Plumbing to feed one motor from two tanks

[jtexas]

I have a pair of portable tanks which I would like to connect with a valve so that I can use them sequentially and switch from one to the other without disconnecting and reconnecting.<br /><br />Is anyone set up like this? What kind of valve? Would I need two primer bulbs upstream of the valve, or would one on the motor side do the trick?<br /><br />Thanks!<br />john

 

[Chris1956]

Re: Plumbing to feed one motor from two tanks

JT, There are valves made for this application. They are called 3-way valves (Item 140030, $24.99 in Boaters World catalog) You can connect the valve to two pieces of rubber fuel line with tank quick disconnects. The third port on the valve connects to the primer bulb and engine quick-connect.

 

[phatmanmike]

Re: Plumbing to feed one motor from two tanks

 

[jtexas]

Re: Plumbing to feed one motor from two tanks

great, thanks, guys. the description says it's for permanent tanks, but I assume that's more a general guideline than actual rule?<br /><br />anyway so I would use fittings like these, right?<br /><br />

<br /><br />Is there some kind of tape or sealant I would apply to the brass-to-brass threaded connections?<br /><br />thanks!<br />john

 

[phatmanmike]

Re: Plumbing to feed one motor from two tanks

 

[mrloring]

Re: Plumbing to feed one motor from two tanks

Teflon tape<br /><br />You can pick it up at any hardware store, even Walmart. Less than a buck. When you apply it be sure to wrap it clockwise (while looking at the threaded end) so that it will not unwind when you put the pipes together.

 

[Dhadley]

Re: Plumbing to feed one motor from two tanks

Be real careful using the tape. Make sure to keep it away from the end of the fitting. If it gets cut and a piece gets in the fuel delivery system it could create major problems.

 

[bossee]

Re: Plumbing to feed one motor from two tanks

Hi,<br />There is special sealing for fuel connections, it was used on my fuel/water separator (do not know the name of the sealant). It looks like grease and is almost transparent (almost wax like).<br /><br />See also my post yesterday: Fuel selector valve<br />Yamaha also sell a selector valve.

 

[Perfidiajoe]

Re: Plumbing to feed one motor from two tanks

Unless I misunderstood, that valve won't work for what you want it to do. That valve connects 2 tanks to the motor & you select, by turning the switch, which tank you want to use. Only 1 tank at a time will be used! Be carefull hookung two tanks together, If not done right you could suck air if one tank goes dry. be carefull with the plumbing, fuel leaks & fire are no fun. Good Luck, Joe

 

[Perfidiajoe]

Re: Plumbing to feed one motor from two tanks

Unless I misunderstood, that valve won't work for what you want it to do. That valve connects 2 tanks to the motor & you select, by turning the switch, which tank you want to use. Only 1 tank at a time will be used! Be carefull hookung two tanks together, If not done right you could suck air if one tank goes dry. be carefull with the plumbing, fuel leaks & fire are no fun. Good Luck, Joe

 

[jtexas]

Re: Plumbing to feed one motor from two tanks

theoretically, if I put a primer bulb between each tank and the valve, could I switch while the engine is running?<br /><br />didn't realize teflon stands up to gasoline, thanks guys.<br /><br />perf, I appreciate the advice, but I prefer use up one tank then go to the other, as opposed to drawing from them in tandem. This way I can always use FIFO (first in first out), and simplify premixing by only having one partially empty tank. And some days I don't use the second tank anyway. This is what I do now only I have to move the fuel line. Really just a minor inconvenience, true, but an easy mod. I used to run tank#1 dry before switching until I learned the consequences here on iboats.

 

[dajohnson53]

Re: Plumbing to feed one motor from two tanks

Hey, I use that valve all the time, for over 10 years. I draw from one tank, then switch to the other. If I run out in the first tank, I have to pump the bulb after I switch to the second. If I switch before running out, no additional priming is needed. <br /><br />It is not a problem it is what the valve is designed for. My tanks are permanent, but I can't imagine why they wouldn't work with portable tanks. The connection to the valve would be permanent, but the quick releases to the tanks would still be there. The primer bulb goes just before the engine - after the valve. You'd have two new fuel lines for your tanks - permanently attached to the valve, quick release at the tanks, without primer bulbs. Your output line from the valve to the engine would have a bulb fairly close to the engine. You'd keep your old fuel line (with quick releases and bulb) to use with your tanks if needed in other settings.

 

[Sherman]

Re: Plumbing to feed one motor from two tanks

I have two plastic tanks under my center console and mounted the three way valve just above the tanks to the console shelf. I use only one line to the engine and put the primer bulb just behind the valve so if I do run out of gas in one tank I don't have to run to the back to prime. I would suggest that you mount the bulb as vertical as possible with the output end up as most do not have spring loaded check valves and can be hard to get pumping if they are horizontal.

 

[Perfidiajoe]

Re: Plumbing to feed one motor from two tanks

I guess I did misunderstand, that will work for selecting 1 tank at a time. Left & right inlets to your tanks, center to your primer ball then on to the motor. sorry I thought you wanted to feed 1 tank into another.

 

[Bob Kimber]

Re: Plumbing to feed one motor from two tanks

Jtexas,<br /><br />I would be extremely carefull using standard "teflon" threadseal tape on your gas fittings, in Australia it is illegal for use on any petroleum based product as it will eventually break down and dissolve with possible explosive results, the cheaper the quality the faster this may occur. <br /><br />Dupont (and maybe others) makes a specific teflon tape for use on LPG and other gas pipe fittings (petroleum based product), this is generally a yellow colour and is available at hardware stores also, for only slightly more cost, it will specifically state on the roll of tape it is approved for gas use. I have posted warnings on this in the past and received a lot of negative comments, but as someone who has been a licensed plumber & gasfitter for 39 years and was also a quality assurance rep and safety officer for a government dept. for 33 years, I have seen the results of ignoring the safety reccommendations.<br /><br />I have 2 permanent underfloor SS tanks I made myself over 20 years ago, they are independently filled and vented, with two lines to my filter/water separator which has a double manifold inlet with a SS ball valve on each inlet. I have kept the original idea of a primer bulb between the filter and motor, with another primer bulb on the inlet line of the rearmost tank, if the boat has been sitting for a while I prime the motor using the bulb on the rear tank, but in most cases just use the primer bulb near the motor, I installed this setup about 1983 and it has worked fine since then on 2 different motors.<br /><br />Bob

 

[alden135]

Re: Plumbing to feed one motor from two tanks

Ditto on the teflon tape. Home Depot sells the yellow stuff in the plumbing department next to the cast iron pipe. I have had white teflon tape dissolve from gasoline exposure (but I don't remember where I bought it from).

 

[mrloring]

Re: Plumbing to feed one motor from two tanks

Thanks for info about the white teflon tape. I did not know it was not suitable for use with gas. I will be changing mine soon.