John Hafen wrote:

What have you found to be the best hot start procedure for a TSIO 550, with mags, in an IVP?  I'm not talking immediately after engine shut down, but shut down on a hot tarmac after 30 to 40 minutes so the fuel lines are nice and hot and boiling the internal fuel.


Well, I'll open the discussion on this...and take any guff that results... :-)

I set the throttle to 3/8" in (just a bit more in than for a cold start), put the mixture to full rich, turn on the low boost pump and start cranking immediately. The engine will almost always start within two blades, but may falter and die. If it does, just keep cranking and give it a 2-second shot of high boost--and no more!--leaving the low boost still on. If it doesn't start within 10-15 seconds, turn off the boost pumps and stop cranking.  Let it sit with the throttle full open for a couple of minutes...don't rush it...and try the same procedure again.

When the engine starts, it will accelerate to 1200 RPM or so. Throttle back, but not to idle, as it will likely stall at idle until the lines/galleries are purged of air/vapor.

I've never had my engine fail to start using this procedure.

If you suspect the engine is flooded, you can confirm by checking for fuel being dumped out the cylinder drains/ sniffle valve. You have to get out of the aircraft to see this. Not possible to see the drain under the aircraft while in the cockpit.

Bob

PS: I took off from Williamsburg, VA last month after the airplane was refueled on the ramp and then heat soaked at 96 degrees for some time. The engine rolled back just after I was airborne, which I recovered by turning the boost pump on low. I've flown for three years now without using the boost pump at all below 15,000', so I concluded that I'd sprung a small air leak in the fuel system. A 100% check confirmed no leaks at all, so I now think the engine-driven pump may be getting a little weaker as it wears--and not clearing the vapors as well? In any case, I've added "low boost-ON" to my before-takeoff check if the temperature is above 80 or the airplane has been heat-soaked on the ramp.  FYI...