The Cessna 120-140 Association Forum

I would be interested in starting techniques for starting engines when hot..

Here in the UK todays temp was around 30C (unusual I know) and with an oil temp of 140 my C85 refused to start until the temp dropped to below 100.

All advice gratefully received.

Many thanks

If the engine is hot, don’t prime it. If it cranks and refuses to start, I could be flooded. Open the throttle half to all they and crank. When it fires pull the throttle back to idle. Works for me!

In regards priming, I was having a problem where the mixture would not shut the 0-200 down. I had to use the mags. On top of that the idle was poor. I found the trouble shooting guide for the Marvel carb and for both problems they listed leaking primer. I disconnected and capped off the primer line and sure enough, both problems solved. I can start it both hot and cold with no priming at all, just a quick pump of the throttle and back to idle position and she fires right up and shuts down with the mixture now and idles nice and smooth.

8474 wrote: ↑Sat Jun 29, 2019 9:15 pm In regards priming, I was having a problem where the mixture would not shut the 0-200 down. I had to use the mags. On top of that the idle was poor. I found the trouble shooting guide for the Marvel carb and for both problems they listed leaking primer. I disconnected and capped off the primer line and sure enough, both problems solved. I can start it both hot and cold with no priming at all, just a quick pump of the throttle and back to idle position and she fires right up and shuts down with the mixture now and idles nice and smooth.

I'd recommend that you get the primer fixed. Lot less expensive in the long run especially after an engine fire during start up which can happen by pumping the throttle to work the accelerator pump on engines equipped with a Marvel Schebler carburetor such as found on an 0-200.

If you have a carb with an accelerator pump, don’t stroke the throttle. If it doesn’t start initially with the throttle cracked open slightly, move the throttle in slowly until it finds the point where it starts and be ready to pull back to a slower speed when it does. If it has no accelerator pump, start moving the throttle forward when you begin hitting the starter.

Either way, this is a two handed operation.

I should have said "short" pump instead of quick. I didn't mean a full travel pump, just a short, less than an inch movement. I do plan on replacing the primer, just wanted to say that for now it starts and runs fine without the use of any prime. So even after I replace the primer I doubt I will need it.

It is a pull start so always a 2 handed operation anyway

great ideas... Many thanks..

I'm never sure whether to prime or not...

I need to have a try and see what works best..

Most carbureted engines have downdraft updraft carbs. Those where the primer discharges right above the carb (Continental C-series, for example) tend to get puddles of fuel in the carb throat at best, or the air box, when you operate the primer. Likewise, when you pump the throttle on a Marvel, the fuel goes down, not up into the intake runners. (When you pump the throttle the throttle plate opens and there's nothing to discourage the fuel from making its way down rather than up.

When I was just a budding student pilot, one of my instructors asked me what good it did to prime the engine. I told him, and then he asked "why don't you crank the starter while you're priming it?" "What if it starts before I'm done priming?" was my answer. His response was "so what?"

Since then I've never primed the engine unless I was cranking it over. No chance of an airbox fire, and always seems to work.

Downdraft or updraft?

Oops... Corrected!