Purging the trim pump

[clockwatcher]

I have a Merc trim system, single bolt through the bottom of the plastic reservoir, 1990 350Mag. The system had a lot of water in it (white milk). I rebuilt the cylinders, clean with new seals. Now I want to purge the pump. The pump is on the bench.

Can I fill the reservor with new oil and run the pump into a bucket without the lines attached, or will I blow parts out of the hose ports?

I just want to cycle the old oil out before I install it back into the boat.

 

[Bondo]

Re: Purging the trim pump

Can I fill the reservor with new oil and run the pump into a bucket without the lines attached,

Ayuh,... Sure, go ahead...

 

[Don S]

Re: Purging the trim pump

You won't get the old oil out of those reservoirs that way. Too many pockets inside the reservoir. Just remove the reservoir and clean it out, it's the only way.

 

[clockwatcher]

Re: Purging the trim pump

Thanks.

I was just worried about blowing parts out of the pump with the hoses detached. I read somewhere that it's a 2600 psi pump. That would be my typical $200 lesson learned. It's better to ask those who know first.

I cleaned the reservoir with soap and hot water. Poured in new fluid. Stuffed a piece of hose (5/16" OD) into one port and ran it back into the reservoir cap hole (otherwise it will suck air). Hooked up the battery and bridged the the solenoid to run the pump. All clean now.