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

The  m91 engine arrived today from enginediy.com.
Or rather I’d almost want to call it an engine kit. It certainly wasn’t ready to run out of the box.
It’s a long four hours from first fuel up to successfully starting, running happily, and restarting reacily. I’ll just hit the main points.

The compression is a whole bunch better when the spark plug isn’t loose.  The ignition is much more reliable when the high tension lead is stripped a bit at he end, rather than cut square.

The loose engine mounting screws came in handy when I disassembled the cooling system and pulled the engine off it’s metal base plate to access the fuel tank mount screws, which were loose enough that the tank was flapping in the breeze.
By that point I was referring to it as my engine kit. It’s not real obvious how the radiator is mounted. It’s real obvious the fuel tank bracket mount screws are impossible to access without removing the radiator, which I now know means splitting the engine from the mount plate. Fun stuff. 

Last but not least, yes, these engines are tough on batteries, especially when you forget to turn the ignition off.

Maybe we can take up a collection and send Jin a bottle of low temp, Easy disassembly type lock tite.  They’ve obviously not been introduced.

It starts and runs fine now and is delightful to listen to.  It’s still running fast on the stock governor springs, but hits and misses nicely.
First order of business will be a longer, wider, weighted  base to replace the original box, and allow for battery  change from the top side.

Just so I understand, Jin is supposed to be the designer of these engines from what I gather. I’ve seen a bunch of videos, a few of Jin’s, including his motorboat using the M91. Ive seen the unboxing and start up of Jin’s #1 and #2 M 91, as well as a video of #3.
I’ve heard microcosm and banggood.com mentioned as sources. Someone read the instructions sheet aloud, and showed it in the video.  All of that squares with the engines all coming from a single source, but literally dozens of resellers, websites and eBay resellers and amazon, all have the same engine, with the sane description and specs, including the curious use of “itinerary” for the piston stroke dimension. Prices vary from the $370 ish range to around $500. Yet as far as I can see, they’re all the same critter. How exactly they’re made and by who is unknown, but a fair number are being offered in all manner of outlets.
So I read the replies regarding buying directly from Jin, and I appreciate the loyalty among friends, but come on now, are they or are they not the same critter, even M91, hand signed by Jin as  #2, the one with the bent crankshaft that showed no damage to the box.