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57 Evinrude Fuel tank question

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333Fitter

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I have my dads 57 Evinrude with matching pressurized gas tank its leaking fuel from the vent hole
Does anyone hopefully in Mi repair these ?
 
Welcome. These really don't have a vent hole so the one on the cap is because of a bad cap gasket. Either that or there is a damage above the threads under the fill cap not allowing it to properly seal.
 
It is a PRESSURIZED tank !!----There is no vent when in use.-----When you are done for the day you back off the cap to release pressure on the fuel.-----Anb elegantly simple set-up.
 
Try shrinking your pictures sizes to under 1000k. These are valuable tanks you want to take good care of them.
 
A completely closed system free of any moisture or leak. You know there is a leak if it does not build pressure. Then you will not get fuel to your motor. I have dozens of motors still using this system which I use/sell regularly. Just keep the ethanol fuel away from them. Ethanol fuel was engineered to cause trouble and cause us to upgrade our things and force service and repairs in seasonal equipment, especially in Marine and where moisture is constantly present. At least half of my repairs are ethanol fuel related. It basically just belongs in modern fuel automobiles where consistent use is required. Modern diesel fuel as well, degrades 10 to 20x faster, typically within 6–12 months, primarily due to the addition of biodiesel (FAME) and the reduction of sulfur in Ultra-Low Sulfur Diesel (ULSD). These changes, combined with water accumulation from condensation, promote microbial growth, sludge formation, and oxidation, which clog filters and damage engines. Use sense and save your equipment.
 
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Those tanks can leak from the gasket between the top handle/pump assembly and the tank. try snugging up the mounting screws. As stated previously, no vent on this system by design. I too have a shop attic full of those tanks. You can still get the tank rebuild kits.
 
Thanks for the replys
Then what is this hole for ?
 

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I just went out to the shop and looked at two tanks, both have the hole in that spot. I took a piece of wire and inserted it and it is a blind hole about an inch in, not sure if the hole turns 90 degrees or not. My guess is that it may be an air bleed hole on the non pressurized side of the pump diaphragm to allow it to undulate during the priming function. If you have fuel coming out of it, the diaphragm may be bad. That's my educated guess. As Racer would say, "some may argue".
 
Thanks i rebuilt it last year cause it wouldnt hold press.
It did this when I 1st tried it this year.
Maybe it needs to prime itself or ??
 
I would take it apart again to gain understanding of why you have fuel coming out of that hole. There's a breech in the diaphragm or some other leak mechanism that's keeping it from priming correctly and loosing pressure.
 
Curiously, Are you trying to prime this while being connected to the engine? The fuel has to have somewhere to go... What 1957 Evinrude engine is it?
 
The primer on these tanks pumps fuel into the carburetor.-----When motor starts it quickly pumps air into the tank and keeps fuel flowing.----Cap on the tank must be tight to run.
 
I use a LITTLE non hardening aviation type permatex, if you invert the tank, nothing should leak on your workbench. NOTHING!
 
Here You go, brother.
It's hard to believe but I have many many of these tanks that are still original and have never been rebuilt that work perfectly absolutely perfectly beautiful engineering. Their worst enemy is ethanol fuel.
 

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Ha, I'm laying low after heart surgery, so I've been joining the forum. Returning from Mayo Rochester home today, So I will not have much forum time after this..Lots of outboard repairs to catch up on, brother....we certainly need you and ageless Racer on these older motors especially. Thanks.
 
timguy said:
Ha, I'm laying low after heart surgery, so I've been joining the forum. Returning from Mayo Rochester home today, So I will not have much forum time after this..Lots of outboard repairs to catch up on, brother....we certainly need you and ageless Racer on these older motors especially.
Click to expand...
 
Godspeed on your heart surgery recovery. I've always appreciated your knowledge, generosity, kind words, and your balance. You speak from experience without being condescending. You are our forum jewel.. Now get back to twisting wrenches!
 
Thanks. You helped pick me up, Fitz. I have worked hard to help this forum. Words of support can only bring progress.
 
Ok i took tank unit apart again now it wont even pump or build press so i set it aside found another which seems to work.
Looks like ill have to pay someone to rebuild it.
 
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