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Setting RPM


JFS321's Avatar
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07-13-07, 07:50 PM   #1  
Setting RPM

Before I had the gas/oil mishap, a repair guy set the RPMs on my mower. The governor linkage still moves, but doesn't change the engine speed at all. Can anyone tell me how/why this happens in case I want to get the throttle working again? He never took the flywheel off or went inside the engine. Thanks.

 
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cheese's Avatar
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07-13-07, 08:17 PM   #2  
If the governor arm movesm but the rpm doesn't change, you have a mechanical problem. You'll have to visually inspect to see the problem. The repair guy may have rigged it.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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07-13-07, 08:21 PM   #3  
Well, that's why I'm wondering what he did. Maybe he DID remove the flywheel, but he never mentioned going anywhere that deep, and didn't charge me much. I don't understand what makes the governor keep the constant speed now, even with the lever moving. The engine isn't running wide open.

 
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07-13-07, 08:28 PM   #4  
There's nothing under the flywheel that affects governor operation, or rpm. The governor is normally driven by a gear inside the engine. Movement of the governor arm is supposed to move the linkage to the carb throttle, causing a change in rpm. If it is not changing, you'll have to look at the connections between the governor and carb and see where the transfer of movement is lost.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-13-07, 09:09 PM   #5  
some engines have a plastic paddle that moves with the air from the flywheel. If it spins to fast the air pushes the paddle which moves the linkage on the carb causeing it to slow down. its possible this could be missing or not hooked up.

 
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07-14-07, 02:32 AM   #6  
What is the engine and what are the ID numbers? Does the mower have a throttle control? Why did the repair guy do what he did?

 
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07-14-07, 04:19 AM   #7  
Wondering if maybe the air vane has been rigged or is in a bind. Might take the shroud off and check that the vane moves freely. Are you moving the gov arm manually and getting no change in rev's? If so, strange that the rev's do not change. Maybe the vane is broken. I'm trying to remember if the vane just sits on a stud or has a screw hold down. If it is a screw and no movement, check the screw for being to tight/wrong type. If the vane moves and has the RIGHT undistorted gov spring, it should function as it did before.

I'm assuming this is a mower with the wind vane at the flywheel, and I'm picturing a screw with a smooth shaft with a few threads on the end that holds the vane in place and allows it to move. If this is the vane type and you do move the arm attached to the vane where the gov spring attaches, the rev's should change regardless if there is a broken vane or not if the gov spring is right as this should move the throttle. Then again, different mowers have different setups and I may be totally wrong.

 
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07-14-07, 09:19 AM   #8  
Thanks for all the replies...I'll post more info a little later when I try some of the tips.

The engine is a B & S 120602-1038, OHV and 6.0 HP. The throttle lever on the handle moves up and down, and this does move the governor level back and forth.

 
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07-14-07, 09:30 AM   #9  
And I don't think this mower has the air paddle...at least I didn't see on EMPARTweb.

 
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07-14-07, 12:49 PM   #10  
I remembered this engine from previous posts...it does not have the paddle/vane type governor.

The only common engines with vane governors are the briggs classic engines.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-25-07, 08:28 AM   #11  
Okay, so I've been trying to fix this thing. It seems that no matter where the arm moves, the engine still surges. And its a real pain to work on...I have to put in and take out two bolts and the gas tank every time I want to adjust the governor arm.

With the governor arm "stretched", away from the engine...should that speed up or slow down the mower? And if I set the arm in a certain place, would the RPMs then stay constant? Thanks.

 
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07-25-07, 05:13 PM   #12  
Did the engine surge orginally? Sounds like you have more than one problem now. An improperly set govenor will cause a surge plus dirt in the carb. The throttle on the handle bar moves a lever on the carb which connects to a spring on the throttle rod.

 
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07-25-07, 06:51 PM   #13  
On some mowers with briggs engines the throttle linkage on the engine has several option it can be use with throttle linkage, without linkage, or a set speed there is a wing that is part of the linkage that can be bent down to come in contact with the linkage housing stopping excess travel, so when the motor is started it has one speed. Check the next time you are looking at a low end, no throttle, briggs powered mower. Maybe the tech. set the wing for one speed. The surging is a different issue, you need to remove and clean the carb it is starving for fuel. And quit bending things, you will never get it right, I have yet to read a service manual that suggested bending anything. Put it back the way it was, clean it and all will be well(hopefully). Have a good one. Geo

 
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07-26-07, 04:17 AM   #14  
Perhaps you are off on the governor adjustment and also need a new governor spring and the Briggs service manual, part number 272147, along with a new spring, Briggs part number 691290, may help you greatly. Check with your local Briggs shop for these.

 
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