Lots of chainsawists here, I may be joining you some time, but first I’m looking for a simple way to put a chainsaw beyond use, without being obvious about it. I haven’t looked closely, but I assume it’s a small 2-stroke engine. Does sugar in the tank really work, and would it be easily diagnosed? Anything else that might be better?

The problem is, I have an elderly relative who clearly should not be allowed to use it. To my admittedly untrained eye, he’s an accident waiting to happen. No training, no protective equipment, yesterday he was chopping up a loose heap of branches, slipping around on a muddy slope, using his foot to try to hold the logs in place and cutting right next to his foot. Of course he won’t listen to criticism, he’s been doing it for decades this way (though only a couple of times a year). Maybe so, but he no longer has the coordination or reactions that he used to. The saw is some small cheapish thing, no chain brake (at least, I don’t think so, only got a quick glance at it), the bar works loose after a few mins use, etc etc. It’s a poor starter so would not be too suspicious if it just doesn’t work next time he gets it out.

The longer term plan is I’ll get a new saw and PPE and maybe a little bit of training and take over. He has a bit of woodland so it needs a little bit of looking after, not major tree felling but clearing fallen branches etc (and we burn the wood).

Just take it from him.
Why break it?
Edit: take the spark plug out

as above, if you have access why not just remove it?

leaving him with something that may or may not stop working when he’s halfway through a branch next time he uses it doesn’t sound too good?

aye, spark plug sounds best.
that or drain of fuel and take his fuel can away (though he’d probably just get some more…)

depends how clever he is. removed plug would be obvious immediately to most. cutting the ht lead or otherwise disabling the ignition would be obvious if you stuffed another plug into the cap to see if there was any sparks. you could put a hole in the carb diaphragm so it doesnt pump petrol, and or block the fuel line with something.

if you absolutely want to disable it remove the plug and drill a tiny hole in the piston and then put the plug back in.

if he has any mechanical sense at all though he should be able to fault find any of these in a couple of minutes.

Switch the fuel for non-premixed. It’ll run for about 5 minutes then sieze. At which point you can convinve him that he must have forgotten to add the oil/got the mix wrong, and maybe you should take over…

remove plug and push electrodes flat so its shorting out, then put plug back in.

on the LT Circuit a bit of clear Nail varnish on the Connections works wonders

all reversible just a pain in the butt

Take plug out and close the gap at the ignition end and then replace. When you inherit the saw, replace plug.

Just buy him a new saw and a saw horse. No need to be devious and underhand.

Lock it through the handle to something solid. Why break it, just be up front with the conversation afterwards.

He’s a lovely guy, I don’t want to start a big fight and he won’t accept me taking it off him – it’s his after all. But I do want the problem to go away. Spark plug is a good idea, thanks, I will try to damage it a little. Can’t just take out, he’s got his full set of marbles!

It might be 6 months or more before he even tries to use it again, and I’m sure he would be happy if I took over in the meantime – though he would wonder why I bothered with all that silly safety gear…

Put some plastic or similar inside the plug cap to stop electrical contact and stop the spark plug from working.
However have you thought that he might try to do the work manually which will be much more physical effort which has it’s own dangers?
I say this as my late father was in a similar-ish situation, he wasn’t a safety hazard though, the chainsaw enabled him to do what he wanted to do long after he would have done had he not had the saw.

Offer to get it serviced. Take it away to get it done.
Buy the PPE kit and saw horse. Do your 2 day chainsaw safety course. When the saw comes back from being serviced, offer to do the chopping for him as you need to practice what you learnt on your course.

He’s an adult and of sound mind – much as you like him, making his decisions for him isn’t right.

He’s an adult and of sound mind – much as you like him, making his decisions for him isn’t right.

Tis is the answer I think – he is an adult, he isn’t doing anything illegal.

Leave him alone, he’s only going to hurt himself (if anyone) and you are no expert, even if you were you’re not the chainsaw police.

If it were me I’d just try to beat him to it, so every time he thinks about getting the saw out there is no need as you’ve already cut and split the wood for him! It’s much easier to ‘do him a favour’ and cut the wood than try to be underhand and possibly upset him. If he asks why your doing it just say that you enjoy it, the fresh air does you good, the noise drown out the wife etc etc!!

As you say, he’s still got all his marbles.

Why not just talk to him about it.

Tell him you want to help him out, and even though you know he’s capable of doing it himself you want to help because you would feel awful if anything happened and you hadn’t been there to help.

He’s been doing it his way for decades as you said, and it’s not the easiest way, maybe if you learnt how to do it properly, he would appreciate the help and appreciate that there is an easier way to do it rather than slipping about holding stuff with his boot.

Plug out, feed length of string into hole onto top of piston and refit plug

Take the chain of and tell him its a new safety saw.

A friend of mine had a similar situation with her elderly mother driving.
Just because someone is legally entitled to do something and still physically capable of attempting it, it doesn’t mean they can do it safely.

Three options;
1. He is an adult. Let him make his own decisions.
2. He is not fully aware of the danger. Try to dissuade him, although this could be awkward.
3. He is not fully aware of the danger. Disable the saw before he disables himself.

As others have said, altering the plug gap is the easiest, non permanent, reversible way of stopping an engine.

Driving is different, you put others at risk. He’s got the right to take risks with his own wellbeing.

I hope you never see me using my chainsaw, you might decide i’m not to be allowed either.

Come to think of it, this is a bit of a moral dilemma.
Adults have responsibility for their children’s wellbeing, but at what point do you decide to take responsibility for an elderly relative, possibly against their will.

Should you hide your granddad’s fags and whiskey if it’s for his own good ?

at what point do you decide to take responsibility for an elderly relative, possibly against their will.

You don’t. People have the right to make bad decisions in my view.

Ppe the old bugger up and let him have his fun.

miserable stw nannies.

I wouldnt tamper with his chainsaw, if anything happened it would be your fault

Fill it with Diesel

Meddling with his saw is utterly disrespectful, what a bunch of idiots. Offer ppe, new saw, otherwise leave him to it. Imagine some jumped up fresh joker tried telling you how to mountain bike one day, tried messing with your bike because they want you to stop in case you hurt yourself… your mindset would be ‘whatever, if I get hurt I get hurt’ right?

On the other hand, and trying not to jump to conclusions about TheCaptains particular situation, what if your elderly relative starts showing signs of dementia ?
At what point do you step in and take charge of their life ?
Or do you just leave them to it until eventually they just wander off out one day and don’t come home because they’ve forgotten where they live ?

Mtg.. forgetting where you live is not a symptom of early dementia, unless youv just moved house.

OK, I was using an inaccurate stereotype, not a genuine symptom as an example.
The principle is the same though.
Someone who has spent a lifetime looking after themself is going to be reluctant to admit that they are no longer able to operate a gas cooker, car or chainsaw safely.

But…

The OP states

Of course he won’t listen to criticism, he’s been doing it for decades this way (though only a couple of times a year). Maybe so, but he no longer has the coordination or reactions that he used to.

So it isn’t a case that he has dementia or is somehow otherwise unable to operate it. To me it seems that the OP has decided that, despite the relative doing this for decades, they are no no longer able to do it for no other reason than because it looks dangerous and they are old.

Maybe it is dangerous and maybe they are old, but that isn’t a reason in itself to intervene.

If people are impaired to the point of being incapable of understanding the consequences of their actions then there are laws in place to deal with the situation while protecting their rights.

I have a friend who lives in the Highlands but is scared of the mountains. She can’t see any reason why people need to go up them so honestly believes hillwalking is a dangerous activity that should be banned. Luckily its not her decision.

MTG- car, dangerous to others, Gas explosion, dangerous to others, Chainsaw, dangerous to user, except Texas.

Thanks for the interesting range of views. I do have some sympathy with the “let him get on with it” point of view. No dementia and for his age (mid 80s) he’s amazingly fit and active, presumably in part becase he does keep on doing stuff. From a selfish POV however, it would be us looking after him if he did hurt himself – and he’d hate that. I’d also hate myself if I just sat there twiddlng my thumbs watching him cut his leg open. We did persuade him not to go climbing on the roof a few years ago, but he doesn’t see a chainsaw as being in the same league for danger.

Current plan is for me to press on with getting myself sorted to take over. Haven’t actually touched his saw yet, might not need to as we can probably deflect him if he talks about using it again soon.