Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hey guys,

I'm officially done tinkering on my Eachine Microcosm ETX/M91 hit & miss engine. For anyone out there struggling with getting it to run properly like I did, I am listing the different things that I did to get it to where it is today. It will tick over like in the below video all day long, or at  least until the tank runs dry. And boy is it fun to just sit and watch it do that

- Replaced the cam follower bearing. It arrived broken from transport. I replaced it with a locally acquired sealed bearing.
- Improved the flywheel attachments. A simple grub screw just doesn't cut it. Drilled center holes in the crankshaft for them to screw into and stay in place. In the end I also used thread locker to keep them in place. So far so good.
- Installed an extra grub screw in the small cam gear to keep it in place.
- Made small timing marks on the cam gears with the Dremel to help in adjustment.
- Removed some material from the governor lever. It would hit the cam gear while running.
- Made new crankshaft bearings to get rid of crankshaft radial and axial play.
- Lapped both inlet and exhaust valves to improve compression.
- Adjusted exhaust valve timing to stay open a little longer.
- Adjusted ignition timing to just slightly before TDC for stronger 'hit'.
- Replaced the spark plug cover. The original one allowed spark to literally go through it to ground causing intermittent spark.
- Replace the spark plug itself. This was a game changer. It made a huge improvement. The original one was apparently very low quality. I installed a Japanese one and it solved most problems as to unreliable spark.
- Replaced the ignition batteries with a single LIPO cell.
- Fabricated a bigger knob on the mixture needle so I could actually see what I was doing.
- And finally I experimented with different spring on the governor. The ones I'm using now I harvested from an old RC Transmitter.

I probably forgot some stuff that I did....but I had a lot of fun doing it. And as I said the engine runs reliably now. Compression improved dramatically over the time I tinkered with it, from the valve lapping but also from running in I guess. I'm running on Alkylate fuel as suggested by Raphael. Hardly any fumes / smoke. This is one great little engine.

So after all this I'm happy to show you all the result:

This is simply excellent!

Thanks for sharing all your hard-won knowledge on how to get these little gems to perform so well!!

Just what this Forum is all about!!!

Bonjour hdebruin,

You have definitely made a great job, bravo ! Mine had also a lot of issues, but with my friend, we have not made all your enhancements.
Yours runs perfectly smoothly, mine would need your skills , you can hear the difference :

Bonjour Hans,

Thank you for your feedback, the spark plugs are 1/4-32 aren't they ?

Have you got a reference to share with us, I just find only complete ignition systems ?

Bonjour Hans,

Not found in France either, I have used your link, many thanks one more