pressure tank vs fuel pump

[coolguy147]

im stuck at deciding whether to change my pressure tank to a fuel pump

is there easier starting or better performance? or anything else

 

[tashasdaddy]

Re: pressure tank vs fuel pump

it is just a different way of delivering fuel. safety there is no difference. depending on the motor, it will cost in the neighborhood of $100-125 to change. if you have a good pressure tank, stay with it. there are also rebuild kits for the pressure tank.

 

[coolguy147]

Re: pressure tank vs fuel pump

i know but r there any advantages or disadvantages with haveing a fuel pump or pressure tank?

 

[wbeaton]

Re: pressure tank vs fuel pump

Only advantage of a single line over a dual line system is that you can get a replacement tank/line for a single line system just about anywhere. I'd stick with the original dual line.

 

[coolguy147]

Re: pressure tank vs fuel pump

i would switch ovr except the fact that it cost a lot of money and im bound ot make a costly mistake soemwhere. really the fact y i wanna change is just cause its a single line and and less thing to worry about u know lol.

ya my tank is fine except for maybe some rust o rings needing replaceing and sometime later on fuel air line but other then that my decals and such on the tank r gone but it works fine but i think my fuel gauge just suddenly stopped working its like on zero.

 

[tashasdaddy]

Re: pressure tank vs fuel pump

the cork either came off, or is saturated with fuel. just open the cap and look in. what motor do you have??

 

[tmcalavy]

Re: pressure tank vs fuel pump

Another advantage is being able to use one tank for all your motors...that's why I converted my late 50's OMC's to fuel pumps. I can use either the 6 or 3 gallon tank with anything I own. Cost me less an $75 to convert my Johnson FD-11 and less than $50 to convert the E-Rude Big Twin...using a Mikuni fuel pump.

 

[Chinewalker]

Re: pressure tank vs fuel pump

One disadvantage to using a single line tank on a motor originally set up for dual line is that you run the risk of mixing up the fuel ratios if you run other motors. All dual line motors need a 24:1 mix, while most (but not all) single line motors run a 50:1 mix. Inadvertantly grab the wrong tank and you could be in trouble...
- Scott

 

[coolguy147]

Re: pressure tank vs fuel pump

i agree with walker about the mistake but it can easily be overcomed with a big sharpy writing 24:1 or 50:1

i think my cork is probably saturated but idk ya i would change but ill stick to the pressure tank for now

 

[coolguy147]

Re: pressure tank vs fuel pump

oh i have a 1959 evinrude sportwin 10hp that i been working on by the way

 

[Willyclay]

Re: pressure tank vs fuel pump

Unless you are dead-set on maintaining the original condition of the motor, then you should be concerned about SAFETY! Fuel under pressure is inherently more dangerous than using a suction, single-line system. As long as the hoses are in good shape, everything is fine with either system. If the hose cracks or splits, then the differences are significant.

A leak in a single-line hose usually results in air being sucked into the fuel pump and carb which only produces poor engine performance. A leak in the fuel/pressure side of a two-line system results in fuel being sprayed under pressure into places it should not be in your boat. BTDT. Spent a long afternoon in the ICW south of Savannah, GA with a bilge full of gasoline due to a leaking two-line system. Nobody got hurt, no fire and the boat didn't blow-up but to this day I don't know why not. We were very lucky.

Be safe and good luck!

 

[coolguy147]

Re: pressure tank vs fuel pump

lol ya i tank great words of wisdom from u man that is really true about those things. no im not worried about keeping oringinal condition to my motor. i mean if u can make it go 60mph rather then 5mph i mean go ahead lol.

but ya ill convert it sometime when i get mroe exp but i think my hoses r fine for now and evyrtime i start it i check all the hoses and evrything basically i open the hood evrytime and look at evrything lol

 

[lbentz]

Re: pressure tank vs fuel pump

It's easy enough to buy a fuel pump and bypass cover for a 1962 Sportwin and it would still look original. As far as safety goes, there was a very good reason why twin line tanks were discontinued in 1958 and a good one was posted by Willyclay here. Twin line tanks create a "pressurized bomb" in your boat and if a spark off of someone's ciggarette should fly towards the back....

BOOM

There goes your day

Be safe and happy boating.

 

[coolguy147]

Re: pressure tank vs fuel pump

ya was i reading some where it pressurerizes to like 4-7 pounds of pressure and there was a caution. well ya i do it after evrything think else is fixed.

 

[wbeaton]

Re: pressure tank vs fuel pump

Pressure tanks are no more dangerous than single line tanks. I have tanks that have been in service over 50 years and they are still fine. I agree a fuel pump is a better system, but the pressure tank isn't dangerous. There is nothing wrong with using them.

As for dangerous conditions, I'm more concerned about non-vented single line fuel tanks. Without a pressure relief valve like a pressure tank all the pressure builds inside the tank and gets much higher than a dual line tank ever could. Now you talk about a bomb.

Search the archives and read about pressure tanks.

 

[Chinewalker]

Re: pressure tank vs fuel pump

I agree - ever opened up an OMC steel tank on a hot day? Whoosh!! Or have you ever seen one of those plastic tanks blow up like a balloon on a hot day if the vent is closed? Yikes! Face it - it's gasoline and there's an element of danger no matter what the container...
- Scott

 

[coolguy147]

Re: pressure tank vs fuel pump

lol my mom one time left a jerry can directly in the sun until i told her not too and to put it away. lol ya i always keep the gas tank open a little to let air out cause it will goosh out of the line.

ya i know but ill probably change it anyways sometime

 

[jay_merrill]

Re: pressure tank vs fuel pump

I converted a pair of 1958 ERude Bigtwins to fuel pumps. One was done by drilling/tapping an original bypass cover to accept a fuel pump. On the other, I pulled a bypass cover from a frozen Johnson 33hp powerhead, and simply swapped it for the original on the Bigtwin. Both conversions have hundreds of hours on them at this point and never gave me any problems.

If you do a conversion, don't forget to remove the pressure nipple on the bottom of your intake manifold cover. Once you do that, fill the hole with a small screw/gasket, and make sure that you have the correct size/thread count for the screw. Also make sure that the screw is not too long - it will hit the leaf plate behind the cover if you don't.

If you don't have needle bearings in your motor, keep running the fuel mix at 24:1. If it does have needle bearings, 50:1 is fine.

PS: Notice in the photos, that the fuel pump mounted on the orginal cover is upside down. This is because the mounting point is very slightly higher than on the later bypass covers. If you don't mount the fuel pump upside down on the original, drilled/tapped cover, the top of the pump will hit the throttle control rod, during certain parts of its travel.