Does this mower mod really work as shown?

Ben08 · Sep 27, 2019

I watched it, and it seems like it would work, but I don't know. Please let me know, because I'm thinking about doing what's show to one of my older mowers. Thanks guys!

https://www.youtube.com/watch?v=fIc0dkJ7Xzo

4getgto · Sep 27, 2019

Cool idea but I think I'd just go to HF or somewhere else and buy a cheapie 120v unit for $30 or less. Lot easier.

bertsmobile1 · Sep 27, 2019

This idea has been around for most of the 20th century so nothing new or even clever about it.
Popular mechanics ran a story about doing it then quickly retracted the story in the following issue after the dangers were made apparent to the people who have no fundamential understanding of how 4 cycle engines work.

Decades ago a similar device was marketed for 4 WD adventure touring.
It replaced a spark plug.
Finally it got banned after dozens of people died using it.
Some emergency vehicles still use them and as a last ditch get you out of a potential death situation they are OK but not & never will be a replacement for a proper compressor.
Considering you can buy 12 plug in compressors for under $ 10 why bother with some thing like this.
It will cost more to make than buying a small 12V plug in.
I have a 1/2 dozen battery starter packs with a built in compressor . a far more useful device than this trash.

Despite the charcoal filter the bulk of the fuel will pass into whatever you are inflating effectively making it a bomb.

Remember that on compression stroke you are pumping unburned air/fuel mixture into your tyre
Then on the following power stroke you are pumping the burning fuel air mix then plain exhaust into your tyre.
Exhaust is very hot so the whole shebang will get to very near muffler temperature so there is a burn potential.
Exhaust gas pressure is in the order of 1400 psi so the system would get a 100-140 psi charge from the compression followed by a 1400 psi pressure pulse from the combustion.

The poster is an idiot moron fool and is encouraging others to risk serious injury for absolutely no benefit.

Even making a compressor by converting an old engine into a pump and powering it with another engine does not work particularly well and there are thousands of videos about how to do that.
Compressed air is very dangerous , in fact compresses any gas is dangerous and fooling around with some thing that your do not understand is a sure fire way to spend a holiday laying on your back in the ICU ward of your local hospital.

Romore · Sep 27, 2019

X2! The guy has too much time on his hands. Without some form of regulator that is going to blow the tire and spew hot fuel/air mix at the operator. I remember working on a Schramm compressor, it was a 6 cylinder engine which ran on 3 and pumped air with the other 3. The pushrods had been removed and and spring loaded poppets replaced the valves. The intake and manifolds were split. It worked but ran like a hit and miss.

Ben08 · Sep 28, 2019

bertsmobile1 said:
This idea has been around for most of the 20th century so nothing new or even clever about it.
Popular mechanics ran a story about doing it then quickly retracted the story in the following issue after the dangers were made apparent to the people who have no fundamential understanding of how 4 cycle engines work.

Decades ago a similar device was marketed for 4 WD adventure touring.
It replaced a spark plug.
Finally it got banned after dozens of people died using it.
Some emergency vehicles still use them and as a last ditch get you out of a potential death situation they are OK but not & never will be a replacement for a proper compressor.
Considering you can buy 12 plug in compressors for under $ 10 why bother with some thing like this.
It will cost more to make than buying a small 12V plug in.
I have a 1/2 dozen battery starter packs with a built in compressor . a far more useful device than this trash.

Despite the charcoal filter the bulk of the fuel will pass into whatever you are inflating effectively making it a bomb.

Remember that on compression stroke you are pumping unburned air/fuel mixture into your tyre
Then on the following power stroke you are pumping the burning fuel air mix then plain exhaust into your tyre.
Exhaust is very hot so the whole shebang will get to very near muffler temperature so there is a burn potential.
Exhaust gas pressure is in the order of 1400 psi so the system would get a 100-140 psi charge from the compression followed by a 1400 psi pressure pulse from the combustion.

The poster is an idiot moron fool and is encouraging others to risk serious injury for absolutely no benefit.

Even making a compressor by converting an old engine into a pump and powering it with another engine does not work particularly well and there are thousands of videos about how to do that.
Compressed air is very dangerous , in fact compresses any gas is dangerous and fooling around with some thing that your do not understand is a sure fire way to spend a holiday laying on your back in the ICU ward of your local hospital.

Thanks for the detailed reply! I messaged the video creator and provided a link to this thread. He said you're right, but underestimated what he did. When he modified the check valve, he applied air pressure to the valve to see at what pressure it starts to open. It was done by tightening the valve against the spring as it threads on. He set the opening pressure at 110PSI, which is 10PSI higher than the engine compression. By doing that, you get the pressure from the explosion, not the compression stroke. Any small amounts of fuel vapors that make it through, should be taken care of by the activated carbon filter. He changed the video title to "Experiment", and added disclaimers to discourage people from trying it.

bertsmobile1 · Sep 28, 2019

Well at least he has a moral conscience if nothing else.
Putting exhaust into any thing rubber is not a good idea.
Water pipe is rated at 250 psi ( well down here it is ) .
Now I appreciate that he put a restrictor valve in there but still not a good idea.
Was not a good one 80 years ago and still not a good one today.

Also he is using a spring & ball check valve when they get hot the spring pressure drops unless he is using high temperature nickel steel springs ( expensive ).
There is a lot of things you can do if you put enough time & effort into it .
The question is , why bother & is it a fruitful use of ones time ?
We have a charity down here which is crying out for inventive people to modify every day items to make them useable by people with dissabilities.
I am sure there are similar organizations over there and his time & inventiveness would be better spent there.

To the costs you should aso add the price of an exhaust gasket because drilling & taping a cylinder head in situ is also very bad practice.

tom3 · Sep 28, 2019

Looks like a fun project. But... The flat head Briggs has about 110 psi compression, what happens when the F/A mixture explodes. Nothing in his rigging is rated at over 125 WOG, nor rated for extreme temperatures. I'll stick with a compressor or air tank. Can get a jump box these days with a built in compressor for $75, much cheaper than a trip to the ER.

SeniorCitizen · Sep 28, 2019

I used this one to air Model A tires when I was a kid. With a 2 cyl mower engine just remove 1 spark plug, screw in the adapter and you have a compressor.

bertsmobile1 · Sep 29, 2019

Gees you must be nearly as old as I am.
but yes like was mentioned before nothing new or exciting.

Does this mower mod really work as shown?

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