Hard to start when engine is hot

[Sonex1462]

Hi Mike, that is a great question.
I have been very fortunate with cool oil temps. I have determined that I have an error of around 10 degrees in my oil temp indications. My MGL Xtreme indicates 10 degrees cooler than the actual temps. I have never seen oil temps above 200 degrees (210 actual). Usually cruise oil temp is indicating 160 - 180 degrees. I will usually take off with oil temp indicating 90 - 100 degrees and then increase to around 190 indicated during the climb. That is with a climb speed of around 100 MPH.
CHTs have always been easy to control by adjusting power and climb speeds. I have not had a CHT go over 400 degrees in climb. Normally around 375-380 in climb. Cruise CHTs depend on how high a cruise RPM I use. When it is hot I usually keep my cruise around 3000 RPMs which has CHTs around 340 - 360. If I increase the RPMs to around 3200 - 3300 I will see CHTs around 375 - 380. So I usually cruse around 3000 RPMs when it is hot.
I have not flown my Sonex in the Months of June through September. It is too hot even early in the morning. When I do fly I don't like to start a flight if the temps are already above the low 80s and a I quit when It reaches 100. This is for my comfort. I think the plane would probably preform just fine if I monitor the engine temps and adjust accordingly.

[MichaelFarley56]

Those are impressive numbers John! I see similar numbers in my Waiex during the hot and humid summers here in Ohio. I'm glad to hear that the warm temperatures you experience down there don't have a really bad impact on the engine or the airplane performance.

Thank you for letting us know!

[mike.smith]

I'm pretty sure Don insulated the fuel line because it has what appears to be an insulator around the lines all the way to the aeroinjector.

Whether it's overkill or not, I have fire sleeve around all my lines, then I have the black insulation that you wrap around hot water pipes, and finally reflective heat tape (the fiberglass-based stuff made for engine compartments; not aluminum tape). It really did make all the difference in the world. I don't start my engine any different hot or cold. For a hot start it takes maybe 1 extra revolution of the prop to start.

[Titanium Cranium]

I took a little trip this past weekend and after only a 20-25 minute stop, I tried the hot start method of keeping the mixture at idle cut-off and then started slowly pushing it in as I started cranking the starter. It fired right up with no trouble at all. It's nice to know that I can do short re-fueling stops on trips without having to give my plane a ridiculous amount of cooling off time. I really appreciate all the help you guys have given me.

[MichaelFarley56]

Glad to hear it Tom! It sounds like you're flying the Waiex a bunch which is great!