How to start a 337

[Wayne Pearce]

I quite often fly from airfields with density alt of over 5000' in Australian bush and always approach at near full rich ready for go around and have never had a problem with cylinders or fouled plugs so I thought I should rethink this when reading this thread, this is what I came up with.............

*Always prime cold engine with 60lbs/hr fuel flow for one sec prior to start it will always start burnin & churnin within two revolutions

*Do same at 30lbs/hr with hot engine

*I quite often have to lean on climb above 5 or 6000' to keep the engine "tone" sounding correct

*I "gain control of the MP" and begin to enrichen prior to decent, I enrichen by 50'F before decent and keep it there until the circuit where on final I run nearly full rich depending on circuit density alt, this does not give thermal shock when done slowly

*If go around procedure is UP, UP & UP then I do not want to go from lean & hot upper cylinders to cold (thermal shock) just when I need full power. Saw a P68B damage a Lycoming 360 this way

*Have never had a problem with fouled plugs !!!!!!!!

*If we look at fuel line diameters and flows etc. we see that fuel velocity is around 520 mm/sec all things considered you are not going to heat the fuel appreciably with engine in the cruise getting fuel from a tank that is marginally above ambient because of return fuel

*vapour problems are either caused by low fuel flows & hot engine on the ground or cavitation or extreme temps where the fuel pressure is exceeded by vapour pressure

Hmmmm I am still rethinking my logic here whadya think

regards.............. Wayne

[Skymaster337B]

Speaking about starting procedures...the book mentions we should start the rear engine first. However, I start the front engine first because the battery is in the front. This saves the battery over time; so far, my battery has lasted almost 9 years now. Any one else do the same?

[Ernie Martin]

I always start the front first, but I thought that is what the book says. If I recall, it's because of the shorter run between the battery and the engine. If you happen to be in a highly marginal situation, where there is barely enough energy in the battery to barely turn an engine, then you want it to be the front engine, where you might get 3 or 4 revs before the battery dies, compared to the rear engine, where you might get 1 or 2 revs because of the higher cable resistance.

Ernie

[hharney]

My 1968 Owners Manual states that the front engine is normally started first. Rational is the battery cable length as Ernie states above.

I know I was always taught to start the front first and at one time I heard something about procedures indicating the rear should be started first because you can't see it and if the rear is started first you could hear it better.

But my book says the front should be started first.

[JeffAxel]

FWIW, they changed the wording in the first paragraph of the starting section in later POH's. My '77 POH says either engine can be started first, and mentions both arguments, the shorter cable run for the front versus the ability to hear the rear. I usually start the rear first, just because I like being able to hear it. If my battery was so drained that it couldn't start the rear engine, I would want to abort the flight, figure out why the battery was so low, and charge it properly with a charger, assuming the battery itself was okay. Recharging an almost dead battery with the alternators is tough on the battery and electrical system, and I am not sure I would feel comfortable relying on that system, especially in IFR or at night.

[Skymaster337B]

The only way we could resolve this topic is at the next Skymaster fly-in...at the hotel bar.

[skymstr02]

If you start the front engine first, how do you clear the rear engine?

I can yell "Clear Rear" thru the storm window, and some one will hear me, and then clear the front visually.

On my O-2, the battery is just inside the baggage door, so the rear starter is closer to the battery than a standard 337.