# Lawn-boy mower governor control



## DHowell (Oct 15, 2012)

I volunteer for a 17 unit Transitional housing group and keep the mowers running. Used mowers are donated. I have 2 similar 2-cycle lawn-boy. One is a Model #10550. Both of them start okay,but both surge up & down. The top rpm is very high. The govenor arm oscilates back and forth. Is there an adjustment that can be made or do I need new parts?


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF.

Your are going to have adjust the mixture screws on the carb. Probably running a little to lean. You have a lean hunt condition.

If that does not help, clean the carb good or rebuild the carb, assuming you can find a rebuild kit that has new mixture screws.

BG


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## DHowell (Oct 15, 2012)

Thanks. There are no external adjustment screws on these two mowers. A third Lawn-boy has an adjustment screw and I was able to get it running okay. I will try cleaning it again. The nonprofit doesn't want to spend a lot on repair parts when they can get other mowers. We seem to be getting a lot of Lawn-boys.


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## mortimer snerd (Jul 17, 2011)

I got you. First thing is me getting a mental picture of which engine this is. You don't have a digital camera, do you? Meanwhile I'll see what your model number brings up on the Web. I'm checking some stuff now, meanwhile don't listen to what anybody else tells you to do. I've spent 40 years fixing mowing machines other mechanics screwed up!


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## mortimer snerd (Jul 17, 2011)

You might hate this but I want you to "begin at the beginning" and I promise you there will be an end with a perfect result! Engines want, IN ORDER, "compression/airflow.....ignition+good sparkplug - - - and then and only then can you find the carburetion"sweet spot" ". Please do it this way: I want you to check the compression in the combustion chamber AND ALSO check for vacuum leaks INTO THE CRANKCASE. Why? Because 2-cycles first use the reed valve/piston port and underside of the piston to draw in fuel-air mixture through the carburettor. Your carb has no adjustments. Why? Because for a century ******* mechanics have neglected the basics and preferred to twist adjustments. Ready? Disconnect spark plug and turn machine on it's side. When you turn the blade in the right direction, and then when you turn it backward, does it feel like there is a coil spring trapped above the piston?( i.e. very good piston ring seal) ? Second: Take the muffler off and clean it out. CAREFULLY CAREFULLY remove almost all the built up carbon out of the cylinder exhaust ports. DO NOT DAMAGE THE PISTON OR CYLINDER. Then look for "juiciness" around the crankshaft seals, Top and Bottom. And around the parting line where the cases bolt to each other. Is the crankshaftor blade visibly bent? Imbalance WILL eventually destroy the bearings and shake the engine apart. Get back to me.


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## Basementgeek (Feb 7, 2005)

What I gave them is the first thing to try for a lean hunt condition.

BG


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## DHowell (Oct 15, 2012)

Thanks I will do thise items. I am busy, it may be a couple of days.


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## DHowell (Oct 15, 2012)

Conpression seems ok. No leaks aroung shaft bearing. Took cover off the box above the mower blade that the exhaust "U" tube comes through. "U" tube had slight buildup. Cleaned it out. There was no sign of any carbon in opening to piston chamber. Put cover on without any seal. Origional seal looks like a bead of rubber cauking. Does it need to be sealed? Mower wouldnt start. Duu! Forgot to connect sparkplug. Runs with less surge. Runs better as it warms up. RPMs seem to be 2X more that any of our 4 cycle. Is that normal for a lawn-boy? 
Whats next? I haven't cleaned the carb. on this one yet.


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