70hp engine running cool..poor idle..great wot

[roonie]

just got this used boat with a 70hp (1977) model # 70773/70779. The engine works great at WOT. I can place my hand on top the running engine and it seems cool. I can leave my hand atop the engine forever. I pulled the thermostat this morning and placed it in boiling water and the thermostat seems to be opening and closing fine.

The engine will not stay running at idle and coughs/spits then dies when trying to idle up and go. I have to restart the engine several times ..then...all of a sudden seems to work fine and goes. The engine seems to function great at high speeds and below ....its just when starting or trying to get to full speed. The engine will not work in trolling speed.

What should a fellow try next? Hotter plugs?

Ive heard these older evenrudes had issues like this that may be due to low idle speed jets that need to be drilled out. Does anyone have an info they can share on this? thanks

[highcountry]

I don't know anything about your motor, but it sounds like low speed jet setting or plugging and if not maybe timing. You might trya little sea foam in it and see if it clears up. As for the cool run, I would feel blessed.