Hot Starting FI Engine
Joe,
You asked about hot starting the fuel injected engine, so here are my thoughts. And this is probably like picking a primer...there's a method for every pilot.
First of all, keep in mind that this applies only to my setup, which has the Airflow Performance FM-200 and a purge valve. This may not have a direct application for Bendix/Precision injection operators...although I think the concepts are generally the same.
Second of all, understand that I always shut down with the purge valve...but I also pull the mixture to cutoff right after pulling the purge valve. In some ways, I think I'm complicating things for myself by doing this. I think the *best* way to shut the engine down is to leave the mixture right where it is, usually pulled about halfway back, and just pull the purge valve. BUT...the self-conscious part of me forces me to pull the mixture as well. I'm just not comfortable seeing the mixture pushed in, even part-way, when the plane is sitting. Even though I *KNOW* it's fine with the purge valve pulled, there's something about seeing that mixture knob anywhere but all the way back that bugs me.
Ok, with that in mind, here's how I do hot starts... For me it depends on how long the hot engine has been sitting, and ambient temps to some degree as well.
***** 0 to 2 minutes *****
- purge valve in ("R" position)
- crank
- as it catches, mixture half forward
It usually catches almost immediately, as long as the plane hasn't been sitting for more than a couple of minutes.
***** 3 minutes or more *****
- purge valve in ("R" position)
- boost pump on for about 2-3 seconds -- this builds up pressure WITHOUT priming (note mixture is left pulled back all the way), and I believe this provides a little "back pressure" to aid in squirting a bit during the first few cranks
- crank
- as it catches, throttle open rapidly, mixture half forward, then close throttle as the RPM builds
***** VERY HOT start *****
- keep purge valve out ("ICO" position)
- throttle wide open
- mixture wide open
- boost pump on for about 20-30 seconds
- throttle closed
- mixture cutoff
- boost pump off
- crank til it catches, then same as above, throttle-mixture-throttle juggle
NOTE that the only time when I ever move the throttle or mixture before hot starting is when deliberately purging. Otherwise I don't touch 'em.
If I had Bendix/Precision injection (had it on a couple of "tightly cowled" Mooneys), I would do everything the same as above, just no purge valve and no purge option when VERY HOT. The key (imho) is not touching throttle or mixture, just cranking until it catches.
Electronic ignition sure earns much of its keep when starting a fuel injected engine, that's for sure.
Hope this helps,
)_( Dan
RV-7 N714D
http://www.rvproject.com