Mercruiser Gen II trim problem

[CastleRock4me]

Trim has trouble moving up (very slow). Rams are good, can't find any leaks anywhere in the lines. However the pump struggles and aerates the pump oil (and appears to be leaking a bit of oil, can't tell from where). I have bled the system a couple times and it improves for one cycle then back to barely moving.

Any ideas? I have searched to no avail.

Thanks

 

[achris]

The inlet strainer in the pump reservoir may be blocked. Pull the reservoir off and check it...

Chris.........

 

[greno]

I've also seen people dump the wrong oil in the reservoir with too much viscosity and it slowed the pump down to where it would move the rams very very slowly.

 

[CastleRock4me]

Using 10w40 oil. Gonna take the pump out and have a look at it in the next couple weeks. Should I just replace the pump? Are they they easy to rebuild?

Thanks

 

[harringtondav]

Parts are inexpensive in boating term's. But I'd follow the advice above before you take that plunge. The correct oil is strangely vague. I use straight 30W. I've heard power steering fluid or ATF work.

It sounds like you have aeration and cavitation. Start with achris to be sure your pump isn't starving for oil.

My trim failed last season at a critical guest time. I Googled the Merc. assy and found a complete assy for $260 new. Still have the 21 yrs old one on my bench. Someday I'll find the bad $20 part.

Diagnosing the pump and valve body takes the manual and a high pressure test rig. Start simple, then go for the $260 after market. I suspect marine shop $$ will justify this.

 

[Oshkosh1]

If it's not detritus in the strainer then there's probably and internal seal issue which in that case...it's time for a new one. I saw them on Amazon for $250 or so a few weeks ago...the whole shootin' match. Four scews, a plug, a ground and two hydros and you're golden.

 

[TurtleTamer]

How do you know the rams are good? Did you isolate each one and test it by itself? I went through the whole ordeal recently myself. All you need is the right plugs to install in the trim manifold at the bottom of the outer transom plate. Remove lines, install plugs, disconnect ram from pin and test.