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MF12 Rough Idle

1740 Views 11 Replies 7 Participants Last post by  fordmustang1984
Attached is a video of the engine, and a power surge/rough idle. Under load it is fine, but otherwise no go. Also here is a picture of my budget restore as of today..

Notice the custom fishing boat seat, and no battery- I :bannana: love the pull string!

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Does this mean that you figured out what is wrong with your tiller?
Ha, No. I just detached it, and am going to tear it down again this weekend. I think it's the key but when I pull it apart again, I'm going to remove that collar.
Your carb is governor hunting !

Meaning it's starving for fuel!

Throttle shaft ,loose in carb(to much side to side play ) lets air in !

Improper float adjustment .(sticky float)

Restricted low idle passage!

Crap in carb,dirt water etc....

Back out the low idle screw 1/2 turn and see what happens.

When in high rpm mode the low idle passage is still in use ....your engine may sound fine,but it may be running lean ,and lack power,and may the muffler glow cherry red ....unfortunatley the low idle passges are hard to clean,and keep clean ....and are not reapirable a new carb would have to be in order.My 2 cents Jim
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your first part of the response was what I figured. I've tore the carburetor down and cleaned everything that could be cleaned. The problem I see is the throttle arm is lose in the carb body 'egg shaped'. Anyone think Silicone or some type of epoxy and re-drill the hole would suffice?.
Nope,but the throttle arm is brass,and can be replaced...the body can't ....a series of small washers and felt soaked in oil might slow down air getting in though....Good Luck,Jim
if the low idle passages are dirty or plugged ive had some success cleaning them with a set of torch tip cleaners they are about $5-$10 at most places that sell even a small asortment of welding supplies but the small ones even though pretty flexable do break easy so be carefull that you dont break it off inside one of them or use the wrong size and enlarge the passage. use a size smaller than the passage and if you hit a blockage just work it in and out and spray with carb cleaner to soften it
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A reliable machine shop can drill out the body and put in a new bushing for the throttle shaft,or use heavy grease and spread around the base just to keep it from sucking air,last a little bit but is just a temp fix.
Oh man,

Anyone know what the Drive belt and Mower belt should be for this machine?

It's all the way in the back of my property; After cutting for about an hour the 15 year old drive belt let lose, taking out the mower belt along with it :banghead3
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I'm just looking for the length, the width I have... or what was on it anyway.
The carb on my ole MF10 was worn out at the throttle shaft too. I found some plastic bushings out of an old carb kit (for a vehicle), drilled the carb body useing a drill press and put the bushings in. It worked like a charm for a lot of hrs run time.
I have both belts off my MF10. Which one of them broke, I will measure it when I know if it is the front one or the back.
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