Overheating Problem

[Citylights]

Early this spring I bought a '76 Catalina27 w/ an A4 gas engine. The boat was already in the water and I did not have access to the previous owner therefore don't know the status of year-end winterization/spring launch activities (if any).
Upon first starting the engine, I noted what I thought was water flow out of the exhaust. Not being familiar with the engine (all my previous engines have been outboards) I do not have any sense of "normal" flow. Moreover, because the exhaust is very close to water level, there was spitting from the exhaust impacting the water.
After about 20 minutes of running the cabin filled with smoke and I shut down the engine. Upon returning to the marina I restarted the engine with no problem, motored in and shut it down. (After researching, I'm now pretty sure that the water was not flowing out the exhaust as it should.)
The boat is 2+ hours from my home so I can't check things quickly. Upon doing research on this site and others, I thought perhaps the water inlet had been closed (I since discovered it was open) and, thinking that, figured I had probably toasted the impeller. I ordered one from Moyer but when I went down to install it last weekend, I discovered the valve was open and the impeller is in good shape and turning. I started the engine, temperature rose fairly quickly and I did not see water coming out the exhaust. Upon turning off the engine I could hear water bubbling (as if boiling) somewhere.
Given the time of year, I've had trouble getting a mechanic to come by and take a look at it and I need to remove the boat from this marina shortly (and take it through the Delaware & Chesapeake Canal, so sans engine is not an option). I ordered and just received Moyer's manual, hoping that I might be able to solve this myself if I can't secure a mechanic. Based upon what I read in the manual, I'm guessing it is not a thermostat problem, but I'm hoping to find more help and advice.
I did note earlier in the week, a series of posts that discussed the possible need to prime the cooling system, but I did not see any reference to that in Moyer's manual.
Can anyone help? Any suggestions?

Thx,
Steve

[msmith10]

It could be a priming problem and that's easy to test and fix. There is a hose between your shutoff valve on the intake thru hull and the water pump. Disconnect this hose at the thru hull end (after closing the valve), hold the end of the hose up above the height of the water pump and fill the hose with water (from a bucket, funnel, etc). Now, hold your thumb over the end of the hose or clamp it off near the disconnected end and reattach it. Make sure the shutoff valve is open now, and restart the engine. This should prime the pump.
Assuming you have a wet exhaust (waterlift muffler) it is normal for water flow to exit the exhaust in "spurts", not as a steady flow, as the water is ejected from the water lift muffler by the pressure of the exhaust gases building up.

[msmith10]

If this doesn't result in cooling water flow, you'll need to check for an obstruction further down line. One common spot is where the coolant water exits the manifold and enters the exhaust pipe. You'll find a Y fitting at this point. Anyway, Don's manual has a thorough section on the cooling system operation.

[Citylights]

Thanks for the suggestion.....I'll give that a try this weekend and let you know.

best regards,
steve harris