1958 johnson 7.5 fuel pump conversion/location

HighTrim

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Re: 1958 johnson 7.5 fuel pump conversion/location

Your line destinations are right. Let us know how that BS Pump works at WOT, I have done them for others and tested in my tank, but have not actually ran one on a boat yet.

Zeph, I have used alot of the Mikunis for the QDs and up, but have not found a suitable mount for them on the 7.5s and 5.5s. I have seen the zip tie method, but like NWCove, prefer a neater/cleaner look. If anyone has pics of one mounted post it, would love ideas.
 

HighTrim

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Re: 1958 johnson 7.5 fuel pump conversion/location

Sorry, but cant figure out why you have to run the outlet line from the pump around the powerhead?
 

nwcove

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Re: 1958 johnson 7.5 fuel pump conversion/location

Sorry, but cant figure out why you have to run the outlet line from the pump around the powerhead?

not 100% sure i have to route it that way, just from eyeballing it , it looks like the line may get kinked if i take the short path to the carb, but i will try that way first. ( my pump is mounted out about 3/8" from the powerhead)
i now have a new issue with a fuel tank i picked up for it!! will start another thread on that tho.
 

nwcove

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Re: 1958 johnson 7.5 fuel pump conversion/location

Your line destinations are right. Let us know how that BS Pump works at WOT, I have done them for others and tested in my tank, but have not actually ran one on a boat yet.

Zeph, I have used alot of the Mikunis for the QDs and up, but have not found a suitable mount for them on the 7.5s and 5.5s. I have seen the zip tie method, but like NWCove, prefer a neater/cleaner look. If anyone has pics of one mounted post it, would love ideas.

if i remember right , the pump is rated to 14 liters/hr, so it should feed enough fuel, but i am curious about how well the pump will be able to lift fuel. i did use 1/8" id ridged chemical feed line for the pulse, and it is the same as the id for the pump nipples and the brass fitting, hope that does what i think it will do, and create a snappier pulse than a larger id line.
 

HighTrim

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10,486
Re: 1958 johnson 7.5 fuel pump conversion/location

Ive always been ok with the lower loop, as long as I mount on the top bypass cover of course. Looks like your height should be fine to run it direct to the carb.

I only use 3/16" line, as I do a wide variety of motors and I buy it in 100' rolls, but let us know how the 1/8" does with the pump.

Good luck.
 

nwcove

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Re: 1958 johnson 7.5 fuel pump conversion/location

http://www.youtube.com/watch?v=icOMZ9OvaLA&feature=youtu.be

well here it lives! no carb rebuild yet, or impeller, but it seems to run well and is pumping good water. it does need a shift lever o-ring , which will get replaced when i pull the powerhead for the pump replacement. but the conversion to fuel pump seems to work well in the tank. (fuel was mixed at 10:1 for the first start for the motor in who knows how long.....two smoker!! lol)
 

Daviet

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Sep 24, 2008
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8,958
Re: 1958 johnson 7.5 fuel pump conversion/location

Man, you gota love the way those old engines run, good job. I hope it gives you many years of service.
 

kfa4303

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Sep 17, 2010
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Re: 1958 johnson 7.5 fuel pump conversion/location

awesome! I LOVE the look of those '58s. Happy vroom-vrooming!
 
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