Hank

Throttle Switch for Gear Position

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So, are you saying that you only move the switch rather than loosen the two clamps and move the entire mechanism up or down the throttle cable housing?

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15 minutes ago, MBDiagMan said:

So, are you saying that you only move the switch rather than loosen the two clamps and move the entire mechanism up or down the throttle cable housing?

That is correct, the adjustment is with the switch. 

Once clamped the switch bracket is securely anchored to the cable housing; two dimples in the bracket match two holes in the cable housing.

9AB30271-F993-421B-AC9D-A139FFDCACEA.jpeg

Edited by Culver LFA
Added photo showing holes in cable housing
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Expect that you are only moving the switch to fall in the hole...

It should activate somewhere below 12” of MP...

Any lower... you get very little warning of gear-up impending...

Any higher... you get an annoyance during descent....

Check the maintenance manual to see what it says about adjusting the switch...

Descending rapidly with the gear up... you either get to leave some throttle in to silence the alarm, or stick a finger in the hole to activate the gear switch...

There is no perfect MP setting for this... at MGTW the MP need is higher... lightly loaded the MP need is lower... but the switch is set in one place...

Consult your mechanic, and your MM, before using an ordinary PP... :)

Best regards,

-a-

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Nice pics gents!

The adjustable range is defined by the slot in the yellow painted sheet metal...

The actual push button of the switch.... is barely noticeable above the small wheel...

The button gets un-pushed as the wheel falls in the divot...

Unfortunately, I don’t see the actual push/pull control that runs down the center... in either of the pics that would show the divot... :)

PP thoughts only, not a mechanic...

Best regards,

-a-

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10 hours ago, carusoam said:

Unfortunately, I don’t see the actual push/pull control that runs down the center... in either of the pics that would show the divot... :)

PP thoughts only, not a mechanic...

Best regards,

-a-

Here ya go!

B29F164A-A613-4AF1-B44A-58009E99EB90.jpeg

43483CBD-247F-4E90-BF0D-663EDECE52FE.jpeg

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5 hours ago, MBDiagMan said:

What appears as yellow sheet metal I believe is circuit board material.

Technically I suppose you could call it that since the switch is mounted to it, but it is made of steel.

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1 hour ago, Culver LFA said:

Technically I suppose you could call it that since the switch is mounted to it, but it is made of steel.

I got a better look at it and you are correct.  It is steel, not circuit board.

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Sorry for two posts, but I couldn’t figure out how to edit the picture post to add text.

Fortunately, pulling the bottom radio gains good access.  If you look closely you can see that the switch is adjusted to the end of the slot.  I am hoping that pulling the top cowl will give me access to the other end of the throttle cable and I can adjust it there, then readjust the switch.

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15 minutes ago, MBDiagMan said:

Sorry for two posts, but I couldn’t figure out how to edit the picture post to add text.

Fortunately, pulling the bottom radio gains good access.  If you look closely you can see that the switch is adjusted to the end of the slot.  I am hoping that pulling the top cowl will give me access to the other end of the throttle cable and I can adjust it there, then readjust the switch.

The top cowl/avionics panel won’t help unless you have Go go gadget arms. You’ll have to reach up from under the panel with your other hand.

Having the seats out will help tremendously so you can at least be semi comfortable laying in the cabin floor with the trim wheel in your xyz while your left hand cramps up into a knot.

I love it so much I’m laying there now!

Here is a video for those that want to see what they are hearing behind the panel when they pull the throttle back.

Edited by Culver LFA
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I already have easy access to the gear horn switch after removing the bottom radio.  The problem is that there is no more room for adjustment.  The switch is as far rearward as it will go.  I am wondering if the cable can be adjusted on the engine end.  I also wonder if maybe the whole switch mechanism has been moved forward.  I read about the bumps that it seats on, but I might have to loosen it all up for some exploratory surgery.

Is anyone familiar with the engine end of the cable?  Is it adjustable and is it hard to access?

BTW when I talked about pulling the top cowl, I meant the panel above the engine to see what it will take to adjust the other end of the cable.

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2 hours ago, MBDiagMan said:

I already have easy access to the gear horn switch after removing the bottom radio.  The problem is that there is no more room for adjustment.  The switch is as far rearward as it will go.  I am wondering if the cable can be adjusted on the engine end.  I also wonder if maybe the whole switch mechanism has been moved forward.  I read about the bumps that it seats on, but I might have to loosen it all up for some exploratory surgery.

Is anyone familiar with the engine end of the cable?  Is it adjustable and is it hard to access?

BTW when I talked about pulling the top cowl, I meant the panel above the engine to see what it will take to adjust the other end of the cable.

OK, (looking at your picture and judging from the screws on the clamps holding the throttle housing to the bracket pointing in different directions, also the missing washers on all the fasteners), I think that someone has been in there and it is likely that  the problem is how your throttle switch/bracket is mounted to the cable.  I can't tell exactly what it is especially only seeing the back side of the bracket.  Can you get a picture from under the panel, down where the ram air cable is, pointing up towards the throttle cable/gear switch?

Some questions I have are:

1) The bracket seems to be installed in the correct orientation but it appears that the dimples are facing the wrong direction (out instead of in)?  Not sure how this is possible but something does not look correct there.

2) Can you determine if the throttle cable has been replaced before?  If so, is it a McFarlane, a modified Aircraft Spruce cable,  or what is it?  It is possible that the "window" for the switch was cut in the wrong location which has exceeded the limits of the switch adjustment (slots).

3) It's late and I have to think about this some more, but if you attempted to correct this by adjusting the throttle cable at the fuel injection servo as you suggested, you would be lengthening the cable end at the servo to move the cable back at the handle end.  This may then line up the throttle switch (which is currently adjusted to the limit)  but I think you will then run into an issue where the throttle knob will not be all the way to the panel when you go 100% wide open throttle.  This does not seem like a good solution to me, it's backwards thinking.  I think that the cable end at the fuel injection servo should be adjusted to length with the throttle knob all the way in for full travel first, then idle will fall where it will when the throttle is pulled all the way back, and finally the gear switch can then be adjusted.

Edited by Culver LFA

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Many thanks for the thoughtful response Culver.  I’m glad you mentioned the dimples.  With no experience beyond what I see and read, I thought maybe there were ball bearings under those nipples or somwthing.  The cable appears to be brand spanking new.

I am getting over the flu and have some other things that will keep me away from it for a few days.  I will continue to read about it here and give it thought before getting back to the hangar on Monday.

After your explanation I am even MORE hesitant to fool with the other end of the cable.  I don’t want to chance losing full throttle power.

BTW, I will get a picture from underneath as soon as I can.  I don’t remember seeing holes on the other side of the cable housing.

Thanks again.  I welcome all comments.

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The dimples apparently  are on the wrong side of the plate.  I took a picture before loosening the two clamps and moving the entire mechanism rearward, then readjusting the switch for the lowest power setting possible.

DA724452-F2E9-47BA-9CA1-1725EA898763.jpeg

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33 minutes ago, MBDiagMan said:

The dimples apparently  are on the wrong side of the plate.  I took a picture before loosening the two clamps and moving the entire mechanism rearward, then readjusting the switch for the lowest power setting possible.

DA724452-F2E9-47BA-9CA1-1725EA898763.jpeg

Actually your plate/bracket is correctly oriented, I found a picture to refresh my memory which I’ve attached.  There are pins installed on the other side that lock into the two holes in the cable housing, you should not be able to move the bracket fore/aft when the clamps are tightened.

If you have moved the bracket to adjust the switch then the bracket is no longer locked into the cable housing. The bracket needs to be installed correctly then the switch adjusted.

 

BD60E554-04CB-4C6C-82FE-2887E9C8A5D9.jpeg

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Thanks Culver!  I now feel comfortablw it’s the whole assembly.  We are headed out for the weekend.  When I get back I will disassemble the whole thing and examine.  I have all the tools necessary inside the plane so I should be able to get it all done without getting in and out to go to the toolbox.

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I got it together correctly and have the actuating at the very end of the opening in the cable housing.  It is actuating with the 5hrottle as far rearward as I can make it without changing the cable itself in some way.  I am at the worst stage of a very nasty cold so I was not ready to fly today.  The cable still travels rearward about 3/4” after the switch actuated.  I expect it will actuate at too high of a power setting.  Will keep you informed.

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I looked at it again this morning, but I still have a cold that is keeping me from flying it.  There is still about the same amount of rearward throttle travel as there was when it was not right.  I really believe it is still not right.  If not, is the cable position adjustable at the throttle body end?  Has anyone ever adjusted it.  I could not find anything in the service manual.

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I wonder if someone might have time to measure something for me.  My throttle cable can be pulled out 3/4” or more after the throttle switch is actuated.  How far can you pull out the throttle past the switch on your fuel injected Mooney.  You should be able to pull the cable out until you hear the switch click, then place a piece of tape on the cable at the friction wheel, then pull the cable all the way out and measure.  I don’t plan on setting mine by this measurement, but it would be great to have this as a reference if I have to pull the cowl and adjust the cable.

Thanks in advance for any help you can offer.

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Okay!  I removed the nose bowl and found the lower throttle linkage shaft hitting the oil pan.  Under the supervision of and inspection by my A&P I moved the bottom lever one tooth and now have proper throttle operation and the switch is actuating abou 1/4” before throttle is full rearward.  It is in the range of the switch, so I might have to tweak the switch slightly. 

I am very pleased with the whole thing and I now feel confident about the nose bowl removal and replacement procedure.

Thanks for the help!

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I flew her this morning and the throttle and gear horn are spot on!  Oh, the little things in life!

Now, the 345 doesn’t seem to be picking up a tower.  It’s always something.

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Interestingly to note, if nothing else - on a quick scan of the M20F POHs from '68 and '69, in '68 the "magic number" was 10 inchs of manifold pressure. For some reason (probably to give more warning), in the 1969 POH the number/setting was changed to 12 inches of maniford pressure.

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