Trim pump question

[dish]

I am repairing a mates 2003 75hp mercury. He has left it out on his pontoon for 3 years since the last time i got it running for him.I just replaced the trim pump motor due to it getting completely eaten by rust.Now the pump motor is running but doesnt want to lift the ram.It tried to for a short time but **** itself!!!! I had a good look at the actual little hydrolic pump under the resivour,im thinkn maybe a diaphram in there has perrished or something.Has anyone ever pulled it apart and checked it out????? Whats in there???? The motor doesnt leakn down when sitting on the ram so im thinkn the seals in there are ok.Anyone ever serviced one of these?

 

[RRitt]

Re: Trim pump question

first, make sure that you used the correct length drive shaft between motor and pump.
second, after replacing motor, the system will need two or three cycles of topping off to fill the fluid.
third, do not run the system without tightening the manual release this can damage the pump
fourth, 2003 should be the newer square body pump which is virtually indestructible.

if it does get down to a broken pump then you will have to remove entire system from boat
and meticulously rebuild using the full kit including new poppets. I'm not sure of the
part #'s but it will end up being 2-3 kits. By the time you finish buying all the little kits it
will end up costing you $150-$200 in parts. Ya know ... if that's the case (full rebuild) then
it's not worth doing. I'm sure I have 5-6 spares of that pump design laying around.
dot your i's and cross your tees. pull the manual release and make sure all three orings
are solid along with the rounded tip. refill the fluids. if it still doesn't work then send me
a pm asking about a spare pump.

 

[Texasmark]

Re: Trim pump question

Did you think to fill with fluid and run the pump up and down to bleed the air out? Then top off the fluid even with the bottom of the fill hole.

Mark

 

[dish]

Re: Trim pump question

Thanks for the reply.Yeh im pretty sure its the right drive shaft adapter.The pump is the round body with the square resevour. I released manual trim and lifted motor and put it on its locking support.Filled with fluid but the only way to cycle is with the manual trim released.Will that still fill the ram??? Its a catch 22.

 

[RRitt]

Re: Trim pump question

There is no catch 22 when filling. You just run motor and top it off. If that doesn't work then something else is wrong.

when you change from one type of motor to another, you have to use a different length of drive shaft. If it is too long, then it will damage motor. If it is too short then it will fall out of socket.

I think that a standard 5/32" allen wrench is the same size as drive shaft. If your pump is the rocker arm design with round body then the driveshaft length is usually 1-13/32". A dremel with little cutting wheel does a great job of cutting correct length of hardened steel allen wrench.

 

[Texasmark]

Re: Trim pump question

Thanks for the reply.Yeh im pretty sure its the right drive shaft adapter.The pump is the round body with the square resevour. I released manual trim and lifted motor and put it on its locking support.Filled with fluid but the only way to cycle is with the manual trim released.Will that still fill the ram??? Its a catch 22.

The release is surely a pressure bypass which won't let you build up the pressure you need to force out the air bubbles. You need to do as RRitt said....up and down up and down. If just a fluid issue, after a few cycles it will start to move and the more you cycle it the longer the stroke till air is exhaled.

Mark

 

[dish]

Re: Trim pump question

The new pump motor is the exact same one i took off,so im assuming the shaft is the right length.When i screw the motor part to the resivour i have to line up the allen key shaft or it wont fit together.The trim moves is trying to work.It will trim a little up and down the stops.I will try and bleed it again

 

[RRitt]

Re: Trim pump question

yes, if new motor is exact same then old shaft is correct. I think sierra makes one that uses different shaft but you can tell it is different motor since it has slightly different size and shape.

don't run your system with manual release open. you can damage the system to the point that it needs rebuilding. If you have already done so, then block engine in place and fully remove manual release. inspect the manual release to make sure that all three orings are in perfect condition and that the tip is about 1/4" tall hemisphere past the last oring. If tip is missing then you need rebuild. it an oring is clean split then replace. it oring split with debris then don't run system until after you find & remove debris. If release is good then put back & never run trim motor without seating it.

it sounds like it might already be damaged.