79 Johnson 115TL79R - Best Way to Flush Cooling System?

[dumb boater]

Due to over heat and other issues, I took the lower unit off and replaced the water pump. I'm also replacing the head gaskets and a few other things. This is an old boat and the impeller from before basically was in pieces. I noticed some of the old impeller in pieces at the water intake. I cleaned all that out. Now I wonder how much is in the various parts of the engine.

Now, if I attach a hose to blow it out, what do I need to remove on the engine to ensure all the junk gets blown out? Right now the telltale elbow is off plus the tubes to the heads. Will that work? Or do I need to do more?

Can I do this with the heads off or should I wait?

Or what exactly should I do?

 

[gsyfishy]

Re: 79 Johnson 115TL79R - Best Way to Flush Cooling System?

You could have blown water down from the t-stat ports when you had the lower unit off, but you can still get it all out when you have the heads off. You will need to clean the cooling ports anyway, the only issue will be, is if there are any pieces from the heads to the lower unit in the pick up tube.