Getting access to throttle lever TRIM SWITCH (Mercury 50 ELPTO 2003)

Hi all.

Throttle arm TRIM SWITCH is a bit ropey - the one on the cowl works fine, but the 'down' on the throttle arm only intermittently. Also, it 'feels' a bit sloppy in action, and not as crisp as it once was.

So, I want the fellow out!

Except I don;t know how to get access to it...

Any ideas, please?

See photos: the upper section of the throttle arm has a one-piece plastic cover which I can just about partly prise up near its bottom as it goes around the arm and you can get to its ends where it meets the red 'neutral lock' lever, but I'm loath to prise it any further, and I cannot see how it can lift off the top handle part as it seems to fully cover this, top and bottom.

Help!

Ok, job done.

You need to remove the whole control unit - three nuts - from your console (the bolts pass through the control unit from the outside with the nuts inside the console).

Behind the removed unit, in the centre, you'll find the recessed head of a bolt which passes through the unit and goes into the handle and secures it.

Prise off that square decorative 'Mercury' cover on the outside of the gear lever - use a small flat-bladed screwdriver around the edges. You'll see the ends of the switch wires as they disappear into the unit, and you'll also see the tip of the large bolt mentioned above.

Undo that bolt and the whole handle will come off. It'll be restrained by the cable tho'.

The red 'neutral lock' lever is held in place with a small bridging clip and two screws. When that red lever is removed, you should get access to the back of the trim switch. (Watch out - there will be a spring inside that red handle somewhere...!)

The back covers of the control unit are held on by 5 screws - 3 in the main part and two hold a narrower cover along the bottom. (The lower cover cannot be removed by itself as the top cover goes over a cranked section in one corner!)

Once the covers are removed, you should have access to all the wiring 'push' terminals so will be able to remove the switch complete with short length of cable.

Having now completed the job (actually finding that the wires were ok...), I'll add a couple of more points in case anyone else is doing this kind of job.

Ensure the gear/throttle lever is in the 'neutral' position before you remove the back covers (main cover has three screws, the lower one 2). I'm not sure how important this actually, is, but it's complex inside that unit so best to not add any unwanted variables!

Ok, the bottom panel will not come off by itself - incredibly, the top cover overlaps a segment in the corner, so the top cover has to come off (or be loosened a great deal) before the bottom cover comes off!

See the throttle 'fast idle' lever? Leave that in place when you remove the top cover - it'll come away with that cover, still attached to it. There's a very good reason why I'm suggesting this - the throttle lever and the main gear/throttle control are 'linked' via a small round spring-loaded bearing wheel (around 8mm dia) which ensures that the gear lever cannot be engaged when the engine is 'fast-idled' (you are probably aware of this feature). This wee bearing wheel is mounted to the back of the cover. If you remove the fast idle lever from the casing first, you will leave behind the fast-idle mechanism (a metal wheel around 50mm dia with a wee pinion sticking out the back) which does this safety job. Once you remove the cover - leaving this mechanism behind - the wee bearing wheel I mentioned before will move position (as it's spring-loaded) and you won't be able to simply replace that cover again 'cos the wee bearing will be in the way!

But, it ain't a problem if this happens. Simply refit the whole idle lever mechanism on to the back cover first (ie - the round disc on the back and the lever on the front - two screws secure them together). Push that wee round spring-loaded bearing out of the way as you position the round wheel. Screw on the idle lever. That wee bearing is now secure in its correct place - pushing against the outside edge of the fast idle disc. (This will all be obvious when you look at it - honestly...)

With the fast idle mech now fitted on to the back cover, you'll now be able to refit the cover - but make sure that the pin on the fast-idle wheel is in roughly the right place to engage with the slotted lever inside the control box; a wee bit of fast-idle lever wobbling will make it locate.

Sadly I couldn't take photos as my hands were thoroughly covered in grease (I gave the insides a liberal coating) but there are exploded diagrams out there and I'll happily guide peeps through this issue if needed.

Having a similar issue, sounds fairly involved.

Cre73 said:

Having a similar issue, sounds fairly involved.

Click to expand...

Yes. And no...

You don't have to be an engineer or mechanic, but it helps if you aren't spooked by opening up a box of weird, hard-to-follow mechanisms.

The thing is, tho', you don't have to touch that stuff.

The job essentially comes down to: (1) Remove the whole unit from the console (but leave all the cables attached), (2) Undo that single large bolt to remove the throttle lever, (3) Undo the two screws that hold a small metal plate which holds the red 'neutral-lock' control in place, and remove it, (4) Lay the unit flat on a suitable surface - small table, stool, etc - and undo the 5 screws that hold on the back cover.

That's it - you now have full access to everything. Don't disturb any of the mechs inside, don't move the cables, don't do anything you don't want to...

Have something heavy to sit on the cables around a foot after they exit the unit, and that'll hold the whole unit flat and steady for you to work on - the stiff cables can otherwise move the unit around in ways you don't want!

(I didn't actually remove the switch in the end as I found it to be working fine, so I'm guessing it's held in place in an obvious way. I did give all the mechs a darned good greasing, tho' - clearly it was the first time it was opened in ~15 years - and it felt better afterwards.)