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Traded a hardly used, basic push mower for this antique. Never had an LB before although I have worked on my friend's. Put in fresh gas (50:1), a little starter spray and hooked it up to my 12V battery charger. It started, but smoked a ton, eventually clearing and then I cut some grass with it. Self propelled feature does indeed work.



Curious there is no pull cord for starting. That handle is begging to be shortened behind the rear wheels (will not do). Catcher bag is long gone.

Ordered a new battery that is slightly larger than the box in one dimension. I think I can make it work with some washers and longer bolts.

Spark plug was loose - and it still ran! Fixed that and replaced one of the handle bolts at the wheel mount. Handle is more upright now after adjusting/tightening. All simple and it's ready for some action. The wheels have grease zerks. Now where is that grease gun?

How well does this work without the bag to catch the grass? If you have the door open, doesn't it shoot the grass right at you? I parted out one of these last fall because I didn't have the bag and, without the bag, the handle is (to me anyway) embarrassing.

FuzzyDriver said:

How well does this work without the bag to catch the grass? If you have the door open, doesn't it shoot the grass right at you? I parted out one of these last fall because I didn't have the bag and, without the bag, the handle is (to me anyway) embarrassing.

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I've mowed some with the door closed which worked fine. Even w a bag I don't understand the handle design because of so many other brands that allow the bag to go back past the handle. It is goofy. I'd cut a section out and re-weld it, but then all the cables would need shortening the same amount. Oh well.

The 8481AE was built between 1986 and 1988.

Why L-B decided to build a 20" Deck Commercial Mower is beyond me.

I've got the same basic mower but non-commercial, it is a 8125 built in 1984. Main difference is on mine the drive is actuated similar to the old capstan drive where a short section of top handle bar is swung forward about 90Deg to drive & pull back to stop.

The actuation on this later model you have is really strange ... I've seen pictures of it before and there are instructions for how to adjust it in the Suburban Service Manual, but never seen one in person.

I did find a new bag and a mulch plug for this 8125 on ebay a few years back.

Cleaned the main jet with a spun wire cleaner and it starts right away now. Surges some at an idle, but runs evenly at the top end.



Adjusted the drive cable so it moves sooner when you push on the handle, cleaned the plug, sharpened the blade. All ready to go except for the battery. Still waiting on that. I like this mower. Does a nice even job.

Models with that type of handle design were known as “school bus” models because they were like trying to maneuver a long school bus in tight places. I suppose the real purpose was to allow easier cutting under thick hedges. They are not a favorite of mine, but hey, it’s a classic 2 stroke Lawn Boy that runs and operates.

Battery came, so I installed it. Before I did I checked the voltage coming back out of the machine while it's running and it's 45 volts. Will have to check Amp hours coming back out as well...

2smoked said:

Models with that type of handle design were known as “school bus” models because they were like trying to maneuver a long school bus in tight places. I suppose the real purpose was to allow easier cutting under thick hedges. They are not a favorite of mine, but hey, it’s a classic 2 stroke Lawn Boy that runs and operates.

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Just might shorten that part of the handle eventually. It is tough to turn in the tight spots. Thanks for your note.

Check "Ah"? Is that a typo?

FuzzyDriver said:

Check "Ah"? Is that a typo?

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Meant to say Amp hours or Amps, whatever. I'm no expert on electricity. I've decided to assume the output from the mower is correct. I've matched the battery closely except for size so will go with it. Saw documentation somewhere that there is output from mower back to battery which I believe is not the case with the Toro electric start I'm also fixing. This LB is working fine so far. I've mowed once and stored it in my shed and it starts up every time I've tested it.

OK, thanks. I'll try to help with the terminology.

An amp-hour is, as the name implies, an ampere of current flow for an hour. This is a battery rating, since batteries are storage devices, as opposed to a generator, which produces potential power as long as it's being turned (not a storage device). A battery can have a rating like, for instance, 20 Ah which means it would be dead after the amount of current you draw from it times the hours you draw that current equals 20. 20 Amps for 1 hour, 10 Amps for 2 hours, 4 Amps for 5 hours - any combination that multiplies out to 20. As you can see, Amp-hours for a generator doesn't make sense - it can put out 20 Amps (or 10 Amps or 4 Amps) forever as long as you keep turning it.

If I can help with anything else, electricity-wise, let me know. Have a good day!

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FuzzyDriver said:

OK, thanks. I'll try to help with the terminology.

An amp-hour is, as the name implies, an ampere of current flow for an hour. This is a battery rating, since batteries are storage devices, as opposed to a generator, which produces potential power as long as it's being turned (not a storage device). A battery can have a rating like, for instance, 20 Ah which means it would be dead after the amount of current you draw from it times the hours you draw that current equals 20. 20 Amps for 1 hour, 10 Amps for 2 hours, 4 Amps for 5 hours - any combination that multiplies out to 20. As you can see, Amp-hours for a generator doesn't make sense - it can put out 20 Amps (or 10 Amps or 4 Amps) forever as long as you keep turning it.

If I can help with anything else, electricity-wise, let me know. Have a good day!

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The volts coming from the generator in this mower is 45 although the battery is 12. Is that a problem? If so, perhaps I need a new generator and perhaps it toasted the original battery.

How do I check the amps coming from the mower generator that will keep my battery charged up? I looked it up, but don't think my meter has a setting for that, or I don't understand how to set it for Amps. Will post picture of my meter if needed.

Thanks

The alternator on the Lawn-Boy uses the magnet in the flywheel. This means that it is generating a pulse of voltage as the magnet passes next to the alternator, and generates nothing for the rest of the revolution. Your meter, set for DC volts, is designed and calibrated to measure a continuous, steady voltage. This is why the voltage reading specification varies wildly from alternator part number to alternator part number (some are 18 VDC, some are 160 VDC equipped with the same battery!) and why they want you to use their "Lawn-Boy" meter.. So the DC you see shouldn't worry you - long as you got some you should be good.

I doubt if I'd worry about it, but a more reasonable check would be to check the battery voltage before you start, run the starter to discharge the battery some, and then check it again after you're done mowing. The voltage should be lower after you run the starter and higher after you're done mowing (probably near the pre-start voltage)..

Joe Kuhn said:

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The volts coming from the generator in this mower is 45 although the battery is 12. Is that a problem? If so, perhaps I need a new generator and perhaps it toasted the original battery.

How do I check the amps coming from the mower generator that will keep my battery charged up? I looked it up, but don't think my meter has a setting for that, or I don't understand how to set it for Amps. Will post picture of my meter if needed.

Thanks

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Generally you would use a 1Ω resistor connected to the battery and measure the voltage drop between each end ( called a shunt resistor & available from any electronics store )
Most of the mower engine companies also sell them as a service tool .
You can buy a cheap motorcycle amp meter and hook it up to one side of the battery .

However to do it properly you need some very expensive testing gear because you are trying to read a pulsed output which goes from 0 to a peak voltage then back to 0 then to a negative peak voltage then back to 0 V again

Bert: The alternator current has to be going through a rectifier (probably full-wave) or it wouldn't charge the battery since the negative pulse would counter the positive one.

John, As Bert said, due to the simplistic design (~3000 Hz pulse) it's not practical at all to measure with equipment you have around. Besides the shunt (the current is so low I'd use a 10 Ohm, BTW), you'd need an oscilloscope and a calculator/differential calculus. It's just not worth messing with at all. If your battery isn't getting kept charged, put it on a cheap 12V trickle charger once in a while. BTW, the early electric start Lawn-Boys didn't have an alternator, they came with a trickle charger for when the battery got too low, heh heh.

Fuzzy,
I know how they work , I was just trying to explain why he was getting silly readings.
Lots of mowers only use a 1/2 wave rectifier with no regulation so you can get really weird readings with cheap meters.
I am always dissapointed with how bad the knowledge of simple electrical principles is throughout the entire population

"I am always dissapointed with how bad the knowledge of simple electrical principles is throughout the entire population"

Couldn't agree with you more.

Now I feel bad for asking...

Joe Kuhn said:

Now I feel bad for asking...

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You should feel good Joe.
You now know more than you did before and that is the whole point of living
What is dissapointing is the schooling system did not prepare you for dealing with the modern world.

bertsmobile1 said:

You should feel good Joe.
You now know more than you did before and that is the whole point of living
What is dissapointing is the schooling system did not prepare you for dealing with the modern world.

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I know what you mean about the school system. My father had to teach me how to read in first grade by showing me how to sound out words. Identifying consonants and diphthongs didn't work. See "Teach Your Child to Read in 100 Easy Lessons" for the way it can be done right. And then there's the spelling issue... It is disappointing. I'm thankful for spell-checkers.

I've made it a point to fix machines with the owners helping so they can learn something about their machines. One guy continues to overfill his oil, but many others enjoy it and ask questions. Since turning 60, my point of living is in the giving. Here's my card:

Thanks to you both for the help. I'll be doing the after/after test:

> The voltage should be lower after you run the starter and higher after you're done mowing (probably near the pre-start voltage)...

Or maybe I'll just use the mower. It seems to be charged up just fine every time I start it. We're good to go.

No, Joe. I feel bad for agreeing with Bert. I'm sure there are plenty of things you know better than I. And that's what we're here for - to help each other. Don't hesitate a second to ask questions!