outdrive won't stay up.

[wet dog]

I've got a '90 bravo 2 outdrive with an oildyne trim pump that falls after several hours, and falls down fairly quickly under pressure on the water. I've replaced the seals in both hydraulic cylinders and purged the air completely. After a couple cycles it seems to suck air in again from somewhere, as I can hear a change in the pitch of the pump motor. I can find no fluid leaks so I'm assuming it's coming from somewhere in the pump body. I can hear air in the pump only when triming down. It's sounds fine when triming up. Anyone had this problem with this pump?

 

[hoot]

Re: outdrive won't stay up.

on my older pump ('78) there is a plate under the pump that has passages to the cylinders in it. these holes have orings around them to seal. sometimes the orings will fail allowing the unit to fall. pita to pull and replace orings but must be done.

 

[wet dog]

Re: outdrive won't stay up.

thanks

 

[Capt.T]

Re: outdrive won't stay up.

I have got the same hydraulic pump on my Mercruiser. There are 4 small o-rings above the bottom plate. It is very difficult to remove the pump due to tight space and wiring, but there is no other way to remove plate and change o-rings. Once you change the o-rings, the pump will self purge and work fine. I have had to replace the o-rings twice in 6 years.<br />Good Luck.....

 

[wet dog]

Re: outdrive won't stay up.

ok, I've removed the pump from the boat then removed the motor from the pump frame. I've only found two 'O' rings, one sealing the pump frame around the resevoir and another sealing the motor on the pump. There are 3 nozzles, and one intake with a screen. I've taken off the nozzles and found no 'O' rings. Everything looks in good shape. What 4 'O' rings did you replace?

 

[hoot]

Re: outdrive won't stay up.

on my pump( remember it is a '78 model), there is a manifold block under the oil reservoir. the hoses attach to the block. this block comes off and the o-rings are internal to this block. if yours is different, maybe T can help locate the o-rings.

 

[johnkc]

Re: outdrive won't stay up.

your pump is not like the ones described with the replacable control valve on the bottom.replace the pump , also called an adapter. although you see nothing wrong there is an internal leak letting the drive fall.

 

[wet dog]

Re: outdrive won't stay up.

Are any of the internal parts servicable?

 

[johnkc]

Re: outdrive won't stay up.

they used to be but i don't know if they still are .by the time you had in them replacing valves and testing them it ends up cheaper to replace the adapter.

 

[wet dog]

Re: outdrive won't stay up.

Do you think I need to replace the pump along with the adaptor?

 

[johnkc]

Re: outdrive won't stay up.

the pump is the adapter,i don't know why merc calls it an adapter because it is a pump.hope this doesn't confuse you.

 

[wet dog]

Re: outdrive won't stay up.

On all the diagrams that I've found, there is both an adapter, and a seperate pump.

 

[johnkc]

Re: outdrive won't stay up.

replace the pump

 

[wet dog]

Re: outdrive won't stay up.

ok, thanks