Kratmo 4A Repl.

This motor is a 2 stroke engine with .24 cu inch. It is equipped with an electric ignition system, and the original machine was constructed and built by Walter Kratzsch about 75 years ago, who created a whole “engine-family” of several gasoline and diesel types with different engine sizes:
The 4A is the little brother of the famous Kratmo 10A. –
Logically there are only very few original engines left today; all in property of model-engine-collectors, who usually store those engines in a glass case…
The replica of this engine I have reproduced in facsimile to the original machine with a small constructive concession for easy use: I replaced the sensitive contact –ignition with a maintenance-free transistor-system - by maintaining the ignition advance:
This engine is no historic “sensible”, but a reliable solution for daily use:
So every ambitioned builder of smaller antique model airplanes has now the possibility to motorize his model adequately insound and optic with this special engine…


Size: 4,07 ccm or .24 cu inch
Bore: 18 mm
Stroke: 16 mm
Weight: 220 g
Output: 5200 rpm with a 11” x 6” Forte-Woodprop.

Kratmo 4A without ignition system -- 300. - €
Ignition system for Kratmo 4A -- 70. - €

For ambitioned home builders, a set of cast parts for the Kratmo 4A is also available now:
The set I can offer, includes the raw parts for crankcase, crankcase-cover, spinner, connecting rod, prints of CAD drawings with a stock list and a raw piston made by using a special aluminium alloy.
For building the Kratmo 4A a small engine lathe and fundamental experience in metal processing are required. –
It isn’t necessary to install an ignition system, as the Kratmo 4A can also be run with a normal glow plug and methanol-castor-mix.

Set of cast parts with CAD drawing: 49, - €
Material for cylinder, crankshaft and bearings: 17, - €
Sparking Plug with 1/4" x 32g thread: 19,50 €