[alcodiesel]

Originally Posted by tenders

Chris, as I said on the Ericson site a few minutes ago, since you already know there is no thermostat installed, I think you should stuff a bolt into the bypass hose (the hose running from the tee into the thermostat housing), reattach the hose, and see how she runs.

It is entirely possible that you've got schmutz clogging the manifold, as is being helpfully suggested. But it's as, or more, likely that the problem is really just inconsistent water flow through the head due to the lack of a thermostat, and that's easier to fix with the bolt.

Once the bolt is in, if the problem persists, you can also deal with a lot of schmutz using the "acid flush" process. This is a good idea anyway with a new engine of unknown provenance, and I personally think the acid flush is somewhat easier than screwdriving junk out of the manifold. Plus, it will clean out not just the manifold but all the engine passages.

If the problems persist after the bolt and the acid flush, THEN get out the screwdriver. I'm 90% certain you won't need to.

Bonus point for use of provenance.