Tilt / trim internal leak

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
I need help in diagnosing and repairing an internal leak in my tilt / trim system.
When in full tilt, it will come down to zero tilt in about half an hour and there are no external leaks.
The motor is a 1988 60hp. but I think the trim system may be older since the pictures, descriptions and fluid specs in my owners manual differ greatly from what is actually installed on the motor.
The sticker on the pump says to use 10W30 but the 1988 Mercury owners manual says tranny fluid?? According to my Seloc manual, it appears to be a "Type A" system.
I was advised in an earlier post to look at the seals on the manual release valve first, but my Seloc manual doesnt identify this item. Do type A systems have a manual release valve and is it possibly called somthing different in the manual?
Also, the troubleshooting page in the Seloc manual says it could be a leaking check valve, but once again, this item is not identified in the parts schmatic, where is this check valve located? Sorry for the long winded post, but I really require some assistance.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,124
Re: Tilt / trim internal leak

Aerocook, Is the PTT the one with the two cylinders and external trim pump? If so, a leakdown can be caused by the control vlave, which is non-rebuildable. It may also be caused by a worn out teflon piston seal in one of the trim cylinders.
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Re: Tilt / trim internal leak

Thanks Chris. Yes it is the system with 2 cylinders and an external pump. Any Idea on the cost of a control valve? Is there any way to pinpoint the leak or do you just start replacing stuff till it's fixed?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,124
Re: Tilt / trim internal leak

Aerocook, It is tough to isolate the problem. The trim cylinders are connected together, so if the piston seal in one is bad, both cylinders will leak down. You could remove and cap the lines from one cylinder and see if it leaks down. If not, you have found the culprit. I think it unlikely that both cylinders have bad piston seals. I also think it likely the control valve is good.
 
Top