Idle microswitch?

[John U]

I just finished the VOD reassembly and I notice that at idle, the idle microswitch does not get pushed far enough to engage. I adjusted the striker bolt a little, but it seems the problem is that the throttle does not quite return to idle when released. It does return to idle when I give it a little help with the push of a finger. Is there a method for adjusting and or lubricating the throttle assembly so it returns all the way to idle on its own?

thanks
John

[opethmike]

Yeah, its pretty easy - just take apart the throttle spool. You just need to pop out a little circlip that is on top of it, then the rest just lifts apart.

Lubricate the stud that the spool rides on, as well as both springs.

[outatym2001]

There are a grand total of four springs tied to the Accelerator Pedal. Please remember when increasing the tension (tightness) it will also make the accelerator pedal firmer.
One spring is directly above the accelerator pedal and can not be adjusted.
Two springs are on the Throttle Control item 31 on page 1/4/1.
One spring is connected to the Lever item 23 on page 1/4/1. That spring on the Lever is not illustrated for some reason.
You would have to remove the Throttle Valve Assembly item 10 on page 1/4/1 in order to remove the spring and make it a little tighter like I did some time ago.

To remove the Throttle Valve Assembly it helps to have a hex key that is over 4” (10 cm) long.

I did what opethmike suggested and that Throttle Control spool is suprisingly dirty underneath and I lubricated it with white lithium grease since that’s what I had at the time.

[David T]

You may also find a lot of play in the ends of the quadrant link. It is on a left hand-right hand threaded link so you can get a very precise adjustment. You need it to be on the "long" side so it can push the throttle arm all the way to set the micro switch at idle. You might also want to lubricate the throttle cable as per the recall. Check that the pedal linkage is not bent. When you step all the way down on the accelerator pedal you should trip the WOT switch. There should be no play or "stickiness" in the throttle and the carpet and floor mat must NOT interfere with the pedal.
David Teitelbaum

[John U]

looks like there is some play in the throttle arm....if I shorten the arm a couple of mm it looks like it may help...funny thing is that it operates properly with the engine off but seems to encounter a little more resistance with the engine running.
WOT switch trips properly.
I lubed the springs and throttle spool.

[opethmike]

When its running, there is vacuum, that's the difference :)

[Bitsyncmaster]

Make sure your switch is set to close sooner than full closed. I found out designing my idle ECU if the advance stays on below 1200 RPM the idle will not drop past that on some engines with not load and warmed up.

That makes you think the throttle is not fully closing.

Advance increases the idle RPM about 500 RPM if the idle motor is already fully closed.

[John U]

it looks like there is play in the throttle arm and shortening it a bit might help my situation (I think)
I can set the microswitch to close earlier, but it seems that with the play, the throttle does not quite close all the way and idles at 1000rpm. If i push on the microswitch arm (with the microswitch already engaged) the throttle moves slightly (1mm) and the rpms come down around 750

[Bitsyncmaster]

it looks like there is play in the throttle arm and shortening it a bit might help my situation (I think)
I can set the microswitch to close earlier, but it seems that with the play, the throttle does not quite close all the way and idles at 1000rpm. If i push on the microswitch arm (with the microswitch already engaged) the throttle moves slightly (1mm) and the rpms come down around 750

My "guess" is adjusting the switch to engage sooner may fix your problem. It's real quick to test this.

Your other option is to add more springs or get a new throttle assembly. Another option is to get John's switch which others have claimed helped with this problem.

[John U]

My "guess" is adjusting the switch to engage sooner may fix your problem. It's real quick to test this.


do you mean adjusting the bolt that engages the microswitch? I have adjusted it to engage very early, but until i push the throttle arm with my finger, the rpms won't come down...when i push the throttle arm closed, the throttle spool isn't moving, just the arm...pushing it just takes up that little bit of play that seems to prevent the full closure of the throttle

[Bitsyncmaster]

do you mean adjusting the bolt that engages the microswitch? I have adjusted it to engage very early, but until i push the throttle arm with my finger, the rpms won't come down...when i push the throttle arm closed, the throttle spool isn't moving, just the arm...pushing it just takes up that little bit of play that seems to prevent the full closure of the throttle

Yes, turn it clockwise a little and see if that helps.

[82DMC12]

My "guess" is adjusting the switch to engage sooner may fix your problem. It's real quick to test this.

Your other option is to add more springs or get a new throttle assembly. Another option is to get John's switch which others have claimed helped with this problem.

Which switch are you talking about (John's switch)?

Andy

[Bitsyncmaster]

Which switch are you talking about (John's switch)?

Andy

Special T has a switch that takes less force to engage. That gives the throttle plates a little more closing force.

[John U]

no, the original microswitch

yes I have adjusted it many different ways to the point where it was being engaged way early, but the rpms aren't coming down until I physically close the throttle all the way by pushing on the throttle pushrod with my finger

[Bitsyncmaster]

no, the original microswitch

yes I have adjusted it many different ways to the point where it was being engaged way early, but the rpms aren't coming down until I physically close the throttle all the way by pushing on the throttle pushrod with my finger

OK. Then my guess was wrong.

Maybe you can post a photo of how the spool and arm sits in the idle position. Then other owners without the problem can comment on the adjustment.

[John U]

problem solved....I shortened the throttle pushrod by turning one end twice. it works perfectly now. the throttle fully closes, and has no problem engaging the microswitch! There was a little too much play in the ends. Shortening the rod took up the slack.

[David T]

At your annual service it should be added to put a drop of oil into each quadrant link end. Along with lubricating the angle drive, inspecting the C/V boots, etc, etc.
David Teitelbaum