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We solved this problem by removing the aluminum fuel fills, drilling and threading them to accept a 1/2" X 5/16" hose barb where they normally extended below the sides. We reinstalled the fills and threaded in the hose barbs through the aluminum fills and then into a 90* fitting with a braided line down into the tank. We then ran the return through a switch to each of the tanks through the hose barb set up. The only problem is that you have to watch carefully when filling up the tanks because the returns do obstruct the fuel fills slightly.
why is the fuel cooler never between the pump and the motor in these set ups? to keep the pump cool?good thread i'm learning .
I use a merc PS cooler (the good one with the tube bundle) as a fuel cooler prior to return to the sep/filter head. They are like $95 and work just fine. If you don't do something to cool the fuel the pump/return looping of the fuel will just heat it up and cause problems.
The problem with returning the fuel to the seperator is that in July at Havasu the chance for vapor lock is very high. I had that problem all last summer. I am in the process of moving the returns to the tank fills with something similar to the ones shown earlier in this thread from CP. In a single engine/dual tank when it has already had fuel in it, make a flange with a return bung welded into it, it will look similar to a fuel sending unit. Make a gasket (fuel safe) and screw it to the top of the tank away from the pick-up. Then use the Imco 6 port fuel valve, 2 for the supply and 2 for the return. (liability disclaimer) Make sure the return is completely sealed with a gasket at the flange and where the screws go into the tank.
I have been returning through a fuel cooler and then back to the water seperator. Never had an issue and the fuel going to the pump is always cooled somewhat from the -6 or -8 return line.
Did this due to the duel tank issue and no bungs in the tank for return lines.
Here I put a tank fill and return hose point into my fuel tank. The return is a 3/4" bushing with a 1/4" NPT on the top, which connects to a 5/16" hose barb.
The original return was into a y-fitting on the fuel tank fill.
Originally Posted by Notalent The customer im dealing with says that his tank does not have a return into the tank and noone will weld one in.....what happens in this case....? Will the IMCO Fuel Valve fix the dilemna? Uh, no. Returning to separator is best solution in this case. IMCO valve just allows you to switch between feed & return, but if the tank(s) has no return(s), you still need to go with something different. Big separator filter is best alternative to give most thermal mass to dissipate heat before reaching the carb/injectors. Not such a problem with smaller pumps, but the big high pressure EFI pumps can run pretty warm and add significant heat to the fuel.
Originally Posted by Notalent The customer im dealing with says that his tank does not have a return into the tank and noone will weld one in.....what happens in this case....? Will the IMCO Fuel Valve fix the dilemna? It is best to get the return fuel back to the tank. IMO
A lot of people return it back to the water seperator. Use one that has 4 ports (2 outlets, 2 inlets) and mount the pump after (and lower) the seperator. Use a normal fuel filter after pump.
Mercruiser does this also, but uses a fuel cooler (looks + is like small oil cooler) to make sure there is no fuel heating issues.
I have not done the above, but I have done the following on single tank applications : http://www.cpperformance.com/SearchR...CategoryID=379
The fuel fill hoses I did these in where 2" ID. If you don't have this fill hose ID nor single tank, then this won't work for you.
The customer im dealing with says that his tank does not have a return into the tank and noone will weld one in.....what happens in this case....? Will the IMCO Fuel Valve fix the dilemna?
I just split the lines back to the tanks. -10 to the regulator -8 out to two -6 lines. Never had a problem with tanks not being equal.
IMCO makes a really nice fuel selector switch/valve
made just for EFI. 6 port. 1/2 " it swiches feed and return and
sending units. pricey but nice http://www.danamarineproducts.com/Pr...TOKEN=59965491
If your returning to the tanks just run your return line to a tank selector valve(just one to switch from left to right). From there you just make sure your returning from the same tank your pulling from.
Originally Posted by Notalent Is there any reason why it wouldnt be able to dump back into the fuel tank?
Thanks for the info. No, as long as you're running one tank. If it's a boat with two side tanks, it can be a problem with only one return line.