Vacuum pump from lawn mower engine ??

[gbatten]

Have any of you ever heard of making a compressor /vacuum pump from a small (+/- 3 Hp) lawn mower engine? It might work like this. Remove the carburator and muffler so the intake and exhaust ports are exposed. Attach a couple of straight pipes to the exhaust and intake ports with appropriate hardware. Turn the lawn mower engine with an electric motor using a V-belt and pulley attached to the drive shaft. As the piston moves up and down in the motor, it will pull air in through the intake port and push it out the exhaust port. As I can see it, the only "problem" with this home made system is the extra work done during the compression stroke. But I suppose some of that work is "recovered" on the down stroke. Any comments? Has anyone here tried this?

[paco]

A question; what kind of electric motor would this need?

[steve4460]

Hi guys

There was a guy on ebay a while ago that sold plans to convert a lawnmower engine in to a compressor. As to the motor it might not not take much of one since a 12V starter motor can turn it over to start it .
Sounds interesting .

[lto]

Or........

You could just continue pulling the starter rope.

Realisticly, don't expect the same amount of vacuum CFM's per HP as from a pump designed for the purpose.

[gbatten]

Obviously, this would not be as good as having a "real" vacuum pump or compressor. But, it might be a fun project if you have access to an old lawn mower engine, an electric motor and a few parts. Many of us "Shopbotters" like to "tinker", so I see this project in that category. As far as electric motor size, I think a 1/2 Hp 120 Vac should work fine. Actually, most any size would work so long as the pulley ratios are appropriate. Compared to a typical piston type compressor, the lawn mower piston is large, therefore, it should not be necessary to turn the motor very fast in order to achieve workable results. .. I have not tried this yet. It is just a "thought" project that is bouncing around in my head.

[Brady Watson]

You wouldn't have much CFM...a number of years back someone sold a conversion kit for a VW to use 2 cyl for power and the other 2 as an air compressor pump...pretty neat if you need a portable compressor.

-B

[mnrite]

I have an old compressor that I use (with a 1/2" plastic hose attached to the suction side) when I need a better vacumn than my shopvac. Low CFM but a much stronger vacumn.

Thanks
Mike