79 Mercury 50HP power trim pump leak

[PGURNS]

The trim pump on my 50HP Merc. is leaking. It is leaking from the part that is bolted to the pump, I am assuming this is a valve body of some sort. If looking at the unit from the front, the leak is on the right hand side of the valve body. It appears to be coming from a hole about 1/16 inch in diameter. Is this a vent hole of some sort? Is there supposed to be a welch plug or something in it? (there are no threads in the hole).<br /><br />When topped off with fluid it works just fine until all the fluid leaks out. Also what is the reverse lockout function on the unit do?<br /><br />Thanks <br />Paul

 

[luv fishing]

Re: 79 Mercury 50HP power trim pump leak

ok first onmy 50hrs merc,on the cylinoid side, comeing from the big lines i have one hole that is 1/4 in. that is not pluged. all the rest are about 1/16 in. have small alan head plug in the rest of them. now on my tilt/trim it has a label that reads:Reverse lock operation. to release turn knob full right, to engage turn knob full left. CAUTION - DO NOT run boat unless lock is engaged. use sae 10w30 or 10w40. fill to bottom of fill plug theads with unit tilted up. the number on my pump is 76395A1. hope this is helpful.

 

[PGURNS]

Re: 79 Mercury 50HP power trim pump leak

Yeah the hole I'm talking about is on the side where the big lines come off of. It is sort of facing up almost where the motor meets the valve body. it looks as though there may be a spacer plate or something there too. <br /><br />Thanks for the reply I will try and take a picture of the area and post it<br /><br />Paul

 

[achris]

Re: 79 Mercury 50HP power trim pump leak

Paul,<br /><br />If the leak is coming from between the valve body and the pump reservoir, then one of the 'o' rings has failed. There are 2 sets of 4 'o'rings that seal the passages between the 2 units. No big deal to remove and replace. Hope this drawing helps.<br /><br /><br />

<br /><br />Chris...........

 

[PGURNS]

Re: 79 Mercury 50HP power trim pump leak

here is the best picture I could take of the thing

 

[PGURNS]

Re: 79 Mercury 50HP power trim pump leak

Chris, the leak is actually coming from a hole in part number 8 in the diagram.<br /><br />In fact the hole is almost exactly where there the line coming from the number 8 is pointing to. Thanks for the diagram.<br /><br />Paul

 

[luv fishing]

Re: 79 Mercury 50HP power trim pump leak

on mine the hole is there but nothing in it.

 

[PGURNS]

Re: 79 Mercury 50HP power trim pump leak

Thanks smaner, at least now I know something did not just fall out of it. I'll bet I have some o rings leaking internally or something.

 

[achris]

Re: 79 Mercury 50HP power trim pump leak

Paul,<br /><br />That 'hole' is just the way the casting is. Your leak is somewhere else, that's just where the fluid reaches the outside world. My bet, 'o' rings <br /><br />Chris...........

 

[PGURNS]

Re: 79 Mercury 50HP power trim pump leak

I had a feeling the leak was from an internal o ring. <br />I am going to take it aprt tonight and see what's going on in there.<br /><br />Thanks for all the input<br />Paul