Pressurization on old OMC Johnson/Evinrude Fuel Cans

[CaneCutter79]

I'm questioning how these old cans work with pressurization and should they be vented when not connected to the fuel line? I only have one fuel line and I swap tanks when needed.

I have some older 1979 6gal fuel cans and a couple of years ago, each can popped a pin hole in the bottom of each tank. One single hole, about the same location. Neither were from rust. I cleaned out the tanks and no rust was found in the bottom of the cans (I used a flashlight and looked all around the can as best I could). I sealed the holes with JB Weld and it worked. I've been using the cans this way ever since then.

How did the pin holes get there? The cans were in my boat and on hot day, the pressure increased so much due to heat/expansion that tanks swelled some and the pins holes relieved the pressure. Gas went all over the interior of my boat and leaked out the plug hole. I imediately took the boat to a carwash and washed out the fuel as best I could to prevent a fire and further deterioration of the fiberglass.

Both tanks were disconnected from the motor when this occured.

According to my repair manual for my outboard, both tanks are sealed until the o-rings are released when the tank is connected to the fuel line with the OMC fuel connections. Once connected, the tank is allowed to vent. I drilled a small hole into the gas cap on each tank (completely through) to allow ventilation and to prevent this from happening again. I have not had any issues since then and I thought I solved my problem. Now I'm second guessing this decision. I don't want it to hurt the motor if pressuization is needed for the fuel pump or something.

QUESTION:[/B]Now that you know the history of the problem, that I have a small pin-hole in my gas caps, etc......

Should I replace the gas caps? Could this cause the fuel pump to not work correctly? I have a 1979 Evinrude, 85hp Mod: 859995.

 

[boobie]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

The only time those tanks were vented was when the fuel line was hooked up. And yes they will build pressure with the fuel line disconnected. If you have holes in the caps now you should be okay, but keep them out of the rain. You might also find some caps that will fit that had a screw type vent that you could open and close manually. The tank has to be vented for your fuel pump to work properly.

 

[CaneCutter79]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

Tanks are under a hatch lid so no worries about rain or water getting in. Tiny pin holes anyway. Just enough for air. Maybe 1/64th if an inch?

Thanks!

 

[boobie]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

As long as your primer bulb doesn't go flat on you when you're running you're okay.

 

[tazrig]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

It sounds like you had a couple of defective tanks or at 33 years old the metal just fatigued. In 40 years of boating I've never heard of that happening. However, leaving open holes of any size in your 6 gallon tanks (left in an enclosed non ventilated area like your boat or garage or basement etc is extremely dangerous!!! Gas vapors are heavier than air. When your tanks expand and push out the vapors through the holes you just made the vapors will settle to the lowest surface they can find such as your deck. You won't smell the gas because the vapors will be at ankle height. All you need is one spark and BOOM!!! Thats why you hear about boats blowing up at gas docks. the vapors sink to the bottom of the bilge and the blower either isn't run or run long enough to suck out all the fumes. The boat is started, there's a spark, the vapors ignite followed by all the fuel. Your tanks are vented so you don't develop a vacuum in your gas line. In other words they are vented not to protect you from getting too much pressure, but from too little. You should go out and at least get 2 new caps and I would strongly suggest just getting 2 new tanks. I was a Police EMT for 10 years and saw a lot of bad accidents related to mishandling gas. Trust me... for the price of a couple of tanks, you really don't want to become a statistic or worse be responsible for harm coming to a loved one.

 

[F_R]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

tazrig brings up some valid points to think about. Those tanks were designed to not emit fuel or vapors and defective ones should be replaced or replaced. Tanks and hoses built today are even more strict, allowing virtually zero emissions, even permeation through the hoses. As a result, they have become extremely expensive. OK, having said that I say it wouldn't be harmful to have a 1/64" vent hole in a tank that is stored in an open boat outdoors. Anyway, portable tanks stored in enclosed, unventilated spaces in a boat are illegal, aren't they? Somewhere we have lost touch with reality. Just my 2c, not meaning to get too political.

BTW, my uncle's garage burned to the ground one night when his car caught fire. Makes one wonder about garages attached to the house, doesn't it? (Mine is).

 

[tazrig]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

In an open boat while underway and a strong wind blowing I agree with you it's perfectly safe. What I am talking about is the boat sitting for a period of time at the dock, driveway or on a rack somewhere and the initial start up or the bilge pump with a frayed wire coming on or any kind of a spark while the boat isn't moving. When you have had to see and treat people with large chunks of skin and flesh missing or peeling off of their bodies because of gasoline fumes that ignited I would say that is dealing with reality. Not dealing with reality is exposing yourself needlessly to an unsafe situation and thinking an accident can't happen to you. IMHO

 

[boobie]

Re: Pressurization on old OMC Johnson/Evinrude Fuel Cans

On those older tanks if you left the fuel lines hooked up to the tank when sitting, they'd still be vented to the atmosphere. Correct ?? How many people pull the fuel line off of the tank when done boating ??