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Thread: 25 merc jet enough for 16x40 Jon?

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    Talking 25 merc jet enough for 16x40 Jon?

    Hey guys,Just curious if anyone has any input on a 25 mercury jet on a Jon boat. Just looking to have a little su boat and maybe 20 mile, would this be an okay set up for 2 guys or the wife daughter dog and myself? Thanks for any input, and I would gladly go bigger if you are opening your check book to help out.

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    Supporting Member Old John's Avatar
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    I have serious doubts that that 25 jet could get up on step with more than a small person in the boat...

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    Dont think it would work wAY UNDER POWER

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    Ditto, and not gonna open up my checkbook to help, lol.
    Thats funny!
    Tennessee

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    Hmm, no need for a 1:1 power/weight ratio: http://www.youtube.com/watch?v=3GEkMb3fcnQ Although more power is always better.

    Take a look at my homebuilt "underpowered" jet boat in some of the videos here: http://vimeo.com/user6002842/videos slow, but still capable.

    That said, I dounbt a 25/17 could handle 3 + the dog, better off finding a nice used 50/35.

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    I have a 18x48 riveted jon with 60/40 2 stroke jet. runs good. can do 32 mph down and 27 up on big su. 25 out the jet might work running light but i think you would be happy with a little more hp.

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    Member chico99645's Avatar
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    My son had a 14 foot flat bottom jon boat with a 25 hp merc engine. He had to run wide open all the time on the lil sue with 2 people in the boat with light gear just to get somewhere and not in a hurry to get there. 16' would be way under powered IMO.

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    Quote Originally Posted by chico99645 View Post
    My son had a 14 foot flat bottom jon boat with a 25 hp merc engine. He had to run wide open all the time on the lil sue with 2 people in the boat with light gear just to get somewhere and not in a hurry to get there. 16' would be way under powered IMO.
    In an answer to my own post, it works. A little boggish with the mentioned load, but alone in flys. It is 25 at the pump and does 22 up river with the 350 I had in it. I know after reading most post on here that probably isn't great, but sure seems like a good little su boat and we had a great weekend. I think a 14x48 would be perfect for this motor, and after running up several miles on the little su, a tunnel wouldn't hurt. Of course an Alaskan xl wouldn't hurt either, but my wallet would. Thanks for all the imput, even though I didn't really listen, I guess.

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    Quote Originally Posted by Don_h View Post
    In an answer to my own post, it works. A little boggish with the mentioned load, but alone in flys. It is 25 at the pump and does 22 up river with the 350 I had in it. I know after reading most post on here that probably isn't great, but sure seems like a good little su boat and we had a great weekend. I think a 14x48 would be perfect for this motor, and after running up several miles on the little su, a tunnel wouldn't hurt. Of course an Alaskan xl wouldn't hurt either, but my wallet would. Thanks for all the imput, even though I didn't really listen, I guess.
    I have a factor 20 hp Johnson Jet (20 hp at the pump) on a 14 footer and it will plane 3 guys ok. It is really good with only 2 and quickly jumps on step. It isn't going to win any races, but it does surprisingly well. I personally think that a lightly loaded 16 footer would do better.

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    I have a 25hp 2-stroke Yamaha powerhead with a jet. It runs my G3 18' x 52" boat just fine. Better than fine. The boat can carry three adults and day gear easily. Properly balanced it carries four with gear but it does take longer to get on step and runs a little slower. All this underpowered speculation is nonsense. An 18' boat will always plane better/easier than a 14' or 16' carrying an equally proportioned load.

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    Quote Originally Posted by Mr. Pid View Post
    I have a 25hp 2-stroke Yamaha powerhead with a jet. It runs my G3 18' x 52" boat just fine. Better than fine. The boat can carry three adults and day gear easily. Properly balanced it carries four with gear but it does take longer to get on step and runs a little slower. All this underpowered speculation is nonsense. An 18' boat will always plane better/easier than a 14' or 16' carrying an equally proportioned load.
    Are you serious? 25hp 2-stroke with that big of a boat? If so, your telling me that my 25hp 2-stroke Merc would be okay jetted on my Seaark 1448 riveted at 245lbs?

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    Quote Originally Posted by Tbradley View Post
    Are you serious? 25hp 2-stroke with that big of a boat? If so, your telling me that my 25hp 2-stroke Merc would be okay jetted on my Seaark 1448 riveted at 245lbs?
    If your transom will take that much it will be just fine. My 14 foot boat has a 20 hp jet on the back of it and it does fine. The 20 hp johnson jets do have a 30 hp powerhead though from what I have been told. But, on my 14 foot hewescraft, which is a light narrow boat, it will slug along in the the high teens to low 20s with 2 big guys on the Little Su. With just me, some fuel, and fishing stuff, I can run at half throttle and go about 15-20 mph. I have done three before, and it is still dooable, just not optimal....

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    Well the motor I have is the 4 stroke with the bigger powerhead. 25 seems great with a small load but the more I add it is sure noticeable. I have been curios to know if it would preform better with a 48 or larger bottom. All together though I am pretty pleased. No waterskiing, but for dinking around it's great.

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    Quote Originally Posted by Tbradley View Post
    Are you serious? 25hp 2-stroke with that big of a boat? If so, your telling me that my 25hp 2-stroke Merc would be okay jetted on my Seaark 1448 riveted at 245lbs?
    Keep in mind my G3 hull is pretty light but it gets along fine. I drove it today with me, my wife, a 70# dog, and 3 tupperware totes full of stuff. No problem. My wife prefers it to our bigger/heavier/faster boat.

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