Dual fuel line to single line dilemma

[benj]

In the span of about 3 weeks, I’ve gone from having one outboard(68 JW-23M) to now having 3!(2nd purchase was an ebay deal on a JW-12)

Last Friday I acquired a 1959 5.5hp Evinrude Golden Jubilee Fisherman. The previous owner didn’t know that it used a dual line tank, and sold it to me with a 6 gallon single line tank. I’ve started to rebuild the carb, and since I have the intake plate off, that’s how I came to the dilemma:

Is it cheaper/easier to just switch to a single line set-up now, or somehow find a dual line tank that won’t break the bank?

The motor is in decent shape cosmetically, but nowhere close to showroom new. I plan on keeping all of the parts in case I or someone else restores it down the road.

Thanks in advance,

-Ben

[fleetwin]

Ben
The problem here is that there is nowhere to mount the fuel pump on this engine because there are no intake bypass covers, and no pulse port for the fuel pump. Do any of your other outboards use the two line tank? Sure, some sort of pump can be “rigged up”, but it is probably easier to just find a decent two line tank. Keep in mind that this engine requires the 16:1 mix because it has plain rod bearings. So, you can’t use the single line tank (with leaner mix for newer motors) anyway, you would need another single line tank with 16:1. Probably best to keep this engine on a two line tank to make sure you don’t accidentally use a single line tank with a leaner mix…..

[benj]

fleetwin

None of my other motors use the two line tank. I’d be inclined to run 16:1 on all the motors just for the sake of sanity if I do convert. I found this write up, which spawned the whole converting idea to begin with:
https://outboard-boat-motor-repair.com/Johnson%205.5%20HP%20Seahorse%20Outboard%20Boat%20Motor/Pressureized%20Fuel%20Tanks.htm

[Mumbles]

That’s an old wives tale about the tanks being dangerous and blowing up. Don’t believe a word of it.

‘A Warning About Pressurized Gasoline Fuel Tanks Used On Older OMC Motors
These motors use pressurized fuel tanks, known as Cruis-a-Day Tanks. Rather than sucking fuel from the tank, the dual line hose pumps air into the tank, pressurizing it to 4-7 PSI which forces fuel back to the motor. Basically, these pressurized tanks are an extremely dangerous fire or explosion danger. OMC finally stopped using these tanks after 1959..’

[fleetwin]

More blubbering by folks that don’t know that much…. We get really tired of hearing that the two line system is a fire/explosion hazard….There is a pressure relief valve in the tank to prevent excess pressure. And, like others here have noted, even single line tanks build up pressure in hot weather/direct sun light.
That fuel pump he is using requires and external pulse, which would come from the intake manifold. But, you would have to alter/change the intake manifold check valve set up in order to provide pressure and vacuum pulses. Again, there is no place to mount a fuel pump, you would have to fabricate something.
In the end, the decision is yours. I just don’t want your decision based on ridiculous claims about the pressure tank system being “dangerous/fire hazard”. On the other hand, all fuel systems can be dangerous if not properly maintained and ventilated….
I just think it will be easier and cheaper to find a decent two line tank, service it, and run the engine as it was set up originally.

[benj]

Don’t get me wrong, I’m not worried about a “perceived” explosion hazard. I trust that the system is just fine when it’s in order. I’m only thinking about converting to single line because I now have two single line tanks.

Basically, I’m trying to figure out which way is more economical.

I really appreciate the input from y’all!

[fleetwin]

Well, I guess that will depend on the cost of a decent fuel pump, vs the price of a decent used tank/hose. But again, converting the engine to single line tank will require alterations to your intake manifold and pressure tank check valve system inside the manifold… I suppose you could drill into the crankcase somewhere instead of messing with the manifold, but that is kind of risky….

[squierka39]

I’ve seen decent pressure tanks as cheap as $20. Start looking, you might find a bargain and save some time reengineering.

[jeff-register]

I ran many 2 line tanks. OMC & Mercury without any problems. The Pressure tank is much cleaner as the tank isn’t vented to outside air unless an over pressure happens. Look at the seams & bottom for issues.

[todd281]

I just bought two Johnsons a CD-12 and a HD-25 both for 40$ and the guy gave me a twin line tank with a 2 sets of hoses and extra fittings. Point is.. they are out there, you just have to find them.

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