Diagnosing my lawn mower...

[Externet]

Hello all.

It works, satisfactorily, but the engine seems running roughly, and decided to investigate.

The way it works is with a thermal choke fully applied when cold (bimetal spiral) heated by the exhaust opening the choke gradually.  That operates fine from cold to hot, fully closed butterfly to fully open in a couple of minutes.  No manual choke, no priming bulb, no manual speed control.

But noticed than in the middle of the transition, there is a point where the choke butterfly wildly and widely closes and opens, like synchronized to every air intake pulse, like actuated by the air flow and not by the thermal bimetal.

Looking at clues from web forums and youtuber geniuses, they guess one thing after the other until sort of make them work.

The choke butterfly is asymmetrical, for too much suction, air flow pushes its larger 'half' in to force open. 

None of the repair experts mentioned that behavior.

What would you do / opinion ?    -images borrowed from the web-

 

[iNow]

2 hours ago, Externet said:

What would you do

I’d start by disassembling, cleaning, then reassembling it and trying again. I’d also give it fresh gas, new plugs, and new filters. 

[dimreepr]

10 hours ago, Externet said:

It works, satisfactorily, but the engine seems running roughly, and decided to investigate.

Have you asked the manufacturer? Maybe that's how it's meant to run, if it works, satisfactorily.

If it was me I'd just use it, until it doesn't work and then I'd investigate, but then I'm a lazy bugger... 😴 

Edited May 6, 2023 by dimreepr

[Sensei]

..it's still too early to get the lawn mower out of the garage..

Let the grass grow..

 

One of the most annoying things here in spring and summer is mowing the lawn.

Design a quiet/soundless lawnmower and you will become a millionaire.

Apart from changes in the engine etc., I was thinking about (recording and) emitting anti-sound. https://en.wikipedia.org/wiki/Active_noise_control

 

[TheVat]

Once fixed a cranky butterfly valve on a Dodge Colt with a paperclip slipped on it. Maybe not applicable to this, though.

I switched to electric about 1985, and life was so much better.  People hate the corded ones, but they are so much better than mucking around with the crappy batteries on the cordless ones that the mfr. claims will take 2000 charges and you are lucky to get 200 before they fail completely.  And the cutting power is weak.  And the batteries are the most expensive part of a cordless mower, so every four-five years you have to spend a ton of money to replace them.  Corded mowers, however, last for eternity.  My dad had a Black and Decker corded mower for forty years, from around early 70s, and it was in fine condition when I donated it to a Habitat store after his death.  It is not difficult to develop a mowing pattern that keeps you from running over the cord.   Really.

[Externet]

5 hours ago, Sensei said:

Design a quiet/soundless lawnmower and you will become a millionaire.

Naaaahhhh... To become a multi-millionaire, design a GMO grass that does not grow over 2 inches, forget about the mower...

[Externet]

1 hour ago, TheVat said:

the batteries are the most expensive part of a cordless mower

The only thing they care about is to wring your wallet, not to provide performing equipment.  The day they put user replaceable non-proprietary batteries on a mower, then I will buy.

My cordless weeder batteries did not last even 100 charges. 😡

[Sensei]

1 hour ago, Externet said:

Naaaahhhh... To become a multi-millionaire, design a GMO grass that does not grow over 2 inches, forget about the mower...

But that way you won't have the smell of freshly cut grass, which is nice..

I have a brilliant idea - rotating laser and mirrors on the edges of the field..

Actually, this would also work well on a regular farm if you need to quickly cut an entire flat field..

Advantages 1) quick 2) noiseless 3) jobless lawn mowers..

[StringJunky]

Corded appliances are the pits where they have to be moved and manipulated. I get 2 or 3 years out of Makita or Bosch Green batteries, which are the tool systems I've bought into.

Don't know about unleaded rules over the pond, but we have gone on to E10 petrol/gas, which is not great for engines. The petrol will absorb more water in storage. I use a petrol preservative to mitigate it. 

Edited May 6, 2023 by StringJunky

[Externet]

The fresh smell of grass is matter of tastes.

Your brilliant idea https://www.youtube.com/watch?v=WTPHsouuGq4  carries an expensive liability insurance.   When I attemped a similar to stop ducks in shrimp farm ponds, no laser manufacturer came with anything.

 

[npts2020]

6 hours ago, Sensei said:

But that way you won't have the smell of freshly cut grass, which is nice..

I have a brilliant idea - rotating laser and mirrors on the edges of the field..

Actually, this would also work well on a regular farm if you need to quickly cut an entire flat field..

Advantages 1) quick 2) noiseless 3) jobless lawn mowers..

Disadvantage 1; seems to me a laser would cauterize the grass as it cuts so no fresh mowed grass smell. 

                        2; could be a fire hazard.

                        3; few fields are flat enough.

[zapatos]

14 hours ago, Sensei said:

...it's still too early to get the lawn mower out of the garage..

Let the grass grow..

Quote

No Mow May was started in 2019 by citizen scientists in the United Kingdom as part of a conservation study to support struggling pollinators. Homeowners were encouraged to leave their lawn mowers in storage through the month of May and allow their lawn weeds to grow and bloom. The idea was that participants’ lawns could then produce essential pollen and nectar for bees and other pollinators during the critical period in which they were emerging from hibernation.

Results in the U.K.’s initial study included a massive increase in floral diversity when these beneficial bugs need it most. A year later, residents of Appleton, Wisconsin, organized their own No Mow May, and the results were impressive. Researchers reported a threefold increase in bee species diversity and a fivefold increase in the number of bees in no-mow yards compared with neighboring yards that were mowed as usual. Since then, the movement has gained a life of its own, with supporters and opponents trumpeting an endless string of social media hype, opinions, and pseudo-science.

https://www.bobvila.com/articles/lawn-no-mow-may/#:~:text=A year later%2C residents of,that were mowed as usual.

[mistermack]

On 5/6/2023 at 1:46 AM, Externet said:

t works, satisfactorily, but the engine seems running roughly, and decided to investigate

Since it starts ok, I would just let it warm up, and then jam the choke open. You could rig up a cable to do it manually. 

[dimreepr]

11 hours ago, zapatos said:

https://www.bobvila.com/articles/lawn-no-mow-may/#:~:text=A year later%2C residents of,that were mowed as usual.

But don't worry, it'll probably start in June...

[J.C.MacSwell]

On 5/6/2023 at 11:24 PM, zapatos said:

https://www.bobvila.com/articles/lawn-no-mow-may/#:~:text=A year later%2C residents of,that were mowed as usual.

Started that last year...or at least started using that as a convenient excuse not to mow before June...

[zapatos]

36 minutes ago, J.C.MacSwell said:

Started that last year...or at least started using that as a convenient excuse not to mow before June...

We started a couple of years ago too. Soft Landings are another good way to cut down on mowing that we've incorporated into our yard.

Quote

Soft landings are diverse native plantings under keystone trees (or any other regionally appropriate native tree). These plantings provide critical shelter and habitat for one or more life cycle stages of moths, butterflies, and beneficial insects.

https://www.pollinatorsnativeplants.com/softlandings.html

[toucana]

On 5/6/2023 at 5:35 PM, TheVat said:

Once fixed a cranky butterfly valve on a Dodge Colt with a paperclip slipped on it. Maybe not applicable to this, though.

I switched to electric about 1985, and life was so much better.  People hate the corded ones, but they are so much better than mucking around with the crappy batteries on the cordless ones that the mfr. claims will take 2000 charges and you are lucky to get 200 before they fail completely.  And the cutting power is weak.  And the batteries are the most expensive part of a cordless mower, so every four-five years you have to spend a ton of money to replace them.  Corded mowers, however, last for eternity.  My dad had a Black and Decker corded mower for forty years, from around early 70s, and it was in fine condition when I donated it to a Habitat store after his death.  It is not difficult to develop a mowing pattern that keeps you from running over the cord.   Really.

If you use a corded mower or hedge-trimmer in your garden, please remember to run the mains supply cable via an RCD (residual current device) aka a GFI (ground fault interrupter) in the US - preferably one with a 30mA tripping threshold.

https://en.wikipedia.org/wiki/Residual-current_device

These are often built into the type of cable extension reels used by handymen, or can be purchased as plug-in modules. They work by comparing the current flowing on the live and neutral sides of the supply by means of a balance transformer, along with a trip that disconnects the power instantly if an imbalance greater than 30mA is detected. This prevents a potentially fatal shock in a way that a simple over-current device cannot (fuses and thermal trips can take many seconds and even minutes to blow).

[TheVat]

22 hours ago, toucana said:

If you use a corded mower or hedge-trimmer in your garden, please remember to run the mains supply cable via an RCD (residual current device) aka a GFI (ground fault interrupter) in the US

I don't know anyone who has used GFI protection with a mower.  Nor have I heard of anyone being electrocuted by their mower.  It's difficult for me to imagine how your body, gripping the plastic handle and deadman switch, could find itself as the current pathway.  That said, How Can I Electrocute Myself with my Lawn Mower sounds like a great thread topic at SFN.  😀

[geordief]

15 minutes ago, TheVat said:

I don't know anyone who has used GFI protection with a mower.  Nor have I heard of anyone being electrocuted by their mower.  It's difficult for me to imagine how your body, gripping the plastic handle and deadman switch, could find itself as the current pathway.  That said, How Can I Electrocute Myself with my Lawn Mower sounds like a great thread topic at SFN.  😀

Yes I met someone who was electrocuted by their own lawnmower.

He was working in his bare feet and the cable was pulled out  of its socket ,landing in his hand

 

Luckily he was able to pull the   live lead from the affected and cramped  hand using the other hand but it lasted a long time .

 

Knew someone else electrocuted by their kettle in a similar way.

[StringJunky]

I had a cousin in Australia who was killed by electrocution from a faulty lawnmower fifty or so years ago.

[TheVat]

Either American lawnmowers are safer, or I've apparently led a sheltered life.  I will certainly not be using mine barefoot (which I always saw as kind of a no-no, given the proximity to whirling steel blades).  Sorry about your cousin @StringJunky.  

[StringJunky]

1 hour ago, TheVat said:

Either American lawnmowers are safer, or I've apparently led a sheltered life.  I will certainly not be using mine barefoot (which I always saw as kind of a no-no, given the proximity to whirling steel blades).  Sorry about your cousin @StringJunky.  

In those days, lawnmowers didn't have dead-mans handles and other safety features. Stuff that is plastic now were probably metal then.

[mistermack]

I've been nearly killed twice by electrocution. The first time was in 1953, when I was 3, my brother was six, and my mother told him to get the one-bar electric fire and plug it in to warm the dining room for tea-time. I had a tantrum, I wanted to do it, but my brother wouldn't let me, and I had hold of the bar, through the grill, and he just plugged it in. If you haven't experienced the full 240 volts, you will have no idea of the incredible power that goes through. The electric current caused my muscles to contract in my hand, so I couldn't let go. All I could do was scream, and bounce around the room. And instead of pulling the plug out, my brother went to my mother and told her I was screaming. By the time she pulled the plug out, the fire had heated up, and my hand was fused to it. Pure horror.

That's what a lot of people don't realise. If you get a shock through your hand holding something, you won't be able to let go, and chances are you're going to die. It's still my earliest memory, a miracle I didn't die.

[toucana]

On 5/21/2023 at 9:41 PM, mistermack said:

I've been nearly killed twice by electrocution. The first time was in 1953, when I was 3, my brother was six, and my mother told him to get the one-bar electric fire and plug it in to warm the dining room for tea-time. I had a tantrum, I wanted to do it, but my brother wouldn't let me, and I had hold of the bar, through the grill, and he just plugged it in. If you haven't experienced the full 240 volts, you will have no idea of the incredible power that goes through. The electric current caused my muscles to contract in my hand, so I couldn't let go. All I could do was scream, and bounce around the room. And instead of pulling the plug out, my brother went to my mother and told her I was screaming. By the time she pulled the plug out, the fire had heated up, and my hand was fused to it. Pure horror.

That's what a lot of people don't realise. If you get a shock through your hand holding something, you won't be able to let go, and chances are you're going to die. It's still my earliest memory, a miracle I didn't die.

I nearly electrocuted myself at age 2 by sticking a pair of copper rods into a power socket and switching on - blew the ring main out. I subsequently worked for quite a number of years as a theatre lighting electrician rigging 3-phase power 6.5 metres up in the air (double jeopardy - if the shock doesn't kill you, being thrown off the scaffold tower will) - so I'm probably a little wary of electrical shock hazards.

On the subject of lawnmowers - My wife was recently using a corded hedge-trimmer in our front garden, and quite neatly sheared clean through her own power cable. It was a 230 VAC supply being fed via a 30mA RCD which cut out instantly. It was a nuisance having to replace and re-terminate the supply cable - but a lot simpler than replacing my wife !

[mistermack]

The second time I was nearly killed was when I was about thirty, I was in partnership with a friend in some property, and he had wired the plug on a deep freeze that we kept in the cellar. I went down one morning to get some bread for toast, in bare feet on a dampish brick floor. Not looking at what I was doing saved my life. Instead of grabbing the lid handle, I missed, and just slightly skimmed it with the tip of my little finger. I got the full 240 volts, through the finger, up the arm, down the body and through my feet. Even though it was just a tiny fraction of a second, I was nearly poll-axed. 

He hadn't tightened the cord-grip on the cable where it enters the plug. Someone had pulled the lead by the plug to reach the socket on the wall, and so doing had pulled out the earth lead, and it was just resting alongside the live wire, so the whole freezer was live, just waiting for someone to touch it. 

That's a weakness in in having an earth cable that a lot of people aren't aware of. It's great, when wired properly, but a potential death trap if the cord grip is not properly gripping as it should.

Needless to say, I'm very thorough when wiring plugs, I go over the top, to make sure I never kill anyone by carelessness.