Old Pressure Fuel tank "Pops"

[tonynoriega]

So I just about have this figured out...just a few more nuggets and I should be good to go.

I am realizing that during operation, a bit of fuel is coming out of the metal push button primer on the tank.

From most of my research, it seems I need to get back in there and adjust the diaphragm gasket I just repaired.

And also replace the bent push button stem.

Secondly, I notice that after I turn off the motor, and release pressure on the tanks it "pops", like the tank is expanding back to its natural form.

Is that normal?

 

[Jim]

Bump!

Anyone?

 

[tonynoriega]

It seems to be one of the side walls... like the pressure makes it cave in a bit, then when pressure is released, it pops back out.

 

[Captain Ahab]

No very familiar with type of tank - I take it you need to pump it up or something to get the fuel to the carb?

Does it have a vent?

 

[BrazosDon]

Everything has to be just right for the old tank to work otherwise it is like a bomb it could/will go off at any time. Here is a cure for that if you don't know about it. I have a '57 Evinrude 18 hp that has that system on it. Mine I just got from my motor guy and everything is OK.


Converting the Old OMC Dual Fuel Line to a single line

https://www.leeroysramblings.com/Converting_dual_fuel_line.htm

https://outboard-boat-motor-repair.com/Johnson/Pressureized%20Fuel%20Tanks.htm

 

[BrazosDon]

Capt. Ahab, do you think that might help that young man.

 

[tonynoriega]

It is a typical 50's duel line fuel tank. Evinrude.

I do not know if it has a vent or not... it does rely on being totally pressurized, I believe.

There is a small hole on the tank cap, but am unsure of the purpose of that.

Captain Ahab » Today, 19:03[/url]"]No very familiar with type of tank - I take it you need to pump it up or something to get the fuel to the carb?

Does it have a vent?

 

[BrazosDon]

You only vent it when you are not using it. Pressurize it when you are running it. Don't leave it in the sun too long. Read the articles and get familiar with the motor and the gas tank. The more you know about it the safer you will be. Do you know what the fuel to oil ratio is? 24/1

 

[Captain Ahab]

Thanks BrazosDon! Glad you have knowledge here!


tonynoriega - Read the links

 

[lckstckn2smknbrls]

Maybe your thinking about it the wrong way. The pop you hear could be the release of pressure allowing the tank returning to it's normal shape.

 

[tonynoriega]

Correct, that is exactly what I am thinking.

And that is my question... Should that even happen?

I am running 50/1 ratio oil fuel per my mechanic at the shop...who I trust with no doubt.

I have read all I can on these motors and tanks and am fairly confident in the overall relationship between the two.

Just not an expert my any means.

lckstckn2smknbrls » Today, 10:26[/url]"]Maybe your thinking about it the wrong way. The pop you hear could be the release of pressure allowing the tank returning to it's normal shape.

 

[SumDumGuy]

Your mechanic may know something about "modern" motors, but the oil:gas ratio he told you to use for this motor is wrong.
you should be running somewhere around 24:1 for that motor.

 

[lckstckn2smknbrls]

SumDumGuy » Sat Apr 26, 2014 5:45 pm[/url]"]Your mechanic may know something about "modern" motors, but the oil:gas ratio he told you to use for this motor is wrong.
you should be running somewhere around 24:1 for that motor.

+1

 

[Mel Taylor]

tonynoriega » 26 Apr 2014, 14:46[/url]"] I am running 50/1 ratio oil fuel per my mechanic at the shop...who I trust with no doubt.

You may trust your mechanic, but I wouldn't. At least when it comes to fuel/oil ratios. 24 to 1 is the correct ratio for that motor unless it was manufactured after 1964. You can check it out here:
https://www.evinrudenation.com/owner-zone/top-20-faqs-about-outboards/

 

[lovedr79]

Definitley 24:1 old motors need lots of oil. Haven't seen one of those setups in quote awhile