All good info. So I let the motor sit while I was typing up my last post, I was letting it cool down (it was obviously beginning an overheat since with no water circulation…shut it down at 170°). The purpose was to run it out of gas since it would be a project to do later on.

I went to start it up about 10 minutes later while it was sitting in the test tank and woosh – out came a big glob of debris (probably from bugs or varmint) and it started pumping plenty of water. Operated at normal temperature.

So this has all been educational. I guess we’ll just leave the motor as-is – and I will say these little 5.5/6’s sure do run smooth and quiet when they have PSI >90. I’ve actually had a couple of 6’s as of recent that were all the way up to 110. Maybe my gauge is lying, but I didn’t think these old motors in this small range could even reach that high.

And without sparking the compression debate, they were all sitting for awhile and fairly dry in the cylinders (as in, probably sitting for 2-5 years outdoors exposed to the elements – these were short money pickups from various sources).

On a side note – this motor won’t stall out. I have always wondered why the choke knob on some of these early 60’s motors had the red triangle "caution" at the end of the knob rather than the more traditional round knob with silver outline. Up to this point, I haven’t had any of these small motors with such high compression. Was the choke the old way of shutting down a good condition motor? I had always thought it was just a matter of throttling all the way down to stall it out, not having to choke it off. But that was with motors that generally ran between 65-75PSI.