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-   -   VST or Aeromotive? (https://www.offshoreonly.com/forums/general-q/334470-vst-aeromotive.html)

buck35 02-16-2016 12:41 PM


Originally Posted by ezstriper (Post 4404597)
two easy ways to do return are to drill/tap sending unit or buy a replacement for a diesel as they put a return in there, of one of the adapters that go in the fill hose..

Been looking around for the diesel with return built in , either I'm doing something wrong or there are not a bunch of choices..
the bulkhead fitting idea still piques my interest though, but......

edit , not to wild about running a hose through cockpit to fuel filler

AllDodge 02-16-2016 01:01 PM

Not so much the fuel filler but the fuel filler hose. Cut the hose and use a Tee fitting. Just info of how others have done it.

Have a good one

ezstriper 02-17-2016 07:11 AM

here's the diesel sender with return

http://www.go2marine.com/product/384...turn-6-24.html

Langston 02-17-2016 07:25 AM

Just a thought because the vst is not one of merc's greatest inventions even when new , bur in a nutshell it's designed to maintain enough pressure to prevent vaporization of the fuel. The diaphragm was revised early on and most were changed or had a tank replaced with the rev version that had a clear hose on top. The fitting that that clear hose connects to on the plenum can become clogged and not vent the excess pressure , weak mechanical fuel pump can't overcome the excess pressure and then you crank run and die when the HP pump sucks the tank dry. Or don't start at all if the diaphragms leaking and not holding pressure and the fuel vaporizes. Very aggrivating. A boost pump kit helps. Merc has a nice kit that's easy to install.

buck35 02-17-2016 07:31 AM


Originally Posted by ezstriper (Post 4405040)
here's the diesel sender with return

http://www.go2marine.com/product/384...turn-6-24.html

Thank you sir!

buck35 02-17-2016 07:47 AM


Originally Posted by Langston (Post 4405049)
Just a thought because the vst is not one of merc's greatest inventions even when new , bur in a nutshell it's designed to maintain enough pressure to prevent vaporization of the fuel. The diaphragm was revised early on and most were changed or had a tank replaced with the rev version that had a clear hose on top. The fitting that that clear hose connects to on the plenum can become clogged and not vent the excess pressure , weak mechanical fuel pump can't overcome the excess pressure and then you crank run and die when the ho pump sucks the tank dry. Or don't start at all if the diaphragms leaking and not holding pressure and the fuel vaporizes. Very aggrivating. A boost pump kit helps. Merc has a nice kit that's easy to install.

Very aggravating would be an understatement, lol
I have had some success by putting a wet or iced towel on the vst tank to draw the heat out, but it may have been just the extra wait time. Pain in the arse for sure when it happens.

Cole2534 02-17-2016 11:27 AM


Originally Posted by camptappakeg69 (Post 4404418)
How does it bleed excess pressure without a return? Noticed mine started started idling like crap after a couple hard runs, vst float or needle is stuck or the diaphram is ruptured or any other issue inside because there is raw fuel in the clear hose that feeds back to the mech pump. Also is dumping raw fuel into engine, was afraid it was going to wash a cylinder so I parked it for the season

I have a return, it just doesn't go to the tank.

The excess fuel goes to the low side of the pump, suction, and the pressure dissipates as soon as it goes across the regulator. The engine is going to use whatever the engine is going to use, so the less excess that gets pumped the better off the system is because it means you're drawing more fuel the tank.

BUP 02-23-2016 02:51 PM

have no idea about what or how these Holley pumps would work out ? Just posting to see

http://www.dynosty.com/2016/02/holle...to-new-levels/

camptappakeg69 02-23-2016 08:05 PM

Ordered aeromotive pump,filters and regulator for the project. Starting it soon, thought my tank had an extra bung but it doesn't. Might try the return like Cole did to the low side of the pump or drill and install another bung into the tank. Don't really want to return all the way to the filler hose with a tee, only access to that is up near the helm I believe.

ezstriper 02-24-2016 06:41 AM

the main issue with whole deal was no return to the tank witch kept the fuel hot and lead to the vapor lock deal, dumping it into the suction line of the pump is the way merc did it and did not work, by not returning to the tank 90% of the fuel cooling is not accomplished.


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