I was hoping this was more of a hardware project as in building the physical mower from scratch. I am not quite sold on the robotic mowers but the quality and market for riding mowers is insane right now. I own two riding mowers and both are completely dead. One needs a rather expensive wiring harness so they it would stop catching fire when it runs. The other has the most common single cylinder engine that comes in all the mowers in the past like 30 years and it’s a terrible design that grenades itself 1-4 times a year. And the prices of these new and used are out of this world even compared to baseline inflation.
I decided to strip one of them and convert it to full electric using salvaged electric motors from Ryobi mowers and Amazon controllers. I have seen a few videos of this conversion and I do like the logic of having one motor for the drive wheels and one per blade rather than messing with fancy belts and pulleys and idlers and clutches. A really interesting part of this kind of build is that I can reuse Ryobi’s 40V batteries so I don’t need to design and build a custom battery + BMS + charging system. Just buy and wire enough connectors to run everything.
And that’s where it would be really cool to see a properly engineered project around doing something like that. I see a lot of potential here since you can get these motors for roughly $50 shipped on eBay and a controller would be about as much.
Using current state of tech parts, including US sourced batteries with 10 year performance guarantees, I designed a "clean sheet" electric UTV constructed with bio-composite materials that would put the John Deere Gator out of business. The NEV carve out is fascinating. I learned how to scale RC cars up so I look at this differently than Lincoln or Tesla thinking EV is a reason to stuff more and more and more things in it - simplicity is the best use case for EV.
I would love to hear more about this if you have information online anywhere.
I gave up on having an electric mower any time soon since I have a riding mower and a garden tractor that simply won't die. I really don't want to buy something new if I can keep repairing old stuff, no matter how annoying it gets.
However, I am interested in building an electric UTV in large part because it would be quieter than my Honda Foreman.
From what I gather you can measure inflation many different ways. It’s not an absolute value but more of an average of prices on some number of goods. Kind of like how there are many index funds having different mixes of securities.
This is as much a complaint about high prices as the fact that Briggs & Stratton keeps making and selling an engine with an absolutely awful design.
If you want the boring details: it is a single cylinder 4 stroke motor. The first issue is that while it is dead simple, it does not have a modern way to control the RPM. These motors are meant to run at roughly 3600 RPM but at full throttle (how they are meant to be operated once in use) they will easily exceed that especially with no load such as in neutral. So they have a mechanical governor, which is also combined with an oil slinger (exactly what it sounds like: it is just a thing that slings oil all over the place hoping to get it onto the parts that need it). This contraption looks like this: https://www.lawnmowerpros.com/prodimages/691968.jpg. It is not very sturdy and is not very well mounted. It tends to break or even jam the gears between the crankshaft and the camshaft. This is bad because you don’t want loose pieces flying inside the bottom end of the motor.
In addition these motors have puny starters, so they have what’s called a compression release, which is a weight and a spring on the cam shaft. You can see it right by the gear here: https://www.briggsbits.co.uk/acatalog/84005207.3.jpeg
The idea is that at low RPM such as while you start the engine, the tiny spring will hold the weight to the shaft and the bump on it will keep the exhaust valve slightly open. This will mean you don’t get normal combustion but also it will be a lot easier to turn the engine over which is important for the puny starter. At higher RPM the weight will fly out and the other side with the bump will retract causing the exhaust valve to close fully when necessary.
The issue with this design is that the spring as you can see is tiny and thin and the weight is also pretty flimsy. They tend to break off and then you have a chunk of metal again.
Speaking of the camshaft, notice that the cam lobes are pressed onto the camshaft, not cut out of a single piece of steel. This is cheap but tends to be very sloppy. These motors don’t run very well.
And lastly, while these motors have a (tiny) oil pump and it is properly driven by the camshaft, the part that drives the oil pump is actually a separate piece of shaft that just slots into the main shaft of the camshaft. You can see it here as the short shaft with two flat parts on either end: https://www.lsengineers.co.uk/media/catalog/product/cache/21...
This means the camshaft isn’t even straight necessarily but is gear driven which requires more precision than chain, not less.
This is before we get into just basics like the fact that none of them have proper head/cylinder mating surfaces so they blow head gaskets like crazy, or their very loose rockers that go out of spec all the time causing it to run very poorly and needing constant adjustment. This is the same exact engine in every smaller riding mower on the market today. If you don’t get this one, you will get a much worse Kohler equivalent.
An equivalent Honda engine I could swap into my mower would cost me $2,000 for a refurb. Harbor Freight used to sell a motor for this for $800 but discontented it a few years ago. Basically, the entire market segment is shit. Greenworks and Ryobi have the electric mowers for about $5,000 that don’t seem to have these issues but batteries don’t have nearly the energy density than the two gallon of gas which is what it takes to run a normal mower for an hour.
Is this a newer design? Asking because I have a 40-year-old Murray garden tractor with an 18hp 2-cylinder Briggs 4-stroke and while it's harder to start in winter now (snowblower duty), it doesn't show any sign of dying soon.
This is the Intek single cylinder 500cc that is rated for 16-18hp depending on who you get it from (though internally they are all the same). I do think it is newer but not that new. Their V twins are apparently a bit more bulletproof though I haven’t taken mine apart to check. That’s the one that catches fire now due to bad wiring.
Yes I am in the US but in so far as inflation is an overall increase in cost of goods and services, the tariffs are one contributing factor to it. How much of a factor is probably hard to tell but my gut feeling says in this case it is probably significant.
I decided to strip one of them and convert it to full electric using salvaged electric motors from Ryobi mowers and Amazon controllers. I have seen a few videos of this conversion and I do like the logic of having one motor for the drive wheels and one per blade rather than messing with fancy belts and pulleys and idlers and clutches. A really interesting part of this kind of build is that I can reuse Ryobi’s 40V batteries so I don’t need to design and build a custom battery + BMS + charging system. Just buy and wire enough connectors to run everything.
And that’s where it would be really cool to see a properly engineered project around doing something like that. I see a lot of potential here since you can get these motors for roughly $50 shipped on eBay and a controller would be about as much.