Mercury Power Trim Not Staying Up

[Missouri]

Have a 1982 Mercury 115EPT. Power trim motor works, but eventually trims back in after a minute or two under power. Replaced valve body assembly, but no improvement. What manuals do I need to invest in that diagram the power trim system for this model? There is a pressure checking procedure, but I've not seen the documents and Mercury doesn't have any information on engines that old.

 

[Waterbugtoo]

Re: Mercury Power Trim Not Staying Up

If you've replaced the valve body, and you know for a fact it is good, then about the only thing left is the rams bypassing fluid, unless you have an unseen leak somewhere.<br /><br />

 

[Missouri]

Re: Mercury Power Trim Not Staying Up

Thanks for the reply, Waterbugtoo. New valve body assemblies aren't available to the best of my knowledge. I bought valve body from a boat parts house in Florida that appeared to be reputable and claimed that it was from a fully working system. Hence, I can only assume it is good. I switched my old one and the replacement several times and got the same result. In fact, I replaced one of the pistons with a new one that I was lucky to find and interchanged the pistons several times. I've bled the system more than once and replaced with Mercury trim fluid. The problem began after a marina topped off my reservoir with 30 wt oil some years ago. There are no visible fluid leaks and the motor will stay up on its own for weeks until it's under power. I would like to know the procedure for pressure checking the system before I "throw more money at it". A Mercury mechanic told me there was a procedure some years ago. Hence, I need to find the documentation to pressure test and would like to know if it's in any currently available manual.

 

[clanton]

Re: Mercury Power Trim Not Staying Up

Where is the electric motor and hyd pump/ valve body located?

 

[Waterbugtoo]

Re: Mercury Power Trim Not Staying Up

I kinda figgered it was a used one. You might also try checking for trapped air bubbles. Raise motor to full tilt position and prop up. Remove down bleed screws on each cylinder one at a time and depress down button for a couple of seconds. Repeat for up bleed screws on each cylinder depressing up button as well. If air is present anywhere, that may be causing the problem, but I would be more apt to say its probably a bypassing problem. Current manuals dont have a pressure check procedure, so unfortunately I dont have numbers. Sorry I cant be of more help.

 

[Missouri]

Re: Mercury Power Trim Not Staying Up

Thanks for your replies. Clanton, the valve body is where all the hoses connect to the underside of the reservoir inside the boat's rear compartment. As I recall, valve bodies are engineered at the factory and can't be rebuilt. Waterbugtoo, I might take another shot at bleeding it, but am confident I've been thorough. I bled it by reversing the position of the pistons (so the screws were pointing up) and attached a fitting and several feet clear plastic hose into reservoirs of Merc trim fluid. That way, I can see when the fluid runs clear and bubble free as well as close the screws without losing any. However, my conclusion matches yours -- I think there's a bypass somewhere, but buying a bunch of expensive, hard to find parts that may or may not fix it is what I'm trying to avoid. After all, the motor (strong in every other way) is only worth about $500. Of course, that's a lot less than paying about 8K for a new one that wouldn't even keep up with it.

 

[clanton]

Re: Mercury Power Trim Not Staying Up

I have Clymer manual ISBN 0-89287-396-5 but, but can not id the pump on your engine. With a diagram of the pump, you may be able to disassemble the pump/valve body and repair the valve. I repair the integral system on later model Mercury V6s, and the 125/150 Force. Most of the time you can repair the leak down on these 2 pumps for less then 20.00 US, plus labor. Im not looking for work. You could remove all of the hoses from pump, make adapter and apply air low air pressure ( 40 LBS OR LESS) and verify pump/valve body leak down. I would remove fill cap and stand on the other side of pump when you apply air, you may get a hyd fluid bath. I would also remind you that this system may make hyd pressure from 1200-1600 lbs, which is enough to push the fluid under the skin, so dont use your finger to check the pressure.<br /><br />Edited 30 dec 02 If you can find fig of pump in the above manual, post the fig. number.

 

[Missouri]

Re: Mercury Power Trim Not Staying Up

Clanton, my engine model is 1115622 (still have my original registration card). The pump assembly is Merc part#92975A32 and the control valve assembly is part#45197A2, but is no longer available. My current plan is to buy all the "O" rings between the control valve assembly and the manifold plate (did that once before, but worth another try). The information about lbs. of pressure is part of what I was looking for and will attempt before and after rebuild. Of course, I'll check the pistons also. If it has information on the trim system model that I've stated, I would definitely be interested in buying a manual (I assume you're a parts reseller or such). My only question is whether there are internal parts in the control valve assembly that could be the problem since it is no longer available and there is no rebuild kit. I will see if I can contact someone at Mercury (last guy didn't know anything about this engine). Thanks.

 

[clanton]

Re: Mercury Power Trim Not Staying Up

Not a parts seller, but I use to have a few check valves for the Force engine. Since you posted serial numbers, I will look in parts book for break down. My guess in the problem is inside the pump body, where the check valves are.

 

[clanton]

Re: Mercury Power Trim Not Staying Up

I think I have found a hyd flow chart for the pump/valve body. The chart shows hyd fluid flow for each hyd circuit, and the position of the check valves. With the chart you can tell which check valve is the problem. My scanner is down again, so the only way I can help you is e-mail at me clanton@atlantic.net

 

[clanton]

Re: Mercury Power Trim Not Staying Up

B

 

[Missouri]

Re: Mercury Power Trim Not Staying Up

Thanks, Clanton. I owe you one. I'll e-mail direct to you. The diagram should allow me to at least determine if the valve body is the problem and not somewhere else.

 

[mopig]

Re: Mercury Power Trim Not Staying Up

I am looking for same charts cam you send them to me to thank you . mjosborne1@hotmail.com