Re: ’67 80 hp V4; checking for air leaks?

[RICK EICHRODT]

From what I have read, you took a motor off of one boat (short shaft) and installed it on another boat (long shaft). Then you took the boat out and it would not run at high speed, bogged down. Have you ever considered what prop you are running, the load of the boat (weight) and other factors as such as something disrupting the water flow to the lower unit like a keel or depth finder pod directly inline with the lower unit? Secondly, you claimed to have cleaned the carb several times. Did you fully dissemble the carb, taking the high speed jets out, dismateling the venturi nozzles and replace o rings directly under the venturi clusters? How did you line up the clusters as there are special tools to locate them directly in the center of the venturi’s? Lastly, a leaking block or air leak would only cause a lean condition, coughing at idle. Usually a bad crankcase seal will have oil coming down the sides of the block. Very seldom will you have a faulty crankcase sealing issue unless someone has taken the block apart and not put it back together with the right sealer. Never rev up the motor in neutral or you can have the "run away" issue as there is no load on the motor or drag to slow the motor down. Those old gearcases had a special prop with a smaller hub that the gearcase to improve performance. You might check to see what prop you are running as I am sure the prop from your short shaft boat will not work with a heavier long shaft one.