Here's my first report on fuel pump and fuel temp. test:
I installed the original fuel pump. Has 6,000 miles on it. Aprox. 1/2 tank of fuel. Outside air temp. 58 degrees F. fuel temp. in fuel return bucket, 59.5 degrees F. (3W was sitting in garage)
I ran the engine at idle to make the engine overheat by running without any cooling air, creating skip fire from overheating.
After 5 minutes of running... no skip fire yet. The fuel pump outlet temp. was 74 degrees and the fuel in the bucket was 71.5 degrees.
After 20 minutes of running, the engine overheated and went into skip fire. The cylinder heads were aprox. 350 degrees. At this point, the fuel in the bucket was 86 degrees and the fuel pump outlet was 88 degrees.
The machined aluminum blocks that hold down the injectors and also act as the fuel rail/manifold were 99/100 degrees F.
The circulating fuel is COOLING the fuel rail/manifold, its' proximity to the hot engine was not increasing the fuel temp. to any significant degree. Any heating of the fuel appears to be mostly from cooling the pump motor.
When the raining stops, I'll take a hard run and record the results. Over time, and several rides, I'll see how the variables effect the fuel pump temperature.
