Alpha I gen I Mercruiser trim question

[Augoose]

I have recently had a new trim sending unit / limit switch kit put in my boat. The repair guys seemingly tried to set it up to the stock measurements according the manual (measuring the distance on the hydraulic arm) however, I've got two issues I'm contending with that they didn't tell me about.

When I took the boat out, I found that I did not have the proper range of travel for the trim. It would of course go down all the way but the only way to trim it up more than an inch or two from full down position, was to touch the trailer button for a few seconds to raise it up.

Secondly, when I went to just simply adjust the limit switch, I noticed I was out of room to adjust it when I spun it counter clockwise. After several minutes I noticed that the original bottom screw hold which locks in the limit switch had been broken off, ground down, and a new hole threaded in just to the left of the original. This didn't allow for enough adjustment so I couldn't raise the unit more than a couple of inches. So I did what the shop should have - drill out the broken stud and mounted back in it's original location.

Now my third problem is that when I went to measure the hydraulic arm to set the "up" position, I discovered my hydraulic arms are not the original equipment and what should have been a good up position was no where near the 21" or so that the factory calls for.

So.....does anyone have any other technique that I can use to measure a safe "up" position so I can set the limit switch? Right now I set it at a conservative "up" position so I don't over stress the U-joints.

Could someone measure their Alpha I and see how far below "trailer position" the "up" position is when using the trim switch? Maybe use two known points of reference and measure "trailer" vs "up".

Any other suggestions? Maybe measuring the angle from three known points?

Thanks for any help!

 

[Don S]

Re: Alpha I gen I Mercruiser trim question

It doesn't matter what kind of trim rams you have, the distance from the centerline of the front pin and the aft pin are what you go by. and 21 3/4" is the max trim for that drive, or any 1, R, MR, or Alpha I for that matter.

The problem with your limit switch is the fact that they only redrilled and tapped one hole when the screw broke off. (Common problem, especially in salt water)
What I do if I break one screw is drill 2 holes, then you keep the full range of adjustment. Like the drawing below. IF I broke the upper screw (a) I would drill and tap a new hole at (b). Then do the same on the lower screw. Now you have full adjustment.

 

[Augoose]

Re: Alpha I gen I Mercruiser trim question

and 21 3/4" is the max trim for that drive, or any 1, R, MR, or Alpha I for that matter

Thanks for the help Don.
Regarding the rams, I was thinking about exactly that today while out for a test run and the fact that part of what I typed didn't make sense. No matter the brand of rams, the mounting bolts will always be in the same place.

Also, I realized that this boat is quite different from the 2001 stingray I was used to. I was expecting the trim button to allow the lower unit to come pretty far up and close to the trailer position, so if you were in the shallows, you could still slowly manuever about. However, I just read about the "safe range" for the trim and now it makes sense that my ram's need to stop at 21 3/4". When I set the limit switch to that position and tried to raise the lower unit, it hardly moved at all when it moved from the lowest position and then stopped at 21 3/4". Is this right? Should I not have a whole lot of range of motion when raising and lowering the unit with the trim button?

Is this "safe range" limited in older boats such as mine (1989) and different from newer boats such as a 2001 Stingray? I recall a wide range of motion for the trim button on my dad's Stingray, using it to idle through shallows and such.

Lastly and unknowingly, I operated my boat today on a test run in shallows at a position halfway between trailer and 21 3/4" not knowing what I know now- however it was under low RPM'S and right about idle speed. Did I likely damage the u-joints?....

Thanks again for the help