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Issues with idle

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Old 08-12-2012, 06:37 PM
  #1
JohnP2
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Default Issues with idle

After putting a new throttle servo on my Losi 810, I noticed the wheels began tospin at idle- and by that it moved at a pretty good clip.

Below are the troubleshooting steps I've taken. This might be long, but want to provide details. Please noteIdo have experiencesetting throttle/brake linkage - but this has me stumped!

Please let me know what you think the issue could be.

1. I made sure the servo horn was on correctly with the servo at neutral.
2. I checked the carb opening. It was at 1mm (same it's been since I got the car).I lowered it to about .75 mm. Problem there was when I applied brakes it went to about .5 mm, causing the engine to stall.
3. Fixed #2 by adjusting idle stop with brakes applied. Problem with gap this small is engine is VERY hard to start. Still continued to move at a fast clip while engine idled. Determined ~.6 mmis smallest I can get to start car/allow engine to idle (again starting very difficult at to prime the hell out of it)..
4. Lowered idle trim down. All this did was apply some brakeage, which slowed the drive-train, stopping wheels from spinning.
5. Verified thottle and brakelink sets wereconfigured correctly.
6.Adjusted brake linkageso that the brake cam was not engaged when I applied via the tx, butwheel still spun. (I set it back after this test.)
7. By taking still pictures and using a CAD software, I determined there was~ .15 mm gap difference between the neutral and brake (could notseenwith naked eye).
8. Leaned the LSN in 1/8increments. While the engine had no problem idling (car was just moving) I wanted to rule out engine tuning problems.

I essentially configured it every imaginable way, and the bottom line is no matter how small I set the idle stop at (allowing car to start) the car movedabout 5-7 mph.

THEN....during one of the configurations where trim was at -5 (wheels not spinning as this moved brake cam enough to slow drive train) ), I noticed (with the car on a stand) that with when I barely applied throttle (< .5 inch) the engine did not rev, but tires began to spin. With that I concluded it HAS to be the clutch. Spring is either broken or weakened.

It seemsthe clutch is engaging the clutch bell at the lowest possible carb opening /no brake pressue possible. I've not looked at the clutch yet. It's a 2-shoe, so imagine it has a single spring going around both shoes (instead of individual spring)? I have an M2C three-shoe I've been meaning to pop-on, so this is my excuse to do so. :-) However, I want to ensure my troubleshooting steps are suffice.

Am I missing anything?

See attached for current carb opening. As noted, applying brakes moves it about .15mm (but you cannot tell with naked eye).
Thanks!

p.s. I can post a quck video showing the systoms if anyone feels that will help. I'm sure this is something the great minds on here can help solve. The good nes is that I will get a chance to leran something new. :-)
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Old 08-13-2012, 06:56 PM
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Default RE: Issues with idle

Ok, my thoughts

Sounds like the carby lever is not been pushed back into the idle screw when there is no throttle input.
Because u say it's dropping revs when u hit the brakes.

I would recomend setting the gap to 1mm and use the trim knob to trim the throttle down so it wont drop under braking.

Do it in 3 steps.
Setp 1
Set the idle opining to 1mm with full brakes applied

Step 2
Set the trim so the servo horn holds the spring slightly tighter to get the carby to the 1mm setting, double check it still holds it at 1mm in the neutral position and does not open slightly. Then move the collet up on the throttle linkage so there is a small gap between it and the servo horn. re set end points

Step 3
Adjust the brakes, they might need to be loosened


If the car still moves with a low idle speed then yeah u might need a new clutch spring or the clutch bell needs cleaning on the wearing surface
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Old 08-14-2012, 05:16 PM
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Default RE: Issues with idle

Thanks, man, You might be on to something here.
"Sounds carby lever is not been pushed back into the idle screw when there is no throttle input."

This is something I have not diagnosed (or did and not know it). Unsure what you mean by the "carby lever"

Another odd symptom I had, is when I had trim set all the way down so that clutch did not engage, when I (barely) pressed the throttle trigger on my tx the clutch would engage....but the engine did NOT rev.

I'm going to post a video of the symptoms to help you and others better troubleshoot. Will post it tomorrow (Wed). If you (or anyone on here) can help me rectify this, I'll buy you a trophy). ;-) You all know I am apt to learning anything - and this one has me stumped.

Thanks again!
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Old 08-14-2012, 07:37 PM
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Default RE: Issues with idle


Quote:
ORIGINAL: JohnP2

Thanks, man, You might be on to something here.
"Sounds carby lever is not been pushed back into the idle screw when there is no throttle input."

This is something I have not diagnosed (or did and not know it). Unsure what you mean by the "carby lever"

Another odd symptom I had, is when I had trim set all the way down so that clutch did not engage, when I (barely) pressed the throttle trigger on my tx the clutch would engage....but the engine did NOT rev.

I'm going to post a video of the symptoms to help you and others better troubleshoot. Will post it tomorrow (Wed). If you (or anyone on here) can help me rectify this, I'll buy you a trophy). ;-) You all know I am apt to learning anything - and this one has me stumped.

Thanks again!
Your answer is blowing in the wind. Or should I say inthe General Discussion Forum.
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Old 08-14-2012, 08:05 PM
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Default RE: Issues with idle

Seems like this is getting waaay over complicated, you installed a servo and now it's acting weird...
The horn is at a different spot, because it's a new servo, and that's causing the linkage to be in a different spot.
Sounds like a simple radio trim setting to me, but that's just me.
The only variable is the new servo, yes?
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Old 08-15-2012, 11:11 AM
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Default RE: Issues with idle


Quote:
ORIGINAL: SLAYERDUDE

Seems like this is getting waaay over complicated, you installed a servo and now it's acting weird...
The horn is at a different spot, because it's a new servo, and that's causing the linkage to be in a different spot.
Sounds like a simple radio trim setting to me, but that's just me.
The only variable is the new servo, yes?
I agree...it sounds simple, but as noted I've set the servo horn on correctly (among other things). I'm uploading a video on it now so you guys can SEE what I'm talking about.

I'm also going to inspect the clutch shoes this evening. Thanks
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Old 08-15-2012, 11:35 AM
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Default RE: Issues with idle

As soon as I started to take off the clutch bell...I found the issue (what I suspected). I wanted to rule out throttle settings first, of course.

Below is my problem. ;-) Either that or the fact I put the heat gun on the clutch bell for three minutes to loosen the clutch bell screw's loctite snapped the spring....but based on the symptoms don't see how that can be it.

Now I have an excuse to throw on the M2C three-shoe clutch I have lying around. ;-)
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Old 08-15-2012, 12:34 PM
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Default RE: Issues with idle

Don't ya hate it when some crazy problem happens when you made a different repair!
Glad you found it!
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Old 08-15-2012, 12:55 PM
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Default RE: Issues with idle


Quote:
ORIGINAL: JohnP2

As soon as I started to take off the clutch bell...I found the issue (what I suspected). I wanted to rule out throttle settings first, of course.

Below is my problem. ;-) Either that or the fact I put the heat gun on the clutch bell for three minutes to loosen the clutch bell screw's loctite snapped the spring....but based on the symptoms don't see how that can be it.

Now I have an excuse to throw on the M2C three-shoe clutch I have lying around. ;-)
I'm surprised it took this long for your clutch spring to break... mine broke after about 8 tanks.
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Old 08-15-2012, 04:06 PM
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Default RE: Issues with idle


Quote:
ORIGINAL: nitroexpress


Quote:
ORIGINAL: JohnP2

Thanks, man, You might be on to something here.
''Sounds carby lever is not been pushed back into the idle screw when there is no throttle input. ''

This is something I have not diagnosed (or did and not know it). Unsure what you mean by the ''carby lever''

Another odd symptom I had, is when I had trim set all the way down so that clutch did not engage, when I (barely) pressed the throttle trigger on my tx the clutch would engage....but the engine did NOT rev.

I'm going to post a video of the symptoms to help you and others better troubleshoot. Will post it tomorrow (Wed). If you (or anyone on here) can help me rectify this, I'll buy you a trophy). ;-) You all know I am apt to learning anything - and this one has me stumped.

Thanks again!
Your answer is blowing in the wind. Or should I say in the General Discussion Forum. [img][/img]

what does that mean????

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Old 08-15-2012, 04:13 PM
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Default RE: Issues with idle




Quote:
ORIGINAL: SLAYERDUDE



Don't ya hate it when some crazy problem happens when you made a different repair!
Glad you found it!
Yep!This is what I found so confusing. I KNEW I was setting the throttle linkage up correctly, so figured it had to be the clutch- but wanted to check with experts as yourself to ensure I was not missing anything as I ruled out everything. I spent an entire afternoon going through this. I've set the throttle linkage (either with a new servo or putting engine back on my vehicles) at leat 20 times....but this was great as I took every the entire assembly completely apart and modified the springs/grub nuts every way I could think of. I learned a lot (especially about brakes). ;-)
Quote:
ORIGINAL: proanti1
I'm surprised it took this long for your clutch spring to break... mine broke after about 8 tanks.
Ha! I guess I got the most out of it. Thanks to you I have a nice M2C clutch I ordered way back....I'm popping that on first thing Saturday morning. Can't wait!

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Old 08-15-2012, 04:17 PM
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Default RE: Issues with idle

Carby lever,carby slide ballend, thrrottle linkage, etc
call it what u want.

I think the OP needs to address the problem of it droping RPM under braking. Ive posted very basic instructions on ho to do it correctly....

Yeah sure he could just adjust the trim like some people have said, but thats going to cause a dead spot just of netural where the servo will move but the carby slide wont., why would people even recomend that? If the OP adjusts the linkages like I said in the 1st post there will be no problems.

OP- getthe clutch sorted out, and dont forget to adjust the throttle return spring correctly
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Old 08-15-2012, 04:21 PM
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Default RE: Issues with idle


Quote:
ORIGINAL: phmaximus

Yeah sure he could just adjust the trim like some people have said, but thats going to cause a dead spot just of netural where the servo will move but the carby slide wont.,
Agreed, sir. I rarely use trim and understand it is not to mask overriding issues. Thanks to you I spent a lot of time learning about my throttle spring and will ensure it is set correctly once I pop on the new clutch.
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Old 08-16-2012, 09:16 AM
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Default RE: Issues with idle

Or you can just bend a hook back on the spring and put it back on there...........cost zero works like it did before.
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