Overheating on the highway. 76, 2.0 Options

[SVG223]

My 914 overheats on the highway. I had concerns about the air flap, but I think the thermostat has broken and it stays in the open position. I thought something might be clogging the fan but it looks clear. I wonder about the heater air hose that goes over the motor. It could be blocking some air possibly. I may try to tie it out of the way. After exiting the highway and stopping at a stopsign the idle was extremely low, I was surprised it was still running. I turned the engine off for a while and it ran better after it cooled down. Any ideas would be appreciated.

[SVG223]

I think the ignition timing has been retarded by a bunch. I just turned the distributor counter-clockwise enough to increase the idle by 1000rpm and it ran better, so far no overheating but it's not summer yet. I need to get a timing light. I tried to get it to ping but it didn't so I need the light. It is running well so far.

[Superhawk996]

tried to get it to ping but it didn't so I need the light.

You are playing with fire.

Detonation kills engines so fast you would hardly believe it. The ability to hear detonation on an an air cooled engine is impaired by the valve clatter and fan noise.

Get a timing light on it. Stop guessing