'84 Mariner 150 tilt and trim leaks down

[prestridge]

When the tilt is actuated, the motor raises and lowers fine, but when in the up position, will fairly quickly sink back to the down position on its own. What needs to be fixed to correct this leak-down problem?

 

[Texasmark]

Re: '84 Mariner 150 tilt and trim leaks down

Get you a service manual. All the things that make it work are described and it is more complicated than you might think because of all the do this and do that valves in there.

Mark

 

[Chris1956]

Re: '84 Mariner 150 tilt and trim leaks down

randallP, If that is the two ram, external pump-style PTT system, the condition is either caused by a bad teflon piston seal, or a bad check valve. I have never had a bad check valve, however. You can isolate a bad piston seal by disconnecting each cylinder in turn and plugging the hose ports on the pump. Since the cylinders are connected in series, if either one has a bad seal, both will leak down.

 

[studlymandingo]

Re: '84 Mariner 150 tilt and trim leaks down

I have an '86 mariner 150, my money is on the piston seal if there is no external fluid on the pump.

 

[studlymandingo]

Re: '84 Mariner 150 tilt and trim leaks down

Easy to obtain, not as easy to replace. The biggest issue I had rebuilding my trim was locating a spanner wrench to fit the unit. I ended up making one out of a ford pulley tool and a couple of broken drill bits. Taking the piston pin out was a bit of a bear also. You may want to do a search and find my old post here where I did this procedure.

 

[prestridge]

Re: '84 Mariner 150 tilt and trim leaks down

Thanks for the input, there is no external fluid leak. I just bought this boat, and plan to obtain a manual soon. Is this piston seal easy to obtain and replace?