Re: Trim/Tilt problem
there are two types of motors -
those with permanent magnets and those with electro-magnets.
if you reverse the wires on a magnet motor then it will spin the other way. that is why 2wire motors do not have a ground. you simply flip the wires to trim down.
if you reverse the wires on an electromagent motor then it spins in same direction. that's because you are reverseing both the armature magnet and the frame magnet. the two reversals cancel each other out. So the 3w motor actaully has two sets of electromagnets (called field coils). One is wound clockwise (blue) and the other is wound counter-clockwise (green). The black wire is a comon ground for both windings. If you put power on the blue wire then trim goes up. If you oput power on the green wire then trim goes down. If you put power on both wires then it gets hot and bursts into flames. If you ground blue or green then you partially energize both coils (like poking a second hole in a bucket full of electrons) and it gets hot & melts something.
the difference between 2w and 3w harness is whether or not there is a common ground. 2w motors do not have a ground. they just have polarity and flipped polarity. this is good for motor and electrical because it is easier to wire, and more tolerant of terminal corrosion. The wiring is cheaper because you do not have to use big heavy wires and terminals to avoid voltage loss and the relays can be $3 headlight thingys instead of $30 starter solenoids. However ... parker hannafin put out a champ of a 3w motor during the 90's. Built like a tank. last forever. stainless steel frame bolts on every corner with a double seals. heavy duty lower bearing and lip seal. quad brushes instead of two and 50% larger contact area per brush. It was built to the same type of standards used on industrial and military stuff. I think it's because it was one of their first recreational trim motors and they just went with their industrial roots. So maybe its worth the wiring hassle if you have an original parker hanafin (oildyne) 3w. However, the chinese stuff is cr*p and the aftermarket stuff is not built to same standards. Your motor that went bad after 2Y is prolly chinese? Wow, what a surprise. chinese stuff that broke.
back to 2w. 2w motors do not have a common ground. As it turns out, magnetic fields create electricity in nearby metal. So the trim motor magnet was causing any nearby iron to put out electricity. Which was causing the aluminum to pit and corrode very quickly. Nobody ever noticed this with 3w motors because the motor has common ground. Whenever you use a 2w motor you need to install a ground strap. Better yet - a ground strap made from SS that goes directly between an anode and the trim system. That is what the little silver wire is and does on mercury trim.
once working the motor spins a pump. the pump does great with fluid but doesn't work with air. if there is not enough oil then system raises to a level and stops. inside the pump are tiny little valves, gates, and controls that control the flow of fluid. As soon as the motor stopps spinning they sense it and lock the system. If you engine does not stay in position then it is almost always these little valves. Boy, they are hard to fix. very hard to fix.
the ram is just a ram. a hollow tube with a piuston. pump fluid in and piston goes up. pump fluid back into reservoir and poiston goes down. (its actually a tiny bit more complicated but that model works well enough). the piston rings are big fat pieces of rubber. they eventually go bad but the pump almost always goes first. what does happen is a design flaw in the mercury system exagerates a weakness inherent in all marine trim. Water gets back into the system by hitching a ride on piston shaft when you lower engine. The mercury single ram design (1987-2010) has a steel valve at the lowest point in system. During the off season water collects there and rusts up the valve. You need to keep that top center seal in tip-top shape. How long your system lasts is directly related to how much you use your engine because if you don't ever use your engine then you don't ever get water. For the average mercury 35-120HP boater it is 15years.
well, that's about all I know about mercury trim that fits on this page. I haven't dug into the 3 ram systems yet. they are sure to be an extension of the single ram though. same engineers for both. hope it helps.
