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By Kemble Pitts
Long shot I suspect given the scarcity of the engine.

I've been flying a Menasco C4S engined aeroplane and starting is pretty hit and miss (quite a lot of miss actually) and am hoping somebody might have experience of resolving starting issues with this engine.

Yesterday we put a hot air gun pointing into the cooling air intake for an hour or so before taking the aeroplane out of the hangar. A cold day but it started after a couple of blades (self-starter).

Flew for 40 minutes then had a break for an hour and a half or so and went to fly again. Although not stone cold it was a complete bar-stool to start. Lots of priming and lots of cranking, had to pug an aux battery in to keep trying. Hardly a puff. Eventually it went and we flew.

Primer is working, plugs are fine and the mags (Bendix) are OK but...

... the impulse is intermittent. The mags were overhauled about 50 hours ago and the impulse mag was removed last week and checked for correct operation. It works fine on the bench and 'impulsed' every blade when re-fitted (a few days before we tried a ground run, delayed due weather).

... and then it 'impulses' only about 1 in 4 blades yesterday when we first started and flew it. Even 1 impulse in 4 blades on a warmish engine should be OK!

Apart from the obvious 'make the impulse work reliably' (which we are still scratching our heads over) has anybody had experience of starting issues on this type of engine that they managed to resolve? If so, how?