Power trim help please................

[fin-bender]

Hi, I am new pretty new to the boating world, and have been learking here a bit. I decided to register to ask a question. I have not been able to find an answer.

I have a 1998 Merc 115 2-stroke motor and I was wondering if my tilt/trim is working properly. There appears to be a single ram that lifts the motor. Does this mean that I only have a power tilt system ( and not power trim) or is it some type of hybred tilt/trim system?

Last weekend I was at just over idle speed and tried to tilt the motor up, I hit the up toggle on the throttle and it appeared that nothing was moving. I then put the boat in neutral and was able to lift the motor, it came up quickly. This lead me to wonder if something might not be working properly.

Could some review how the tilt and/or trim works on this motor and how I could do a systems check to see if its working correctly?

Thank you.

 

[fin-bender]

Re: Power trim help please................

Would installing a tilt/trim guage help me?

What color wires should I look for in the wiring harness for a trim guage for a '98 115hp 2-stroke?

 

[RRitt]

Re: Power trim help please................

the mercury single ram system sold from about 1989 and on can handle trim up to 150HP. It has about a 2" bore and operates at 2500-3500psi which gives it about 8000lbs of thrust. The combination of high pressure and ATF fluid causes them to fail at a younger age than other systems. However, the single cylinder design makes them significantly easier to remove from boat for service and typically a lot less expensive to repair. Some 3 ram designs require removing engine from boat in order to put in a new trim motor.

The first third of the piston lift does not have a pressure limiting circuit. Your system should lift anything during this part of operation. About 1/3 up the cylinder wall there is a hole drilled where fluid can escape. The size of the spring holding down the seal for this channel determines which horsepower your trim system is supposed to fit. When you push down on the throttle the force of propeller pushes open the spring and the system will not rise any further. If your spring is too big and the motor too small you could possibly lift the prop out of the water while it is spinning.

when you reduce speed to idle, the prop stops pushing down on this spring and the engine will lift fully. It is normal for a running engine to only lift about 1/3 of the way under power and all the way at idle. If your engine does not even lift 1/3 of the way then your pump or trim limit spool needs servicing.

 

[fin-bender]

Re: Power trim help please................

Thanks! That gives me a much better understanding of how the system works. It sounds like "tilt" and "trim" are the same functionally, "trim" just limits the lift to the lower 1/3 while underway. After knowing that I think my motor is working just fine.

Can you tell me what color wires are used on a trim guage for my motor? I do have a few unused wires in the harness and I think I'd like to install one if the sending unit is already there.