Fuel Tank F Up

wdirnbeck

Seaman Apprentice
Joined
Jun 5, 2022
Messages
41
Hey all, posting to see if my suspicions can be confirmed by anyone. I took my boat out yesterday expecting a nice day on the water after putting in a permanent fuel tank to replace my plastic portable. Unfortunately i got out of the no wake zone and put the hammer down just to find myself with low revs (2800 able to slowly climb to 3100) plowing through the water.

The only other thing I had done before going out besides replacing the fuel tank was adjusting the idle speed on muffs), I was trying to mess with that because I was having some issues staying idling (this issue was happening with the other fuel tank)

I’m sitting at my desk and had a revelation and am now wondering about how I rigged my new fuel tank. The fuel line from the tank to the engine is a 5/16” hose that I had been using with the previous plastic tank with no issue, however when I installed the new fuel tank I crammed that 5/16” hose onto a 1/2” barb with an 8AN fitting that screwed onto the fuel pickup. Is it possible that my issue is that the fuel pump on my 70hp Johnson just doesn’t have the power to pull gas through the large diameter fuel pickup in the tank? Do you guys have any ideas how I could rig a new pickup tube?
 

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Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,538
You motor will not have an issue puling fuel thru the larger dia fuel line. Replace the fuel line with the correct dia hose or get a proper reducer for the tank.

Normally idle mixture needs to be set on the water under load. Flusher devices do not provide the backpresure or load of a water setting. Be prepared to reset it when you are on the water under load.
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,145
I use 3/8 hose ...did you install a spin on filter? What type of hose did you use? Not the gray crap I hope.

Did you purge and out first?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
48,292
thats an AN fitting shown in the picture.
 

wdirnbeck

Seaman Apprentice
Joined
Jun 5, 2022
Messages
41
did you put the vent in?
Yes I ran a hose from the vent fitting which is just one of those AN fittings in my picture up to the vent port on the stern, I will check and make sure that is clear and that I didn’t accidentally install the hose on the rollover vent.
 
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