 
Brad Davenport said:
ok, new to the club here, but have had my Benny for 4 years now. When I’m on glass, my GPS top speed is 27mph with 2 adults and 2 small kids and 1/2 tank of gas, trim 3/4 up. My RPMs do not get over 5000. I cannot remember which prop I have, but it is the one that came on it. I thought it may be the fuel injectors clogged, so I replaced them with same results. Should I get more speed on this thing? Other threads are saying they get 34 mph with the same setup. I know there are many variables in this stuff, but any thoughts??
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Brad, what type of pontoons (SPS, ESP, etc)?
 
Yes, it sits in the water full time. I do need to clean the toons, but I had the same result after I polished (which I Wil never do again) the toons. You could literally shave in them. They looked like mirrors.
 
Brad Davenport said:
How can I tell which ones I have? I do have in floor storage on the middle toon, if that helps.
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Not sure how to tell which toon package, but it is a tritoon. I think you should look at your prop first as an easy thing to check. Too high a pitch will keep your rpm's down. Max RPM's on a 150 should be higher than 5K.
 
MikeOnTheLake said:
Not sure how to tell which toon package, but it is a tritoon. I think you should look at your prop first as an easy thing to check. Too high a pitch will keep your rpm's down. Max RPM's on a 150 should be higher than 5K.
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Yes, this motor is 5000-6000 rpm WOT
 
In a tritoon, you should absolutely be hitting those mid to high 30’s with a Yamaha 150. Based on you saying your RPM’s are not getting over 5000, I’d have to agree with others. Also, do you know if it’s an aluminum or SS prop?

It sounds like you have too large of a pitch prop, assuming its SS. If its aluminum, that would then be the other part of the issue holding back performance.

The rule of thumb is generically you will increase 200 RPM’s for each -1 in pitch size that you drop down on a SS prop. That can vary, but it’s a workable ballpark. You might also have your engine mounted to low into the water creating more drag too, but I’d start with getting a better prop, and better prop pitch.

Below are two prop selector’s you can use. They are not precise, but they will help you get into a pretty decent ballpark on what props to consider for your boat and boat use. Good luck!

https://www.mercurymarine.com/en/us/propellers/selector/

http://www.yamahapropselector.com/propSelector/web/
 
Vikingstaff said:
In a tritoon, you should absolutely be hitting those mid to high 30’s with a Yamaha 150. Based on you saying your RPM’s are not getting over 5000, I’d have to agree with others. Also, do you know if it’s an aluminum or SS prop?

It sounds like you have too large of a pitch prop, assuming its SS. If its aluminum, that would then be the other part of the issue holding back performance.

The rule of thumb is generically you will increase 200 RPM’s for each -1 in pitch size that you drop down on a SS prop. That can vary, but it’s a workable ballpark. You might also have your engine mounted to low into the water creating more drag too, but I’d start with getting a better prop, and better prop pitch.

Below are two prop selector’s you can use. They are not precise, but they will help you get into a pretty decent ballpark on what props to consider for your boat and boat use. Good luck!

https://www.mercurymarine.com/en/us/propellers/selector/

http://www.yamahapropselector.com/propSelector/web/
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Thank you! I just went back to some pictures of when I got it, and the motor is as low in the water as it can get (from what I can tell). Am I looking at this pic correctly? I also read somewhere that it needs to be higher than this out of the water. And, yes, it is a stainless steel prop.
 

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Brad Davenport said:
Thank you! I just went back to some pictures of when I got it, and the motor is as low in the water as it can get (from what I can tell). Am I looking at this pic correctly? I also read somewhere that it needs to be higher than this out of the water. And, yes, it is a stainless steel prop.
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For motor mounting you want to look at where your cavitation plate is at in the water when you are underway...at speed. Is it basically at the water line, then you are solid. If you cannot see it at all, its underwater, and your motor is mounted too low. Is it up higher and there is a gap between it and the water, its too high, and you probably blow out at times more often.

It seems like the issue is the wrong prop size or type or both. Thus, I’d focus in that direction, but motor mount could be part of it. Chances are its a bit too low, so its creating too much drag, and not good on that lower unit.

But the RPM issue and speed is most likely prop related.
 
Vikingstaff said:
For motor mounting you want to look at where your cavitation plate is at in the water when you are underway...at speed. Is it basically at the water line, then you are solid. If you cannot see it at all, its underwater, and your motor is mounted too low. Is it up higher and there is a gap between it and the water, its too high, and you probably blow out at times more often.

It seems like the issue is the wrong prop size or type or both. Thus, I’d focus in that direction, but motor mount could be part of it. Chances are its a bit too low, so its creating too much drag, and not good on that lower unit.

But the RPM issue and speed is most likely prop related.
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Thanks. I’m heading to the boat this weekend so I will take a straight edge and place on the bottom of the center toon with the motor fully down to see where the cavitation place sits to get an idea, then check it while cruising to see how it looks. Also to get the dimensions on the prop.
 
Like the others said, 5000 rpms seems low. And I completely agree with everything Vikingstaff said.

Just like a car, the faster the engine rpms the faster the speed. Ideally you want to target the upper end of the rpm range under the conditions which you normally use the boat (such as heavy load vs light load).

Snap a pic of the back end of the hull and post that here with your prop info. Most of the members here will be able to identify the hull model for you. Your engine pic looks like an SPS or ESP hull. Someone may be able to tell from that pic.
 
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By the way, I totally understand your comment about never polishing the toons ever again! Been there myself. Your comment made me laugh. It's been a few years, so I can laugh at that mistake now!
 
kaydano said:
By the way, I totally understand your comment about never polishing the toons ever again! Been there myself. Your comment made me laugh. It's been a few years, so I can laugh at that mistake now!
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Yeah, I wanted them to look good. They previous owner never touched them. It was a tremendous amount of work, however, even after 4 years, they still look better than when I got it. I will be heading up to the boat this weekend and will gather more information.
 
Please post an update to this thread when you have experimented. I'm in a similar situation. I have a new 2019 Bennington with 150 Yamaha and get 32 mph at 5200 rpm WOT. I'm pretty sure my issue is prop. Mine says 15-M and 14 1/2 under that.
 
Brad Davenport said:
Thanks. I’m heading to the boat this weekend so I will take a straight edge and place on the bottom of the center toon with the motor fully down to see where the cavitation place sits to get an idea, then check it while cruising to see how it looks. Also to get the dimensions on the prop.
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Ok, I cannot see the cavitation plate while cruising, however, when I got in the water, the cavitation plate is about an inch below the bottom of the center toon. Also, my prop is a 14 3/4 x 17.
 
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