Older Lawn Boy Push Mower Idles Really Slow

[gmaruna]

I recently purchased an older lawn boy push mower (model is 8241AE). I got it for real cheap, the guy I bought it from didn't know if it ran or not.

It is electric start only, and with fresh gas and a new battery it started right up. But the problem is is that the engine speed and therefore the blade speed is really slow. It's almost as if it's on choke mode, but from what I can tell on the mower there is no choke or throttle levers at all. I watched a YouTube video where the guy said the governor control was underneath the flywheel, so I took that apart but it was not there, the only control that I have seen is there's a small plastic knob that comes up off the carburetor but it doesn't seem to affect much if I adjust it.

I know these are kind of collector mowers and I really want it to work right and I think it will, but I am really at a loss in terms of what to do to get it to run right. I work on motors regularly, but this one has got me stumped.

I wanted to reach out and see if there is anybody that works on these older lawn boys that could give me some direction. I appreciate any and all help!

 

[stretch5881]

There is a very good chance that you have to take the exhaust apart to clean the carbon out of it. That is a regular maintenance on them.
If that does not help, the knob you turned on top is for low and high speed. It connects to the air vane governor system and could be that something is missing or disconnected.

(PDF) 26622228 Lawn Boy Service Manual 1950 88 Complete - DOKUMEN.TIPS

This Service Manual i s Dedicated t o FIRST -- - Lawn-Boy Service Accountseverywhere. - Our Lawn-Boy It has been designed for your use-primarily. SECOND Retailers. If theywilluse…

dokumen.tips

 

[gmaruna]

There is a very good chance that you have to take the exhaust apart to clean the carbon out of it. That is a regular maintenance on them.
If that does not help, the knob you turned on top is for low and high speed. It connects to the air vane governor system and could be that something is missing or disconnected.

(PDF) 26622228 Lawn Boy Service Manual 1950 88 Complete - DOKUMEN.TIPS

This Service Manual i s Dedicated t o FIRST -- - Lawn-Boy Service Accountseverywhere. - Our Lawn-Boy It has been designed for your use-primarily. SECOND Retailers. If theywilluse…

dokumen.tips

Thank you! I will try both of those things

 

[slackinoff]

@stretch5881 - is correct on the carbon in the exhaust port. It's regular maintenance on these and no big deal especially since when taking the blade off to give it a good sharpen, you are most of the way there to the exh ports.

I do my exh ports once a season on the 1994 Lawn Boy 10515. When I first got it, two of the three round ports were completely blocked. They run a hell of a lot better when cleaned out, ha!

Mine also took some fiddling with the mix screw and air gov knob to get the idle speed and max speed correct. Listen for engine ping when she's fully warmed up....if you hear that you need to richen up that mix screw a touch.

 

[ray benson]

There is a very good chance that you have to take the exhaust apart to clean the carbon out of it. That is a regular maintenance on them.
If that does not help, the knob you turned on top is for low and high speed. It connects to the air vane governor system and could be that something is missing or disconnected.

(PDF) 26622228 Lawn Boy Service Manual 1950 88 Complete - DOKUMEN.TIPS

This Service Manual i s Dedicated t o FIRST -- - Lawn-Boy Service Accountseverywhere. - Our Lawn-Boy It has been designed for your use-primarily. SECOND Retailers. If theywilluse…

dokumen.tips

Thank you! I will try both of those things

Here is that file compressed to about 26meg instead of 141 meg.

 

[stretch5881]

Thanks Ray.

 

[LAWN BOY]

Did you ever get this figured out? I’m also in Wisconsin. I was having the same problem with my old Lawn Boy last Summer, my muffler was clean so a couple Lawn Boy experts told me the ignition coil could be going out, so I replaced that, no luck. Finally, I found that my governor spring was bent out of shape and fell out of proper placement.

 

[AnthemBassMan]

Lawn-Boys? People still use those mosquito foggers?? I know, I know. My three mean green machines pale in comparison to a lot of others.


L8R,
Matt

 

[Moparmyway]

Does the one on the left still have points ?

Middle one came with electronic ignition, IIRC, and the one 1/4” fuel mixture adjustment on the top of the carb ??

 

[AnthemBassMan]

Does the one on the left still have points ?

Middle one came with electronic ignition, IIRC, and the one 1/4” fuel mixture adjustment on the top of the carb ??

Mine? Yes, the Bricktop has points/condesor and it still fires up on the first of second pull every time. The one in the middle has the single adjustment screw facing forward on the carb. It’s what they call the altitude adjustment but it still affects the fuel mixture. I can’t remember for sure, but Lawn-Boy started using electronic ignition in 1973, but the Bricktops used points/condensor until they quit making them around 1980-81.

L8R,
Matt

 

[Moparmyway]

I worked on LawnBoys as a HS teenager back in the 80’s …….

Love them !!!

Every below deck muffler got the burp gun in the weephole to open it up to about 1/2”. They ran much better and were only marginally louder. Kept the exhaust ports clear too