Throttle lever slack take up

[Horse46 512]

As I'm new to all things WH I may be asking stupid questions but please bear with me.

What I want to know is, can the motor be over revved so to speak if the throttle lever is pushed to its max position?

Why I ask this is, the throttle lever had about an inch of movement before it had any effect on the engine. So what I did was take up the slack, not all but most of it, so when the lever is moved now it actually raises the revs with only a bit of throttle. So now if someone did raise it to its max position would it cause damage by over reving?

I guess what I'm asking is, is there a pre set amount of slack left for a reason ?

[gwest_ca-(File Mod) 10,488]

Yes they can be over revved but don't think the amount of cable slack controlled it. On the C-Series there is a L-bracket bolted on top of the valve cover that can be positioned to limit the amount of throttle applied. What model of tractor and engine?

 

Garry

[Horse46 512]

Hey Garry

It's a C-101 Model No. K241AS.

[gwest_ca-(File Mod) 10,488]

Service manual

 

Page 6-31 and Figure 6-48 shows the high speed stop which is slightly different than what I have seen.

 

Garry

[PaulC 341]

i just bought laser tachometer to check this very thing. its a neat little tool and i was able to get my idle and full throttle rpms right where they should be. i believe for most of these engines idle should be 1200 and full should be 3400. you would want to double check that to your engine by downloading the manuals for it off of our great site here in the manuals section

 

i bought my laser tach from amazon and it was only 20 bucks, stick a little piece of reflective tape(which it comes with) to the flywheel screen or pto and point the laser at it with the engine running... piece of cake.

[Horse46 512]

I have been trying to get my horse to run nice today, so this is where I'm at right now.

She starts ok, takes a few seconds for the fuel to arrive but not an issue.

I use a little throttle and full choke but the choke and throttle can be wound off fairly quick.

I've got it ticking over as low as I can without it cutting out or stuttering ( sounds lovely ) and at higher revs it all good.

What I'm not happy with is trying to get from low revs up to medium revs and back to tick over.

1st trying to get a smooth transition from tick over, what's happening feels like it's going to cut out but then the revs come up and it's ok, what could be causing that?

2nd when I return to tick over it seems it doesn't want to drop all the way, it sits just above tick over and I have put a little pressure directly to the control arm or linkage on the carb to get it back to tick over.

I'm not a mechanic but have a fair idea what I'm doing, so if you guys have any tips please fire away.

Oh also I noted that when I'm trying to get the revs up, when it faulters there is a little whiff of black smoke from the exhaust and when I drop the revs quickly it pops and sometimes bangs a back fire, not all the time though.

[Horse46 512]

Service manual

 

Page 6-31 and Figure 6-48 shows the high speed stop which is slightly different than what I have seen.

 

Garry

Mine doesn't have that stop, my fitting is flat?

[boovuc 1,090]

Hi Horse46!

Popping and back firing when dropping RPM's and blowing some smoke on a low RPM to full throttle increase can be somewhat expected on a 30+ year old engine though my first inclination of back-firing and popping is too lean of a fuel mixture. Look at your governor control bracket carefully to see if the high speed stop may have been removed at some time by a puller or "nut" that just wanted more engine RPM.

Also be very careful running your motor at too low of an idle. I have seen the YouTube videos of the guys that like to show how "smooth" their Kohlers run but there is no way those oil splash systems are getting enough lubrication to the top of the engine. They aren't a hit & miss engine!  They need minimum RPM's at idle even with a synthetic oil being used. 

[rick 215]

Please- for your engines sake- at least 1200 RPM at idle. Cooling and lubrication are critical to the longevity of an air cooled engine. At proper idle speed, the idle mixture screw should be adjusted midway between the points where the engine starts to run rough on the lean and rich side. All else being in good repair, the engine should pick up speed smoothly. Now the engines are not as finely controlled as a car, and were not calibrated for a rapid pick up. Some do, some don't. By the way, the high speed is adjusted the same way, screw adjusted mid between rich and lean roughness. Some slight adjustment may be needed, be sure to get the engine to running temperature before adjusting. A high or low carburetor float will make a big difference, too. The Kohler engine manual is available for download, maybe even on this site.

[Horse46 512]

Hi Horse46!

Popping and back firing when dropping RPM's and blowing some smoke on a low RPM to full throttle increase can be somewhat expected on a 30+ year old engine though my first inclination of back-firing and popping is too lean of a fuel mixture. Look at your governor control bracket carefully to see if the high speed stop may have been removed at some time by a puller or "nut" that just wanted more engine RPM.

Also be very careful running your motor at too low of an idle. I have seen the YouTube videos of the guys that like to show how "smooth" their Kohlers run but there is no way those oil splash systems are getting enough lubrication to the top of the engine. They aren't a hit & miss engine!  They need minimum RPM's at idle even with a synthetic oil being used.

Thanks for the advice, this is my first Horse so it's a steep learning curve. I have owned a few Harley's over the years and I do like the slow tick over so thanks for the advice on the lubrication I wouldn't have thought of that.

I wasn't sure about the speed of pick up or the speed of return to idle so again good advice.

Definitely no high speed stop, however I do have a mechanical sympathy so it won't be getting ragged by me.

I will have a mess with the mixture to see if I can improve anything however apart from what I said she sounds pretty good.

[Horse46 512]

Please- for your engines sake- at least 1200 RPM at idle. Cooling and lubrication are critical to the longevity of an air cooled engine. At proper idle speed, the idle mixture screw should be adjusted midway between the points where the engine starts to run rough on the lean and rich side. All else being in good repair, the engine should pick up speed smoothly. Now the engines are not as finely controlled as a car, and were not calibrated for a rapid pick up. Some do, some don't. By the way, the high speed is adjusted the same way, screw adjusted mid between rich and lean roughness. Some slight adjustment may be needed, be sure to get the engine to running temperature before adjusting. A high or low carburetor float will make a big difference, too. The Kohler engine manual is available for download, maybe even on this site.

Again thanks for the great advice on low idle lubrication, I will have a look at fuelling at low an high revs to get it as good as I can..

Q. What do you mean by a high or low carburettor float, you lost me there?

[Horse46 512]

Ok after much messing around I've managed to upload a video to the tube of my engine running, showing the problem

New clip

Edited November 11, 2014 by Horse46

[Horse46 512]

I have added a better clip of the engine running, hopefully showing tick over speed and then the hesitation on trying to increase the speed, and then showing having to touch the control arm to get the revs to drop back to tick over.

Is the tick over to low? I think it maybe a bit having considered the lubrication of the top end?

[Horse46 512]

Just reading another topic on an engine running rough, and fuel was mentioned but more to the point fuel additive. I live in the uk and our fuel is 95 octane rating, should I be adding anything to my fuel or is it just because of the ethernol? You guys have over the pond.

[Horse46 512]

Any view from the engine gurus on here on my engine running?

[jrc0528 20]

It may help if you take a video showing the operation of governor linkage to the carb during both the acceleration and deceleration.  Sounds to me to be too lean at idle, causing it to stumble on throttle application.  An audio analysis shows your idle speed is just a tad low at around 1000 RPM vs 1200, but that's close enough it shouldn't cause you any grief.  The high speed is a bit harder to tell, but appears to be right around 3400RPM.  

 

I'd try slowly opening the idle mix screw and accelerating the motor perhaps an 1/8th turn at a time and see if it helps.  A lean idle may also cause it to not come back down to idle straight away, although even my horse does this a bit.   

 

Another idea is to check your throttle shaft bushings in the carburetor.  I know there's a few threads here somewhere on the topic; with age these bushings wear out and will allow the throttle shaft to have excessive play (is it loose if you grab the top end of the shaft and wiggle it?) and also allows air to enter the carb through this bore.  The extra air admittance makes properly tuning the jets neigh impossible.  If the wear isn't too excessive you can find rebuild kits to replace the bushings and get it working properly again.

[Horse46 512]

I had a chance to look at the tractor today, I got her running at a nice temp and tried to adjust the idle mixture, after raising the tick over slightly.

I have to be honest it didn't make one iota of difference, I screwed it in a few turns and out from where it was but made no difference what so ever???

This is the carb model on my horse.

I did note though that the throttle arm where it goes into the carb has a bit of play in it, side to side and up an down. Would this cause the engine not want to return to tick over ?

[jrc0528 20]

That play, in particular the side-to-side play, is the symptom of the worn out bushings.  IIRC, there may be a small felt washer where the shaft leaves the carb body.  Regardless, try placing a drop of good thick oil (140wt gear lube should work, chainsaw bar&chain oil would be much better, or even a dab of grease smeared clear around the shaft) on the shaft where it exits the carb while the engine is idling.  If you hear a response from the engine than you have an air leak significant enough to cause tuning trouble.  This bushing wear is quite common on these K series engines.  

 

 

I'd suggest you have a look at this site as it has literally everything you'll ever need to know about these Carter carbs!  http://gardentractorpullingtips.com/carbfuel.htm