Fuel line not holding suction...70 hp

U

Urafemac

New member
1984 70 hp Johnson, Original owner.

I have had all sorts of issues with this motor holding vacuum on the fuel lines. I find myself replacing the fuel adapters every year because the o-rings crack every season. Now, on to the problem...it holds suction while running but once the engine stops it loses pressure and I have to pump it back up to get gas in the line. I have installed new clamps, new fuel lines and a new primer bulb. I Tightened the fuel clamps on all the connections till my fingers bleed. Also, I made sure the carb assembly connections were tight.

Is there something I am missing here?
 
Urafemac":3ml27ge4 said:
1984 70 hp Johnson, Original owner.

I have had all sorts of issues with this motor holding vacuum on the fuel lines. I find myself replacing the fuel adapters every year because the o-rings crack every season. Now, on to the problem...it holds suction while running but once the engine stops it loses pressure and I have to pump it back up to get gas in the line. I have installed new clamps, new fuel lines and a new primer bulb. I Tightened the fuel clamps on all the connections till my fingers bleed. Also, I made sure the carb assembly connections were tight.

Is there something I am missing here?
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How old is the fuel line itself? I assume it's been replaced a few times. BTW - same outboard since 1984 - I know plenty of marriages that haven't lasted that long!
 
Sometimes fuel lines are cut lengthwise to remove them from a barbed fitting. This can result in damage to the brass or plastic barb. I have seen leaks from this cut "line" despite being double clamped.

Another thing to check - there is a marine fuel line which has a liner to prevent any permeation. It requires a different size/type of barb and if put on a regular barb will leak.
 
'84 was the first year for VRO

You mix your gas though, right?

My 140 that year I converted over.

And of course you have the bulb pointed in the correct direction, i'm sure
 
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