trim pump oil refill?

betayv

Senior Chief Petty Officer
Joined
May 13, 2008
Messages
706
hello there 1979 mercruiser with a 305/228 and a alpha one leg one of the trim pump hoses blow I just replaced and try to add oil and I just hear the pump working but is not going either up or down, I think I need to flush the system but Im not sure how to do that, I know you guys will send me to the top section to download the manuals, I try that already and I dont know why after waiting to the manuals donwload complete I cant open it, the hose that blown was the number 1 on the pic below any help thanks again.

http://images.google.com/imgres?img...ages?q=trim+pump+hoses+mercruiser&gbv=2&hl=en
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: trim pump oil refill?

Be sure you don't have shifter in reverse.If all you did is replace one hose there should be no problem as it should bleed itself quickly.
 

betayv

Senior Chief Petty Officer
Joined
May 13, 2008
Messages
706
Re: trim pump oil refill?

is on neutral and like I said I fill up with oil and I only can hear the pump working but is not going up or down
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: trim pump oil refill?

Disconnect the lines on one of your trim cylinders and see it it squirts out those lines as you work the switch up and down.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: trim pump oil refill?

You need to open the bleed screw on the pump in order to let the air out of the system. As you move the trim up and down with the bleed screw open, the air will let out.
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: trim pump oil refill?

I have never seen a bleed screw on a mercury trim pump.When fluid RETURNS to the reservoir either from the UP or DOWN line any air will bubble to the surface in the reservoir.Any fluid LEAVING the pump either UP or DOWN goes out the pump in the bottom of the reservoir where no air can possible enter unless you let the reservoir go empty.There for the system bleeds itself just by running the pump up and down.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: trim pump oil refill?

I have never seen a bleed screw on a mercury trim pump.When fluid RETURNS to the reservoir either from the UP or DOWN line any air will bubble to the surface in the reservoir.Any fluid LEAVING the pump either UP or DOWN goes out the pump in the bottom of the reservoir where no air can possible enter unless you let the reservoir go empty.There for the system bleeds itself just by running the pump up and down.

He said he replaced a blown trim hose! That would introduce air into the system! I'm willing to bet that with it being a 79 model, it probably has one of the older prestolite trim cylinders (my boat, a 76, does) and it has a bleed screw just above the fill screw on the METAL resevoir. In any case, the bleed instructions are in the "adults only" sticky at the top of the forum in the manual for your year of boat.
 
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