Replacing old fuel line primer bulb style with fixed fuel tanks

[opc167]

I have a 1979 Johnson; 70EL79 that uses the primer bulb tanks. We want to use two fixed-mounted tanks that both tanks and would like to have them both running to the single fuel feed so it can pull at the same rate. We want one of the tanks to have a sending unit to the dash. By using both tanks feeding at the same rate, it allows the boat to maintain balance. do I need to use an external fuel pump in addition to what the motor is pumping and remove the primer?

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Put a Tee in the fuel lines coming from each tank and a single line going to the primer bulb and then the mtr. Just make sure both tanks draw the same amount of fuel or you might have probs.

 

[F_R]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Drawing from two tanks via a tee is possible, but not practical. It would be difficult if not impossible to draw equally from both at the same time. When one goes empty, the motor will suck air from that line instead of fuel from the other one. The result is you can run out of gas, even though you may have half a tankful in the other one. The proper way to do it is not with a tee but with a valve that allows you to select one tank or the other or both. Oh, and use two sending units. You can use a selector switch if you don't want two gauges.

 

[HighTrim]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Can you not run the tank across the width to equalize the weight load?

If the smart fellows above say it is fine, I believe them, just seems like a pain in the arse.

Also, you mention external fuel pump. I hope by that you dont mean a 12 volt pump.

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

F_R, I was going to suggest that but I had the feeling he didn't want to hear it. As you suggested the proper way is with the selector valve.

 

[nwcove]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

not sure if it applies to ob's, but in my many years on commercial inshore diesel boats, two tanks were used. the tanks were connected together with a line. (close to the bottom of both), effectively making two tanks act as one.

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

I guess that's okay if you fill both tanks the same when filling.

 

[nwcove]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

I guess that's okay if you fill both tanks the same when filling.

with that set up....both tanks fill at the same time.

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Do they have one fill for both tanks at the same time ?? Please explain ??

 

[64osby]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

O_O

Two tanks connected with a line that is low will fill at the same time, both at same level, as long as they are properly vented. Unless the boat is listing severely

Both sides of a liquid filled hose will be level or equal no matter how far a part they are.

 

[nwcove]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

^^^ what he said. but i did ask my father inlaw about how his dual tanks were set up on his fishing vessel. there are two fill caps, but he has never used the port side fill. the tanks are plumbed to work as one, or ,by opening/closing valves, either tank can be used on its own.

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Nwcove, read post # 3.

 

[nwcove]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Nwcove, read post # 3.

did read post #3, i was just answering your question in post#9, and adding info that i was told regarding post #3.

 

[F_R]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

O_O

Two tanks connected with a line that is low will fill at the same time, both at same level, as long as they are properly vented. Unless the boat is listing severely

Both sides of a liquid filled hose will be level or equal no matter how far a part they are.

I suppose that assumes the interconnecting line is large enough diameter to handle the fill flow rate.

 

[boobie]

Re: Replacing old fuel line primer bulb style with fixed fuel tanks

Good point F_R !!!