1977 Johnson 70 HP - Engine Revs - Won't go

[johnjsa]

I am having a problem with my 1977 Johnson 70. It has power tilt but also an added CMC trim & tilt unit. It idles fine but when pushing the throttle, it seems to almost slip out of gear & engine rpm's go up. I had raised the motor on the CMC as high as it would go & was wondering if this was the culprit or if prop was the problem. Boat hasn't been out on the lake in a while.

 

[HighTrim]

Re: 1977 Johnson 70 HP - Engine Revs - Won't go

Sounds like the prop is slipping.

Draw a line across the hub and prop, run it until you hear it "rev", then re inspect. If the lines are no longer lined up, time for a prop rebuild or a new prop.