1984 johnson 35hp...spun prop or bad LU?

[Kajun37]

today i took my 18ft jon boat out in the bay for the first time and wanted to just ride around and burn a 6gl tank of gas close to shore..i burned about 3/4 of a tank a of gas going up and down the shore....then the motor started just rev'ing high and not pushing the boat..i managed to limp back in on what i think was prop exhaust lol the prop looks like its turning but it ain't throwing any propulsion......i guess its either a spun prop or a bad lower unit...my question is what are some troubleshooting tests for spun prop or bad LU?

when i got home i flushed the motor and it goes into forward and reverse just fine..no noises or anything..pretty smooth ....compression test was good.

 

[freddyray21]

Re: 1984 johnson 35hp...spun prop or bad LU?

mark the prop with the line across the prop and the hub and run it. If the hub is spun the lines won't match up after running it. Or get another prop and try it. More than likely a spun hub. The major problem with slipping in that lower unit will be the clutch dog which will slam in and out of gear and make the motor buck.