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Full tank of gas 4.5 hours

Jando

Jando

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Stevens Point, WI
Hey all, got my new boat in the water this weekend.  It is a 22ft SSRX pontoon with lifting strikes.  It is powered with a Merc 115 command thrust.  I'm also running an OEM 3 blade stainless 15 pitch x 15 diameter that Bennington recommended.


i went through a full tank of gas in 4.5 hours of use.  Most 4000 rpm or less.  Dealer said I could take it up over 4000 after 2 hours but only for a few hundred yards at a time.


My confusion.....the gas use....everyone says that seems high.
 
Should be ~3-4 gph at 3500-4000rpm, 10 gph at 6000rpm, full throttle.
 
Congratulations on the new arrival! Yes, that seems high but how many gallon tank do you have? With the bus I have, I'm not expecting great gas mileage but I think mine was pretty low considering that I was not going a constant speed during the break-in period and going full throttle every ten minutes.
 
Remember, fuel gauges on boats are notoriously inaccurate. How do your fill up amounts square with the size of the tank? Do you have SPS? That center tube-mounted tanks looks difficult to engineer an accurate float for it.


Also, a 15 pitch prop seems like too much for a 115 or do you have an Express Tube? I went to a 15 pitch after my Express installation.
 
goldnrod24 said:
Remember, fuel gauges on boats are notoriously inaccurate. How do your fill up amounts square with the size of the tank? Do you have SPS? That center tube-mounted tanks looks difficult to engineer an accurate float for it.


Also, a 15 pitch prop seems like too much for a 115 or do you have an Express Tube? I went to a 15 pitch after my Express installation.
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Dealer didn't fill it, only had a small amount for testing in their bay.  I put in a little over 31 gallons and gauge was reading 1/8 tank after the time I mentioned.


No SPS or express tube.  Based on my reading here I told dealer I thought prop pitch was too much but he said that is what factory rep told them to use.
 
Michiman said:
Congratulations on the new arrival! Yes, that seems high but how many gallon tank do you have? With the bus I have, I'm not expecting great gas mileage but I think mine was pretty low considering that I was not going a constant speed during the break-in period and going full throttle every ten minutes.
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Thanks, will get more pics posted soon.  I'm guessing it's 32-34 gallons
 
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Jando said:
Dealer didn't fill it, only had a small amount for testing in their bay.  I put in a little over 31 gallons and gauge was reading 1/8 tank after the time I mentioned.


No SPS or express tube.  Based on my reading here I told dealer I thought prop pitch was too much but he said that is what factory rep told them to use.
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Every boat is different. I think a 13 pitch prop is what you need. Also, a SS prop is overkill on a 115. Tell your dealer that once you are out of the break in period, you need some props to test. My money is on an aluminum 13 pitch prop.
 
Jando said:
Hey all, got my new boat in the water this weekend.  It is a 22ft SSRX pontoon with lifting strikes.  It is powered with a Merc 115 command thrust.  I'm also running an OEM 3 blade stainless 15 pitch x 15 diameter that Bennington recommended.


i went through a full tank of gas in 4.5 hours of use.  Most 4000 rpm or less.  Dealer said I could take it up over 4000 after 2 hours but only for a few hundred yards at a time.


My confusion.....the gas use....everyone says that seems high.
Click to expand...

Hi Jando, I think that is way to much gas used for just 4.5 hrs.


I have basically the same boat as yours. 2016 ssrx 115 mercury CT. We have been out last fri, sat, and sunday on the Mississippi river, I started with full tank and currently have 6hrs and fuel gauge shows slightly over 1/4 full. we didn't due any skiing or tubing but have up to 5 to 7 adults. and probably included 1 hour of no wake <10mph speed, 5-7 min of WOT but mostly 3500 to 5000 RPM during break-in period. Running the same prop also 15.25 by 15P  


Just my old school of thought, but could the sending unit be reading incorrectly may have to top it off and see how much it takes.
 
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goldnrod24 said:
Every boat is different. I think a 13 pitch prop is what you need. Also, a SS prop is overkill on a 115. Tell your dealer that once you are out of the break in period, you need some props to test. My money is on an aluminum 13 pitch prop.
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Does SS hurt fuel efficiency or is it just not worth paying for?
 
I believe that the prop bennington is recommending for our boats is the correct one. It will be the same diameter and pitch as the 150's use. Because the lower gear ratio is 2.38-1 


I was able to reach 32 mph @5500 rps with 4 adults an 3 kids on rougher waters. With wife and I alone we were at 36 mph and 6000 rpm witch i think is the recommended upper rpm range of 55-6000. 
 
Our dealer has many boats with 115s and all have aluminum 13 pitch.


Aluminum is more forgiving when you hit bottom or a rock. A SS prop will probably take out the prop shaft too.


The 150s flex the aluminum too much, hence the need for the SS prop. The 115s will not, regardless of gear ratio.
 
I currently have a 2006 2250 GL with a 115 Merc and your gas consumption seems high.  Congrats on the new boat!  
 
goldnrod24 said:
Our dealer has many boats with 115s and all have aluminum 13 pitch.


Aluminum is more forgiving when you hit bottom or a rock. A SS prop will probably take out the prop shaft too.


The 150s flex the aluminum too much, hence the need for the SS prop. The 115s will not, regardless of gear ratio.
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I believe they ship with that 13 pitch.  I did ask for a stainless exchange and when they put the 15 on I was surprised.  I think I'm going to try a 13x14.5 aluminum and see how that does.  $115 all in  to see and always good to have an extra.  
 
Seems very high to me. I went out 6 hours on Sunday (WOT 50% of the time, pulled wakeboarders, tubes...) wasted maybe 1/4 tank.
 
Stock tank is 21.4 


22SSRX


SPEC/CAPACITY


US


LOA:


22' 8"


Pontoon Length:


21' 4"


Deck Length:


21' 6"


Beam:


8' 6"


Pontoon Diameter:


25"


Engine Configuration:


Single Outboard


Fuel Type:


Gasoline


Fuel Capacity:


21.4
 
Jack M said:
Stock tank is 21.4 


22SSRX


SPEC/CAPACITY


US


LOA:


22' 8"


Pontoon Length:


21' 4"


Deck Length:


21' 6"


Beam:


8' 6"


Pontoon Diameter:


25"


Engine Configuration:


Single Outboard


Fuel Type:


Gasoline


Fuel Capacity:


21.4
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Could have sworn I put 30 gallons in.  Maybe I was just so damn excited to have gotten the boat I got it mixed up! :)   
 
Jando said:
I believe they ship with that 13 pitch.  I did ask for a stainless exchange and when they put the 15 on I was surprised.  I think I'm going to try a 13x14.5 aluminum and see how that does.  $115 all in  to see and always good to have an extra.  
Click to expand...

I know where you are at on the river Jando....  be mindful to have a spare prop with you if you run aluminum.... if you hit a rock or submersed log you may need to swap it out on the water.  While my current motor is larger HP suggesting a stainless, I'd probably still run a stainless on your motor due to river section your on. 


When I had my prior boat and ran aluminum in those river sections... I had 3 props for the boat.  1 on the motor, 1 as spare in the boat, and 1 in the shop being rebuilt.


Hope to see you out there sometime!!! 
 
Landscaper2009 said:
Seems very high to me. I went out 6 hours on Sunday (WOT 50% of the time, pulled wakeboarders, tubes...) wasted maybe 1/4 tank.
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WOT for 3 hours not including 3 hours less than that and only burned 1/4 tank of gas?  I think you need to contact Merc and tell them something is wrong with your engine, it makes fuel :)
 
Scott1 said:
WOT for 3 hours not including 3 hours less than that and only burned 1/4 tank of gas?  I think you need to contact Merc and tell them something is wrong with your engine, it makes fuel :)
Click to expand...

No Merc here. Evinrude E-Tec 250 2-stroke direct injected.
 
Landscaper2009 said:
No Merc here. Evinrude E-Tec 250 2-stroke direct injected.
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Impressive! We really didn't have much of a choice with respect to engine manufacturer through our dealer. 
 
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