2275GCW Performance

[Seaduced]

I am disappointed with the performance numbers of my boat.


In the spring, on a good day I could hit a top speed of 38-40 MPH. 


I know there are a ton of variables (ie. bottom growth) but this decline seems major.


I am suspecting that I slightly bent a propeller blade after running in shallow water, sandy bottom. (Paint is rubbed off very bottom skeg of outboard.)


I get no vibration however.


To my friends here with similar rigs...are these numbers consistent with your experience?


RPM


MPH


GPH


MPG


1000


4.5


0.8


6.1


1500


6.0


1.1


5.2


2000


7.0


1.9


4.0


2500


9.0


2.9


3.0


3000


14.0


3.8


3.6


3500


17.0


5.2


3.3


4000


22.0


7.3


3.0


4500


25.0


8.7


2.7


5000


28.0


11.3


2.4


5500


32.0


15.1


2.1


5600 (top)


33.0


16.4


2.0


 


 


 


 


Bennington 2275GCW - 2016


 


Yamaha F150XB, 25" sharft


 


 


Tritoon, with SPS


 


 


Mounting hole position #1


 


Powertech SS propeller, 15 x 15


 



400lb on board



 


 

 

[goldnrod24]

Two thoughts. Don't underestimate the negative effect of bottom growth on top speed. You acknowledge it's there, so I'd start there.


Second, I don't think you are propped right. You should have higher revs at WOT. 5600 seems too low to me. Isn't your max rpm more like 5800-6000? Have you tried a 13 or 14 pitch prop yet?

 

[1Blderbob]

You said that the boat achieved 38 before and it should do it again. I would tell you the same about marine growth and slime. Get it cleaned completely off your toons. I would start there first before trying the new prop route. And as for as a bent prop, are your edges dinged up? If they aren't, you don't have a bent prop. And if they have minor dings,that can cause a slight drop in speed also. With the combination of the two issues, 5mph drop is possible. Oh heck,just the growth can cause that much drop in speed. Let us know the outcome. Get the Yedi out and clean them toons.

 

[tcpip95]

Check your spark plugs to make sure they're not fouled. When was the last time you had your fuel injectors cleaned/serviced?

 

[Seaduced]

I guess I agree that marine growth could be the issue. That would certainly be the easiest and cheapest solution to the problem. I plan to pull the boat soon and clean the boat on the trailer with a powerwasher. I am not too sure how well I can clean the toons on the trailer however because of the bunks. I will give it a go however.


The boat only has 30 hours on it so far so I don't think fouled plugs could be an issue.


Thanks to all for your replies. I really appreciate it.


Jim

 

[Tooner]

We have the same motor on a 21 SLX, and while the slightly smaller and lighter boat meant our original top speed was 44 mph (by GPS), it has decreased as well. Our boat has been in a wet slip for over 9 months, and our top speed just yesterday was 38 mph. So, our speed decrease matches yours. I know for a fact we have a lot of fuzzy growth on ours, and it will soon be addressed. 


However, your top RPM does seem to be off. Ours if right around 5,900, and we are using a SS Yamaha SPS 15-M, 14 1/2.

 

[Seaduced]

I just had the local marina haul the boat for a powerwash.


There was surprisingly little marine growth on the pontoons.


Now the toons are spring clean.


Unfortunately the top speed increased only slightly....maybe 1 MPH at WOT.


I am left with engine issue or bad prop?