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Uprate the outboard on J70: Any experience please?

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My 3.5 hp two stroke does not  instill confidence and is not very environmentally friendly.  I would like to  upgrade to a 4hp 4 stroke. But it weighs 26kg. Nearly twice as heavy as the 2 stroke  Certainly I expect to have modify/strengthen the bracket. Can the transom take the weight? Please can anyone share any experience of fitting a 4 stroke 4hp to a J70?

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The 4-5-6 from all of the brands are the same base unit, hence weigh the same.   The Mercury-Tohatsu-Nissan 4-5-6 come in at 57-59lbs.  I used a 3.5hp 4-stroke on my 31' 4700lbs'ish boat, more than ample for a J/70.   Plenty of grunt and 42lbs, sips fuel at WOT.     The surprise is the newer Suzuki, my next purchase, where you can get a 6hp for 53lbs!

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They all suck!  Our Suzuki was constantly hydro locked.  I can count on 1 hand the number of times it started right up in the 3 years we had the boat.  We stored it the right way, but it still ended up with oil in the cylinder.

MS

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Thank you for your comments . I am confident that a 4hp will have the power. (Sea can get pretry gnarly here quickly).What I dont want to do  is snap the transom off during one of those bouncy seas.... 

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For gasoline powered, the little honda 2.3 is hard to beat.

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Its the extra long shaft that you need, not the extra power. Unfortunately only Tohatsu/Mercury seem to make one and it weighs about 60lb.

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If you use biodegradable oil, strokers will get the job done.  Look for thrust, not h.p.  By following the manual that comes with the outboard, you will be amazed what 1950s technology can do, and the smoke makes everyone hungry for pizza.

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Thanks I just need to know of the J70 transom is strong enough for a 26 kg deadweight hanging off the back 

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The Leur propane motors are pretty trouble free, the problem is you never know how full the coleman propane canisters are.

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On 4/7/2020 at 1:13 PM, jamesmalcolm said:

The Leur propane motors are pretty trouble free, the problem is you never know how full the coleman propane canisters are.

Just weigh them....

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You will be the only person with a 4-6HP (heavy) on the J/70.   Everyone else gets by with a lightweight motor, no?   If the 3.5HP is enough to push my 4500lbs+ 31' boat to 6k it is certainly enough for a little J/70.    

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On 4/9/2020 at 11:53 AM, solosailor said:

You will be the only person with a 4-6HP (heavy) on the J/70.   Everyone else gets by with a lightweight motor, no?   If the 3.5HP is enough to push my 4500lbs+ 31' boat to 6k it is certainly enough for a little J/70.    

Are you sure the decimal place is supposed to be there in 3.5? I need whatever version of seafoam you have.

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On 4/7/2020 at 4:13 PM, jamesmalcolm said:

The Leur propane motors are pretty trouble free, the problem is you never know how full the coleman propane canisters are.

Are you smoking crack? First and only outboard I've ever had corrode to a point of being totally unusable...on the morning of a race no less!

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1 hour ago, jackolantern said:

Are you smoking crack? First and only outboard I've ever had corrode to a point of being totally unusable...on the morning of a race no less!

I'm on crack? All you have to do is spray it with fresh water and oil it. My team's has been through the ringer and it's still chugging along. Besides, everything works fine 'till race day. It's the law of the sea. You never miss that one specific thing until it's too late to go back to the dock.

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More than 5 days without a single post on J/Boat Forum is another sign of the economic depression.

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Thank you all for your comments. Looks like I will have to stick with my rattly 2stroke . 

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Show your stroker some love.  They will run forever if you use fresh gas[smell it] and good oil.  Go to Saving old seagulls and check out their tips and classic runners.  Most of the other strokers are Tohatsu based, and have to have very clean gas.  Good luck with your mosquito fogger.

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