# Lawn boy F Series Help?



## Okie294life (May 1, 2020)

I have a lawn boy f series commercial mower won’t run right. I’ve adjusted the idle screw to 2 turns, loosened the governor vane out about as much as possible and I’ve cleaned the carb. At low speed it runs fast, at high speed it runs slower and dies, but it idles down, really weird. This has to be something simple?


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## mexicanyella (Jun 12, 2020)

I would suspect an air leak, possibly through worn crankshaft seals. Can you look for evidence of oily blow-by under the flywheel or down under the deck where the crankshaft comes out through the “muffler donut?”

This happened to me on a F-series I picked up cheap off of Craigslist a few years back. I’d always wanted a Lawn-Boy. 

I ended up scrapping mine, because the deck design wasn’t ideal for the mowing I do. It worked great for a fine cut on short grass, but what I need is a mower that can cut taller, thick grass and get rid of clippings in a hurry. Without getting clogged up with juicy clover pulp. The Lawn-Boy was light and ran smoothly, for awhile, but the low, flat deck and small outlet chute clogged easily and when the motor got too tired, suddenly the trash-picked Poulan Pro Briggs-powered high-wheel mower I found seemed like a better solution. That thing is noisy and vibrates more, but it can blow through some tall grass and scatter those clippings.

I used to work summers at a golf course, which had a fleet of about 10 commercial Lawn-Boys. The greasable metal wheels and cast decks and big gas tanks were great and being two-strokes, they worked well on steep bunker faces. We had a lot of problems with the rear-wheel friction drive system and it’s nylon bushings and friction rollers. But even disengaged and free-wheeling, they were pretty nice, stout mowers in that environment of short bluegrass and fescue...neither of which tends toward clogging things up with pulpy green goop.

They even survived being run on 100:1 Opti-2 premix, which always seemed like a risky proposition to me. A few got straight-gassed over the years by the weed-burning newbies on the mowing crew, and I remember the mechanic saying Lawn-Boy F-series short blocks were getting hard to find (this was in the early-to-mid ‘90s).


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## Okie294life (Jun 12, 2020)

Thanks for the advice. A lot of the poor idling seems to have been around the throttle cable that was broke, but it will still run for a while and randomly choke out. I’ll pull the mag and muffler to see if it needs seals.


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