1973 AQ170 with no water thru-flow

[gibbstobyj]

Last time i had it running was about 4 weeks ago on muffs in the driveway and water was flowing through and out the exhaust. Today I fired it up again in the driveway in prep for an evening ride this week. Good thing I did because now I do not get water flowing through. I checked the impeller and it looks good and spun when i turned it over.

Once it cools I'm going to pull the thermostat and probably just replace it.

My question: Is there any other reason that I would not be getting water flowing throughout the entire cooling system? Any other place besides impeller and thermostat that would be holding back the water?

 

[gibbstobyj]

From reviewing other posts I was reminded that the last time I ran it I had water running out the back once I turned it off. So now I'm wondering if my intake line that connects to the outdrive is bad. I'll be checking that also...

Still open to other ideas or just a confirmation that I'm looking in the right areas...

 

[gibbstobyj]

Ok. Took out the t-stat and threw it in the oven set to 170 (that's the lowest i can set our oven) and it opened as expected. So I have reasonable confidence that it is opening correctly in the 150's-160's range. I checked my rubber intake tube and, while it's started to rot where it connects to the outdrive, i didn't see any hints of leaks out. How would you test it for suction in? Regardless, I'm going to order one to replace it just for peace of mind.

While i had the t-stat area opened, i poured water into the water lines and then reassembled. Wouldn't you know, it ran water through the system and out the exhaust the entire time (10-15 minutes).

HOWEVER, my temp gauge still ran up to 190-200 and stayed there while it ran. I only ran it between 1200 (idle) and about 2200 rpms. The water coming out was steaming hot and my cylinder head was hot, but my exhaust manifold was only warm to the touch (I could leave my hand on it with no concerns) .

So, what should I make of all this? Everything i'm reading says my temp should be in the 160's. Seems like i need more water flow. Either more volume or faster flow? Could an air suction leak be the cause of this? I would appreciate any thoughts.