99 Merc 135 trim/tilt question.

Mazda3GT

Cadet
Joined
Jul 23, 2007
Messages
25
I recently bought an 18' larson with a 99 merc 135 v6, after putting it in the water I discoverd a slow leak in the power trim. This is what I have observed so far. After using the boat I tilt the engine half way, just submerging the cavitation plate, in about two hours it will leak down a few inches but the not all the way down, it will stay in that position forever. I have done this multiple times and it continues to fall down only a couple inches. I have also noticed what I believe to be hydraulic fluid in the water around the motor. I have also noticed that it gets more in fluid in the water when a wave comes, I think its the upper seal, I think that because it only seems to leak when that seal gets wet. I have the trim with the ram and the two pistions mounted externaly on the transom between the mounts. Also it sounds like there is some air in the hydraulic system, as it doesnt sounds 100% lubricated. I have searched some forums, but found my symptoms to be different then other posts. Any help is greatly appreciated. Thanks.

Steve
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 99 Merc 135 trim/tilt question.

Steve, My '93 Merc 135V6 has a single tilt cylinder in the center of the PTT unit, and two trim rams one on each side of the tilt cylinder. All of this is between the transom brackets. If you have cylinders external to the transom bracket, you likely have an older Merc, and need to find out what year.

Generally PTT units have orings and wiper seals on the external trim and tilt rods. If you see oil in the water, these are posible bad. See if you can see where the oil originates. Also, if a tilt unit leaks down, either the piston seal is bad (usually an oring) or the check valve is bad. You should be able to get a repair kit for the PTT unit, with all the seals and wipers etc, and a service manual for that motor.
 

Mazda3GT

Cadet
Joined
Jul 23, 2007
Messages
25
Re: 99 Merc 135 trim/tilt question.

Thanks Chris,
I think I described what i have wrong, I do have the one pump in the middle with the two pistons one on each side of the pump. I ordered a shop manual online and now Im going to start looking for a trim/tilt kit for my motor. thanks for the help, I really think, and hope it just an o ring or two.
 
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