Hey guys, I have a 78 Sleekcraft with a Mercruiser 260. Well, 2 weeks ago, the trim pump quit working. No, it's not the solenoid, that still clicks fine, and I tried jumping the motor with a healthy piece of wire, no dice. It looked like this:


Anyway, wanting to hit the water this weekend, I picked this up locally:

Same # of wires, same colors wires, and only 2 ports, one must be high pressure and one low pressure, right?

Well, I wired it all up so it was identical to my original one, and it works! Sort of. It trims at like 4x speed, and when I trimmed down, it blew the seals on the reverse trim lockout switch thing. Why did it do this? I don't understand, a trim pump should be a trim pump, right? Is it just moving way more fluid than the old one? If so, wtf kind of trim rams did that have? I don't understand what I did wrong here.

Hydraulic line reversed
Old pump is designed for 2700 to 3500 psi up and 550 to 800 down.

Newer Oildyne pump 2200 to 2600 up and 400 to 600 down

But it isn't reversed, the switches function as normal. It's just 4x the speed and blow seals out.

Pressures are comparable so could be the old pump was low on pressure and seals might have blown sooner if pressures were up to spec, but other than that I don't know