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Discussion Starter #1
Toro Wheelhorse with a B&S 283707 type 0156-01 9303044D

This has gotten to be the machine from ****, with one thing after another breaking down. The best I can describe this is a failure of the governor after running about an hour. I mow at about 3/4 throttle, never wide open. After mowing an hour the engine will race to WOT and the throttle control is ineffective. I've been trying to understand how the governor works, and if I'm right, it prevents the engine from over-revving and blowing up.

The carb has been rebuilt, cleaned and blown out, the linkage springs are free, but it has a mind of it's own. I have a tow-behind sprayer that I need to use but the engine on the tractor won't allow me to slow down to a good spraying speed even in 2nd gear.

Anybody have any idea what's causing this? I've posted something about this before and I've been through static governor adjustments, gas flooding the carb, nothing seems to help. From the looks of some of the threads, I'm not the only one with this problem.
 

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:howdy: Put on your thinking cap and read on:

Understanding and Adjusting Your Governor

Generally Governors should never need to be adjusted, unless the governor arm has been removed or tampered with. In the event that they do need adjusted, here is how to do it.

One of the most important parts of your engine is the engine governor. An improperly adjusted governor can shorten your engine's life. If engine speed is not controlled, the engine will destroy itself. Never run an engine over speed, especially without a load attached to it. Even for a short period of time it can cause catastrophic failures, like blowing the magneto magnet into 100's of little pieces. Over speeding is something that needs to be taken care of immediately, because it can be a real hazard with metal coming loose at high speed. This page will explain how to adjust the mechanical governor on Briggs and Stratton and Tecumseh Engines.

First, let's understand a little more about governors and why they may not be working right:

Most complaints about governors fall into two categories:
Engine runs too fast or too slow.
Engine surges or hunts.
You should do an inspection of the governor linkage and spring before trying to solve either of these problems. Make sure everything is operating freely and the spring is not damaged or stretched. Also, check the governor static adjustment to see that all free play has been removed between the spindle and carburetor. The best way to do this is to move the throttle from idle to full open and note the way the governor shaft moves. If it goes clockwise, then loosen the clamp screw and with the throttle wide open turn the shaft all the way clockwise and re-tighten the nut. Make sure the throttle moves from idle to full open freely after making the adjustment. Refer to the engine repair manual for exact adjustment procedures.

After you have made the above check, restart the engine and see if the governor now operates correctly. With the engine at idle, move the governor lever with your finger to open the throttle and it should push the arm back toward idle if working properly. One way to do this test is with the governor spring removed. If it still over speeds or has no push toward idle, you probably will need to have the internal parts checked inside the motor or recheck the static adjustment. See your local repair shop for this!

The other problem that often occurs is governor hunting or surging up and down. Most of the time this is not the problem of the governor, but a partially plugged carburetor, usually a plugged idle circuit or worn linkage. If you can rule out these causes and have checked the adjustments I talked about above, then you may have a governor that is set too sensitive. In other words it reacts too quickly and over compensates for the speed. Many governor arms have several holes in the arm to change sensitivity. By moving the governor spring to a hole further away from the governor shaft you will make it less sensitive. Before playing with this, check the repair manual for the engine you have and see if it has a way of adjusting sensitivity. Sometimes you may have to change governor springs, etc.

Many of the smaller lawnmowers used what is called an "air vane governor". This type of system uses the air flowing through the engine to operate a vane back and forth against a spring, just like the mechanical governor does. The big problem with air vane governors is debris sometimes collects in the system blocking air flow. When this happens the engine will over speed. So, with an air vane system it is very important to keep the cooling fins clean so the proper amount of air can move through the engine. The governor spring is precisely calibrated for an engine that has full air flow going through it. If the air flow is blocked it can over speed the engine.


SOOOO--->

To adjust the governor on a Briggs and Stratton horizontal shaft engine, you would loosen the nut on the governor arm and push the governor arm down, clockwise. Then you would turn the governor shaft clockwise also and tighten the nut
 

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Discussion Starter #4
I read the same article online before I posted so none of the mechanical stupidity would leak out and show!! Keep in mind that when first started, everything works the way it's supposed to. ( governor arm tries to return to idle if I put some pressure by hand on it to rev up.) Once the engine is hot after mowing an hour, the governor arm maintains some pressure to keep it at high speed.

Migraineman- I just rebuilt the carb and made sure no parts were missing or loose.
 

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Are you sure you put things back together just as they were 'pre-rebuild'?

Its weird how it only over-revs when hot though.. You are the first one I've seen with this trouble for sure.. Usually if a Governor doesn't work, (he moves to NY) it doesn't at all..

Check your throttle plate innards as migraneman suggests..

Perhaps a picture of your carb to governor linkage and throttle linkage could help us to steer ya right.. Just a thought..

Is the Governor arm loose on the governor shaft? I'd readjust the Governor's Static setting and go from there..

Do you have a hard rod or link between the arm and the throttle lever?

Just a few thoughts..
 

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Discussion Starter #6
I hope this photo comes thru---
ok. The governor arm is on the right, in the photo the engine is off. When hot and over-revving, the arm is pinned to the left and needs finger pressure from left to right to get it to idle down, but immediately springs back to the left.
I'll really have to search my memory to see how this comes apart so I can check static governor adjustment.

 

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no need to disassemble it..

Look under where the throttle cable is mounted, you will see the bottom of the governor arm, and the nut. Its 3/8"...back it off a turn or 2...and hold the throttle (engine off), wide open, while turning the governor shaft that sticks out the block, clockwise, until it stops. Without moving anything, tighten the nut back up, good and tight.
 

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Discussion Starter #8 (Edited)
I'm an idiot.
I just found out this problem has nothing to do with the governor. Here's a pic of the inside of the air cleaner housing after running a while. See the lake of gas down there on the right side?
I left the housing off so I'd have a better view of the governor for adjustment. For the heck of it I hit the starter and it started right up.....with gas pulsing out of the carb throat. The mixture screw is useless, doesn't have any effect. The governor also works opposite as I described above. It's pinned to the left, but the left is carb closed, not wide open.

I put in a new needle and cleaned the seat just as RED said a week or so ago, but after reading this thread http://www.mytractorforum.com/showthread.php?t=314817 maybe I didn't clean it good enough. I'd work on it some more but this is Michigan and it's only 45 degrees out there. The new needle is the right part number and the same size. The float doesn't have gas in it.

 

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make sure you dont have gas in your oil at this point. Unhook the rubber breather hose from the housing and see if, while running, gas/oil sprays out while running.

Gas coming from the carb throat, is odd..usually means a valve problem, from compression leaking past the intake valve and blowing the gas back, or a timing problem..such as from a sheared timing key...or, a flooding problem from a sticking needle/seat/float.

If it doesnt flood while sitting...then its not likely the carburetor....
 

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I thought I had it a couple weeks ago when I found that the fuel line was disintegrating on the inside and spewing chunks into the carburetor. Since that's the easiest thing to get apart, I'll check that again. first thing. RED, I thought of a valve problem, too. But I didn't want to take myself seriously unless I heard it from you. And, intake valves usually stay clean, don't they? It's carbon buildup on exhaust valves that stick those open. I guess I need to ask for a good engine diagram so I can see how it all goes together...and comes apart.
One other thing, before I installed a new needle and over the winter, the gas tank drained into the crankcase. Crap in the carb would let that happen again.
 

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ok. The carburetor bowl had black chunks again. The bowl gasket is breaking down. I'll get one tomorrow.

Then I pulled the plug lead and put a small rag near the opening of the the intake manifold and hit the starter. It pulsed pretty strongly. Sticky valve. Gotta find an engine diagram.
 

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While cranking, the compression release will make a "pulse" out the intake....

Black chunks in the bowl is bad, do you have a fuel filter in the fuel line up near the carburetor?
 

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Discussion Starter #13
Yes, and for the heck of it I put in a new filter and bowl gasket. The black chunks in the bowl were rubber, and I noticed the inside edge of the bowl gasket was coming apart, so new gasket.

Didn't help at all. If the governor gear wasn't working, the arm wouldn't be pinned to the low speed side. I really don't want to do heart surgery just to see if it's ok. Another guy I know had the same problem, and it wound up being a sticking float/needle/seat.

I've had that carburetor apart 20 times. I didn't lose a spring or other small part. The carb diagram shows a simple float/needle/seat. But something isn't allowing it to close. There's no adjusting tang on the float. I hate buying "let's try this" parts.
 

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does this thing have a plastic, or metal intake manifold?
 

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Discussion Starter #15
The intake manifold is aluminum. This morning I noticed a lot of play in the butterfly shaft. Air leak? With the governor arm at the low-speed side, which means the butterfly is closed, where is it getting enough air to run WOT all the time?
 

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Dunno...more troubling is, its getting AIR and GAS to run fast...because even if it had an air leak, it would just lean out and surge up and down...its over revving, meaning its getting too much air, and fuel...in the proper ratio.
 

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Discussion Starter #17
The throttle shaft was really worn down to an oval shape at the lower end where it bottoms into the carb. Nothing open, so I used jbweld on the shaft and tomorrow I'll file it into shape. Brass vs. aluminum and the aluminum won.

Unless the governor has popped apart, I'll know if a new carburetor is in my future tomorrow. I'm getting tired of taking it apart.
 

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Discussion Starter #18
Well, I think that was it. Shaped the jbweld and put it all back together. And it ran like it was supposed to. The governor was working fine. I had throttle control for an hour and a half before the repair wore itself back down. I guess it doesn't take much of an air leak at the butterfly to lose throttle control. RED, it had enough of a leak to really suck in the fuel.
So tomorrow I'll get a new shaft and put it all back together for (maybe) the last time.
 

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Discussion Starter #19
That was it. Worn out throttle shaft. A half hour and $15.00 later it runs like new. Except that weird noise out of my mower deck. 2/3 finished and the deck belt broke. Keep me away from your machines. I must be a Jonah.
 

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Had a 2 machines in a row like that a couple months ago. Wouldn't hold throttle settings. On one, the throttle shaft was wiped out where it keys into the throttle lever on the top of the carb......so the throttle plate was just wandering around to any opening it wanted. On the other the shaft was wiped out like yours. I don't put parts in these carbs, I just replace the entire carb. Otherwise, it becomes a huge waste of my time.

Glad you got it fixed! Good job hanging in there.

BTW, you're not the problem with that machine, it's just got a lot of hours on it, and it's not been well cared for. I'm sure if you pop that deck off, you'll find tensioner pulleys that rumble, and probably spindles too. If you bite the bullet and replace everything at once, you can go back to mowing and never worry about it again.
 
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