Throttle Trim Switch for 1993 Mercury 150 hp Outboard

[Chip S]

About a month ago my outboard engine trimmed up on its own. I replaced the trim solenoids and thought I fixed the problem. Today the engine again trimmed up on its own. I now think the throttle trim switch might be bad. The replacement trim switch part numbers I found are:

87-18286A43
87-16991A1
87-18286A2
87-18286A26

Does anyone know if one of these is the correct part number? Also, any advice regarding how to replace the trim switch? Are there any tricks that will make it easier?

 

[JHornsby3]

I was thumbing through the manual last night. It looks like the end where the switches are just "pops" out and the switches can be replaced.

Ok, I pulled it again. The bezel around the switch pops off and the switch can be replaced from there.

I assume you have the single control. And I am looking at the dual paperwork from 1992. As for part numbers, this paperwork has no numbers or exploded view. The single looked the same as mine when I was trying to find the cover numbers. Only one stick verses two.

 

[Chip S]

Update on this project. When I turned the battery switch on today the engine started trimming up on its own. I turned the battery switch off and disconnected the throttle trim switch from the engine wiring. When I turned the battery switch on again the engine started trimming up again on its own. I turned the battery switch off and disconnected the engine mounted trim switch from the engine wiring. When I turned the battery switch back on nothing happened. The engine mounted trim switch is bad.

The trim switch that was on the engine has been replaced by a more modern part. The part numbers for the current parts are:

Trim switch: 87-8M0042301
Retainer: 8M0032848

Once I get the new parts installed I'll provide an update regarding how difficult it was.

 

[Chip S]

I replaced the trim switch and retainer yesterday. It took about 1 hour. Very easy to do. Remove the copper retainer by sliding it up, then pull out the old switch housing. Put the new switch housing in and slide down the new retainer. The electrical connections were snug, but I got them connected by jiggling the two parts as I pushed them together. Everything is now working fine. Hopefully the new switch will last as long as the old switch (28 years).