Won't pump from tank; Works on muffs !

[theoldwizard1]

2001 Mercury 115hp 4 stroke EFI

So a couple of months ago, I bought a large plastic storage box and made a frame out of 2x4s to hold it so I can use it as my test tank. (Came out pretty decent for someone with no carpentry skills.) Yes, I am behind in my boating preparation, but today I filled the tank and dropped the foot of the motor in. Motor started right up (EFI is great), but no tell tale. (Yes, the inlet ports were well covered with water.)

So I drained the tank and started looking for a mechanic. Then I decided to try the muffs. Strong tell tale !!

The motor was tilted at approximately the same angle both times. WHY DIDN'T MY TEST TANK WORK ?

 

[theoldwizard1]

Let me add that I disconnect the water line to the fuel cooler assembly in fall so that it and the rest of the cooling system can thoroughly drain (water in the fuel cooler caused it to split the first winter I had the boat). I re-attached this line before starting the engine, I waited a good 60 seconds after starting before shutting the motor down so I assumed that was long enough to "prime" the cooling system.

 

[racerone]

Covering intakes with water simply is not good enuff.-------Water must be 6" above the pump for this to work !

 

[theoldwizard1]

Covering intakes with water simply is not good enuff.-------Water must be 6" above the pump for this to work !

Well, maybe not 6" above the pump, but certainly above the pump housing !

I adjusted the angle of the trailer and the motor as well filled my tank to the very top. It was clearly at the "waterline" mark left on the leg. Strong tell tale !

I might need an additional spacer under the trailer tongue wheel to increase the angle of the boat and then correspondingly adjust the angle of the motor. (A taller "tank" would be perfect, but I was lucky to find this one.) I also need a short piece of garden hose with a male threaded end to screw into the tell tale hole so that the water goes back into the tank and not down the driveway causing me to refill the tank !

The top of the tank (sitting in a frame if required) should be at least 24". 30" would be better. My tanks interior is only about 21" deep, but playing with the motor tilt angle it is sufficient (just barely).

FYI, once the engine is running and water is flowing, the surface tension of the water will allow you to raise the foot up to the point of just having the inlet ports under water.

 

[wired247]

Your impeller is no good or the thermostats werent open. Mine are barely covered and still knock out 10 PSI at idle.