Hot Start

[Doug Linville]

I have PA-24 250. That's right carbureted. Supposed to be easy to start when hot. In the past this one was. I use the procedure described in the POH. It seems now that I need to prime in some manner. I have been using the throttle control rather than the primer. Usually achieves success but with what I consider additional cranking. Does anyone have a suggestion to help with a more straight forward procedure.

[JIMICS2452]

Use a little primer if necessary. Do not pump the throttle. All that does is to cause the accelerator pump to put gas into the carb throat, where it will run down into the air box. Any back fire at that point will cause a nice fire. Ask me how I found this out.

[Andrew Foster]

Doug,
We have a 61 250. Normally I start in two to four blades. The last time it got hard to start overhauling the mags eliminated the problem. We were at annual and very close to the 500 hr AD limit.
My technique is to engage the starter and then pump the throttle so any fuel is sucked into the carb and does not just fall down into the diverter shroud.
Hope this helps

Andrew

[Clarence Beintema]

The engine needs three things to run, fuel, air and sparks. I'd start with checking the spark plugs, electrode gaps and internal resistance. If these are good you'll want to find out how many hours on the magnetos since overhaul or last 500 hour inspection.

Battery strength, starter motor condition, starter power cable condition, engine ground cable condition all effect cranking speed and ability to spin the magnetos and produce good spark.

Clarence

[Trevor Gfeller]

For what it's worth I have the same issue with my 63 250 O-540. I've had good luck 2 shots of primer and a half inch or so in with throttle and full mixture. I tried the ICS POH recommendations to no avail.

My starter motor gets heat soaked making it rough turning through compression however

[William Hughes]

I fly a 250. When it is hot just cracking the throttle (no prime and no pumping) seems to do the trick just fine.

[William Hughes]

Also, double check your mag timing and your impulse coupler.

[LeWayne Garrison]

The 250's had either one or two impulse couplings. If yours is the A1A5 (I believe) it has only an impulse coupling on one mag. Make sure it is working properly. You should be able to hear it snap when manually rotating the prop. (That won't completely tell you it is functional, but if there is no snap, it is definitely not working). I have seen shops route the p-lead incorrectly and when you try to start it on the mag with the impulse coupling, you are actually starting on the mag without the coupling and trying to start the engine with the timing advanced. This will work when cold, but is very difficult with a hot engine. If maintenance on the ignition system was done recently, check this out. Some 250' s had shower of sparks and if yours is one of these, make sure that system is functional.