Originally Posted by Cole2534

If your mechanical fuel pump bolts to your block disregard, but if your mech pump bolts to your impeller housing then follow along-

Unhook the lines from the mech pump and then unbolt it from the impeller housing. In that cavity there is the impeller shaft and on it the cam lobe that actuates the fuel pump foot. This cavity should be filled with merc gear lube, but in some gases gasoline can leak from the mech pump and dilute the oil. This will ultimately result in failure of the fuel pump to do it's job properly. So whenever you pull your impeller you should pull off the fuel pump. pull out the old oil with a syringe or similar and refill with gear lube.

Attached is a pic of my fuel pump after I lost a seal and evacuated the gear oil to my bilge via the v-belts. Different cause, same end result. Please note wear on the pump's foot.

Originally Posted by Tractionless

What do you recommend for "gear lube", same amsoil that goes in outdirives or other?

Originally Posted by Baja Rooster

Do the dry run impellers really work? It seems like that with a SS housing would be nearly indestructible.

Originally Posted by HyFive578

I've been using standard Mercury High Performance Gear Lube (same stuff as in my drives), although I am switching my outdrives to use Torco RTF instead for this season.

Originally Posted by flatlanderbill

If I have the whole assembly off , I rebuild the whole thing. Housing , impeller, seals , bearings , fuel pump gasket, even the wear collar the cam lobe rides in for the fuel pump. Too much of a pain to remove to not go thru it completely. Do it every other season.

Originally Posted by Sydwayz

Most people have found that the run dry impellers do not pump as much/enough water as the old fashioned kind.

Originally Posted by Tractionless

I cracked the inspection screw on both of mine and immediately was met with a plume of fuel (smell). Can I take said screw out, suck out all the fluid with a hose on the end of a syringe and then refill with gear lube with a syringe while still on the motor?

Originally Posted by flatlanderbill

If I have the whole assembly off , I rebuild the whole thing. Housing , impeller, seals , bearings , fuel pump gasket, even the wear collar the cam lobe rides in for the fuel pump. Too much of a pain to remove to not go thru it completely. Do it every other season.

Originally Posted by Tractionless

Bill what seals are changeable? Diaphragm that separates the fuel and lubricating oil? I had heavy fuel smell and much dilution in mine. I hear this can cause the shaft bearing to go out.

Originally Posted by Tractionless

Bill what seals are changeable? Diaphragm that separates the fuel and lubricating oil? I had heavy fuel smell and much dilution in mine. I hear this can cause the shaft bearing to go out.