My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable

deerel120

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
My decades old L120 (always reliable until this year) has had a fit getting back to normal this year. Replaced starter, fuel lines, fuel pump, clutch, plugs, air filter, one of the spindles and all -- but had removed carb and cleaned it out and in replacing that carb think I've incorrectly attached the throttle cable to the governor adjuster or whatever the bracket down below the carburetor is called. And, to mention this quirk, before I got the mower someone replaced whatever engine it originally had with a Briggs & Stratton Model 350777-1034-A1 (Code 97061711) which bears labels indicating the engine is a 19.5 I/C Platinum Craftsman engine (which is why I believe the engine was replaced -- otherwise why would my Deere have a Craftsman labeled engine, right?).

So, by the way, I believe the carburetor on that engine is an 847395 B&S unit. Whatever. It was running rich. I thought I'd watch Youtube videos and saw Tarryl's video about the little nozzle gasket with four holes at top being clogged up -- but my carburetor is a single barrel and the 841649 part I got was a wasted $6.00 purchase. Fine. However, in investigating the matter (and considering why the engine would run rich) I noted that the choke plate wasn't fully opened up when choke lever pulled back -- so I adjusted that and the engine ran brilliantly -- but at full throttle only and adjusting the throttle lever does nothing about that. Which almost brings me to my question -- after investigating governor adjustments and looking at the whatever that bracket is with springs and stuff with the round plate on front (below the carburetor) I realized that I had probably connected the throttle cable to the wrong hole on that round plate because when I adjusted the throttle lever to low speed it was shoving that plate into wide open throttle. There was a different (lower) hole on that plate so I re-located the throttle cable to that hole and thought that would fix it. Nope. Still running at wide open throttle -- it'll mow and all -- but only without the air filter -- a brand new clean one.

So, my question: Is anyone familiar with the engine model noted above and its governor/throttle linkages? If so, if you could give a bit of advice on how to regain throttle control over the speed of the engine, I would be most appreciative. It could be a missing spring allowing the governor to be wide open. I'm going to see if the governor needs adjustment and get into the operating works of that throttle/governor bracket and see if I can figure out what needs fixing but thought I'd ask for insight and advice if anyone can provide same.

Thanks for your assistance. I'm not really much of a small engine guy -- but will add that I've checked valve clearances and the guides haven't dislocated so that isn't a factor involved (just to note).
 

Catherine

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
:welcome:

Welcome to the forum! I'm going to move your thread over to our John Deere section to see if anyone over there is familiar with it.
 

bertsmobile1

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
You will find step by step instructions for cleaning various carbs here http://outdoorpowerinfo.com/
You lost me totally with your descriptions so a couple of photos would be really beneficial , by preference without the air filter housing so we can see the linkages.
And if possible ut the camera on some thing so the photos are full frame and in clear sharp focus.
 

deerel120

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
Thanks. I'll take some photos as I take a look at it this afternoon.
 

deerel120

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
Was raining last weekend and I didn't get to take pictures -- but here they are. Four pictures: One of the engine configuration with air filter on (0415). Picture 0416 with front air breather removed (and I probably should have taken one of the one barrel carburetor but didn't. Pictures 0417 and 0418 with full throttle and low throttle captions. Still running at full throttle. I took the throttle cable off and rotated the plate manually and still no difference -- engine runs at full throttle and cannot be adjusted or will not adjust. Just runs wide open. Help! And thanks.
 

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bertsmobile1

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
OK,
Firstly are you sure that the cable comes in from the right side ?
The photo looks like there is a wear mark on the left side cable clamp.
Next the engine is controlled by the governor, the throttle cable sets the upper limit that the governor can open the throttle to.
The lever in the background to the left is the governor and that lever should be connected to the throttle control by a spring so that the spring is pulling the carb butterfly closed
 

deerel120

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
Yes, throttle cable comes in from the right side and the spring to throttle butterfly is attached, it is (however) pulling the throttle butterfly fully open at all times. But, like I said, even with the throttle cable removed rotation of the plate makes no difference -- throttle butterfly is in wide open position. I'll take pictures of the carb itself and send later. Thanks for your reply.

OK,
Firstly are you sure that the cable comes in from the right side ?
The photo looks like there is a wear mark on the left side cable clamp.
Next the engine is controlled by the governor, the throttle cable sets the upper limit that the governor can open the throttle to.
The lever in the background to the left is the governor and that lever should be connected to the throttle control by a spring so that the spring is pulling the carb butterfly closed
 

bertsmobile1

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
The throttle should always be open fully when the engine is turned off regardless of what position the throttle lever is in because the governor spring is stronger than the throttle spring.
When you move the throttle control, the wire turns that plate.
The plate stretches a spring between it and the GOVERNOR ARM the governor arm should be the only thing connected to the throttle butterfly and that has to be a solid rod.
The spring pulls the governor shaft into the open position.
The engine rotating mover the governor into the closed position.
When the engine is stationary the governor holds the throttle wide open
As soon as the engine starts to turn the governor closes the throttle down to whatever position you have set the throttle control to.

Put your finger on the governor lever, you should be able to move it by hand to fully close the throttle butterfly.

And remember the throttle butterfly is the one that you can not see at the back of the carb nearest the engine.
The butterfly at the front is the choke.

People not familiar with these engines get them confused and on some engines you can transpose the control cables
 

Travlitt

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
Was raining last weekend and I didn't get to take pictures -- but here they are. Four pictures: One of the engine configuration with air filter on (0415). Picture 0416 with front air breather removed (and I probably should have taken one of the one barrel carburetor but didn't. Pictures 0417 and 0418 with full throttle and low throttle captions. Still running at full throttle. I took the throttle cable off and rotated the plate manually and still no difference -- engine runs at full throttle and cannot be adjusted or will not adjust. Just runs wide open. Help! And thanks.

The trottle cable should be conected in the bottom hole on the throttle disk, not in the top hole.

http://outdoorpowerinfo.com/repairs/briggs_intek_v-twin_carb.asp
 

deerel120

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  • / My Deere L120 runs full throttle -- think I've incorrectly attached throttle cable
The throttle should always be open fully when the engine is turned off regardless of what position the throttle lever is in because the governor spring is stronger than the throttle spring.
When you move the throttle control, the wire turns that plate.
The plate stretches a spring between it and the GOVERNOR ARM the governor arm should be the only thing connected to the throttle butterfly and that has to be a solid rod.
The spring pulls the governor shaft into the open position.
The engine rotating mover the governor into the closed position.
When the engine is stationary the governor holds the throttle wide open
As soon as the engine starts to turn the governor closes the throttle down to whatever position you have set the throttle control to.

Put your finger on the governor lever, you should be able to move it by hand to fully close the throttle butterfly.

And remember the throttle butterfly is the one that you can not see at the back of the carb nearest the engine.
The butterfly at the front is the choke.

People not familiar with these engines get them confused and on some engines you can transpose the control cables

Great information -- I've never been schooled on the functional mechanics of how the governor operates. Really appreciate the insight. Will advise what I'm able to do with it. Thanks.
 
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