question on trim trouble

[old islander]

Ok, my lower unit will not stay up. It slowly lowers itself back down. Takes abut 5 minutes to do this. Nothing is leaking and fluid level is full. Bond-o mentioned a while back it might be the check valves in the pump....or bad trim cylinder seals.
My question is two part.
1 can the check valves be replaced without replacing the whole pump assembly?
2 Is there a test I can do to determine if it is the valves or the cylinders?
I find that in a 50 50 situation I all ways go for the wrong one first. Don't want to buy a new pump and find out it's the cylinders....or vice versa.
Boat is a 77 islander with a 120 hp 153CI. inline 4.

Also, what drive would this be in 77?

 

[old islander]

Re: question on trim trouble

Anyone?....

 

[achris]

Re: question on trim trouble

Ok, my lower unit will not stay up. It slowly lowers itself back down. Takes abut 5 minutes to do this. Nothing is leaking and fluid level is full. Bond-o mentioned a while back it might be the check valves in the pump....or bad trim cylinder seals.
My question is two part.
1 can the check valves be replaced without replacing the whole pump assembly?
2 Is there a test I can do to determine if it is the valves or the cylinders?
I find that in a 50 50 situation I all ways go for the wrong one first. Don't want to buy a new pump and find out it's the cylinders....or vice versa.
Boat is a 77 islander with a 120 hp 153CI. inline 4.

Also, what drive would this be in 77?

Couple of things you can do.
Find some plugs and caps and plug and cap the lines from each cylinder in turn. If it stops dropping when one of the cylinders is disconnected, you found the cylinder. If it still drops with either plugged off, it's the pump.

Your drive is a Mercruiser-1 (MC-1 for short)....

Chris......

 

[old islander]

Re: question on trim trouble

Thank you Chris, I will give the plugs and caps a try. I should be able o come up with them at the local plumbing supply house for a few bucks. So the check valves mean buy the whole pump then? Jeff

 

[Bondo]

Re: question on trim trouble

Thank you Chris, I will give the plugs and caps a try. I should be able o come up with them at the local plumbing supply house for a few bucks. So the check valves mean buy the whole pump then? Jeff

Ayuh,.... Skip the Plumbin' Shop, 'n head to an Automotive Parts House,....

The trim lines use american Brake line fittings/ thread pitch...

 

[old islander]

Re: question on trim trouble

Thanks Bond-o The auto store is closer.

 

[achris]

Re: question on trim trouble

The check valves are in the pump, yes.