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tecumseh overspeeding...help!


gmcfan's Avatar
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04-13-04, 10:30 PM   #1  
gmcfan
tecumseh overspeeding...help!

hey all! I have a Yardman with a Tecumseh engine Model LEV120, single speed. I had to replace the magneto, even though we have only used the mower for about a year! (I will take a B&S any day) But I had also removed the carburator, because I was having fuel delivery problems. Well, now I can't remember where the governor linkage hooks up to the throttle! Now when I start it, it over revs, and I shut it down immediately.

If I am correct, the throttle stays wide open while the engine is off right? and when the mower is running, the governor pulls it closed, and when the mower boggs down, the governor opens the throttle more, right? I have tried it in all of the various holes that are on the top of the throttle, but to no avail. Could I have bent the linkage when I was messing with it? Does anyone know which hole the linkage is supposed to be in? I need this thing to mow our yard, getting kinda tall.

Thanks all!

 
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jughead's Avatar
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04-14-04, 12:36 AM   #2  
I would suspect that the arm on the governor shaft has slipped.

You are correct, when the engine is off, the throttle should be in the full open position, and when the engine starts to overspeed the governor should start cutting the throttle back. When the mower operator moves the throttle from the operator's position all he is really doing is adjusting the tension on the governor spring. In other words, the spring tends to hold the throttle open and the governor tends to force the throttle closed.

I don't exactly know what you could of done wrong by removing the carb, but, if you disturbed the position of the governor arm on the governor shaft you could easily get the engine overspeed condition that you described.

What you can try is this: Move the throttle on the mower's handle to a low speed position. Now feel how much force is needed to move the carb throttle linkage towards a slower speed position. Only a very small force should be necessary. If a large force is necessary the governor arm may have slipped on the governor shaft and will need to be adjusted.

To adjust, loosen the screw that holds the governor arm to the governor shaft and move the relative position of the arm on the shaft and retighten. Check the force necessary to move the carb throttle linkage again and see if you need to make it tighter or looser. You can also move it enough so that the spring will tend to actually move the carb throttle linkage towards engine shut off. If that's the case you went too far. You want it so the linkage moves the carb towards full throttle, but only a little force is needed to move it towards a slower speed.

The smaller the necessary force needed to move the carb throttle linkage toward a slower speed the less force (and a slower speed) will be needed by the governor to cut the throttle.

If you make it so a very small force is needed the worst that will happen is that you might not get your engine turning up to a speed necessary to cut your grass. After you try a few different settings you will gain sufficient experience so you can tell about how much force you should feel on the throttle linkage to get the engine turning about 3200 rpm when at full throttle and about 1800 at minimum throttle. The different holes in the arm are more for adjusting how the engine will react to a load change than for adjusting the absolute speed. If you get the engine adjusted so that it's running at the proper speed and it bogs down way more that usual in heavy grass, then you can move the linkage to a hole further out on the governor arm to give the engine a lilttle more throttle. I suspect that you will be fine if the linkage is in one of the middle holes.

Perhaps your governor is also stuck inside. That could also explain why it's overspeeding. In that case you will have to take the engine apart to fix it.

Hope this long winded explaination is sufficient. Governors can be a little tricky to adjust if you really don't understand how they work.

 
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04-14-04, 11:13 AM   #3  
Whoa!

Before you mess with adjusting your governor static load setting, let us know if you have an authorized Tecumseh service center in your area first. Why? Because you likely didn't foul this up by merely removing the carburetor. It is much more likely you just don't have the linkages in the correct holes. For us to try to tell you which holes to use would be almost impossible since there are many options, which is why I ask if you have a Tecumseh center in your area. If not, let us know and i'll try to attach a crude drawing with the next post if necessary.

 
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04-14-04, 11:21 AM   #4  
You could also get a service manual for your model from your tecumseh dealer. It would be good to have one anyway so you can do maintanance on your engine and replace parts.

 
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04-14-04, 11:06 PM   #5  
gmcfan
I got it running right. After some trial and error, it runs about where it was before. I will try it out tomorrow, and make adjustments if necessary. Thanks for the help guys!

 
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