Problem with 90 hp Johnson motor

[squiggy53]

I had a problem with my 1998 90 hp Johnson outboard motor yesterday. We were running at about half throttle across the lake and all of a sudden it was like some on hit shifter into neturel and boat slowed down and motor reved up almost like we spun a prop or something! after checking prop appeared to be ok we continued on at speed just above forward. as we tried to advance throttle motor again reved and we were not able to go any faster than just a bit above idle speed. when we got home we hooked up the water muffs and ran motor thru all speeds forward and back and seemed fine. we out motor down into large garbage can full of water and ran thru all speeds and positions and all appeared fine!
Do you have any suggestions>

[Joe Reeves]

How did you check that propeller?

Your explanation indicates a spun hub on that propeller. Regardless of your propeller checking method, if it were me, I'd be putting on another propeller just to see what happens.

Other scenarios of which I feel sure you're aware of, that would result in that type problem......... Debris attached to hull throwing air pocket into propeller....... Engine tilted to an extreme....... Engine mounted too high on transom, etc.

[squiggy53]

if hub on prop was spun or stripped you wouldn't have any power at all correct> Runs fine at idle or just above idle but as soon as you apply anymore power it just revs . Can that be as simple as a prop problem?

[Joe Reeves]

if hub on prop was spun or stripped you wouldn't have any power at all correct> Runs fine at idle or just above idle but as soon as you apply anymore power it just revs . Can that be as simple as a prop problem?

In a word.... yes.

That description of the problem is typical of a spun hub.... grips somewhat in gear at a low rpm but slips completely when power is applied.

I asked how you checked that propeller... you didn't answer!

The proper method is to remove the prop nut and using a magic marker, mark a line on the hub that runs/aligns into the propeller. Now replace the prop nut etc and test run the rig so that you encounter the problem. Now, remove the prop nut again and inspect that line you made. If the line is now broken, the prop obviously slipped on the hub.