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John Deere L120 With Briggs 20hp V-twin

#1

mechanizm

mechanizm

ok, i had the carb-float stick closed on me so i got that fixed. i fired it up and it ran good until i idled it down and back up. the funky mechanism that controls the rpm is not allowing the butterfly to open properly and it starts running super-rich and chugging badly. i can open the carb butterfly by hand and it tachs up well but i just can't control it from the cable. i had this problem long ago and fixed it but now my brain isn't working. if i remember correctly the throttle linkage needed lubrication because it was sticking. i may slather it with D40 tomorrow. is there an easy way to circumvent that maddening and complex idle-up / down and just hook the cable directly to the carb butterfly?


THANKS!


#2

Boobala

Boobala

ok, i had the carb-float stick closed on me so i got that fixed. i fired it up and it ran good until i idled it down and back up. the funky mechanism that controls the rpm is not allowing the butterfly to open properly and it starts running super-rich and chugging badly. i can open the carb butterfly by hand and it tachs up well but i just can't control it from the cable. i had this problem long ago and fixed it but now my brain isn't working. if i remember correctly the throttle linkage needed lubrication because it was sticking. i may slather it with D40 tomorrow. is there an easy way to circumvent that maddening and complex idle-up / down and just hook the cable directly to the carb butterfly?

THANKS!

YOU failed to list your engine model numbers, not sure if this is the CORRECT manual but you can check it out and see the chapters on linkages

https://docs.google.com/file/d/0B6NaqjIxWV1ySkZjTTA5TGltZEE/edit

GET INFO.JPG ......NEXT TIME ...!!


#3

mechanizm

mechanizm

ok, thanks, i'll check it out and will look for an engine # tomorrow. i had this prob before but i can't remember how i fixed it. i THINK that i just lubricated the mechanism. maybe i forgot a spring....


#4

mechanizm

mechanizm

that looks like the engine/carb. when i throttle-up it bogs and barely runs. i can manually hold the throttle rod open and it idles up fine.


#5

BlazNT

BlazNT

WD40 is not a lubricant. Use spray white lithium grease. I put the straw at one end of the cable then tape it very tightly and spray till it comes out the other end. Then move the cable a couple times till it moves freely.


#6

mechanizm

mechanizm

WD40 is not a lubricant. Use spray white lithium grease. I put the straw at one end of the cable then tape it very tightly and spray till it comes out the other end. Then move the cable a couple times till it moves freely.

will do.... thanks! it's raining like a biblical prophecy here in florida so i'll have to wait until it clears. but will buy the white lith today.


#7

mechanizm

mechanizm

just to be clear: it's not the throttle cable that's the problem. it's the spring mechanism below that that's causing problems and i don't understand how it works.

is there a process to remove all of that spring-loaded nonsense and just run the throttle cable to the carb butterfly?


#8

B

bertsmobile1

The thing you are having trouble with is the governor.
The governor slows the engine down by closing the throttle ( which from here on in I will call the butterfly to avoid confusion )
How much it closes the butterfly is determined by how fast the engine is spinning.
The faster the engine spins, the harder it closes down the butterfly,
Working against it is the lever you move which I will call the throttle.
The governor and the throttle are connected together by a spring, called the governor spring and the strength of this spring determines how fast the engine spins.
Inside the engine are some bob weights which rotate a shaft as centrifugal force causes them to be flung out.
The shaft , called a governor shaft pokes out of the engine .
the governor arm is clamped onto this shaft.
SO the shaft moves which moves the lever with moves the wire rod which moves the butterfly.
Google Taryl fixes all - governor .
That should bring up afew videos which will explain exactly how it works and how you adjust it.
If it is broken then you risk major engine damage by continuing to use the engine.


The governor will alter the engine speed about 20 times a minute to keep the engine spinning at the most powerful speed and you have no chance of doing the same by hand


#9

mechanizm

mechanizm

that's what i needed to know. googling now. THANKS!

BUT, i think that you can eliminate that governor assembly and just use common sense when idling-up and get a tachometer to keep from over-revving. these governors are problematic


#10

mechanizm

mechanizm

ok, i've looked at the governor mechanism and everything is moving freely. i can start it up, idle it up but when i change throttle the governor acts up. i can move the butterfly valve in the carb by hand and then the governor starts working properly but i can't change the engine speed or it will go back to chugging. all i did was fix a stuck float bowl and now this...


#11

mechanizm

mechanizm

ok, i believe i solved the problem. after watching the videos on this carb i noticed that THE JETS ARE MISSING. wow.... i've never seen carbs where the jets were held in by o-rings. i assumed that the jets were fixed further up into the orifice. then i watched the video. so i ordered two main jets even though i think that one jet is bigger than the other. i installed them and i'll put the carb back on the john deere L120 this eve. what i think happened is that the o-rings holding those jets in-place shrunk and the jets fell out. what's really weird is that i couldn't find them anywhere. it's possible that they fell out the last time i "fixed" this carb and the float was sticking creating a lean condition allowing the engine to run well. isn't that a coincidence? i can't wait to fire the pos UP and see how it runs. my lawn is getting long in the tooth...


#12

B

bertsmobile1

You are not alone.
The Nikki fitted to a lot of inteks has a similar system and they regularly come in sans main jet, Particularly from clots who think you blow out carbs with the compressor set to 120 PSI


#13

mechanizm

mechanizm

those guys are old-school tinkerers who are used to metal carbs. lol... but i think that this is a flawed design. the jets are all destine to fall out one day. regardless, i'm glad i figured this out. the tractor starts right up now and runs great.


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