prop problem? gear problem?
 

today was the first day she was out. this year upgrades included a new (recon) lower unit, rebuilt carburetor and a 21 pitch prop a buddy let me use. i always used a 19 prop. wanted to try a 21 pitch to see how different it was. once all the vitals of the boat checked out, oil pressure and temp, it was time to open her up, so getting up on plane with a 21 is different then a 19. the first time i almost got up on plane, my engine revved jumped and i stopped moving... felt like the prop fell off...trimmed the outdrive up and prop is still there, tried it again, same thing happened, tried it a 3rd time, this time with someone watching the best the could making sure the prop wasn't coming out of water, it didn't appear so, but obviously tuff to tell. boat still drove fine at 10mph, went in forward and reverse no issues.
so, could the prop bearing spun out could the outdrive gears grinded? i checked the oil and the two screw tips, the lower unit was fine, the upper unit screw did have a few shavings on the tip, very fine almost look like graphite out of a tube.

ive never spun a prop or has this issue in the 5 years ive owned this boat. gonna put the 19 pitch prop back on and give it another go . any other advice?

Re: prop problem? gear problem?
 

There is a rubber piece in the prop hub that could be dried out and need replacing. It will cause what you are seeing. I had mine go out once and you could put it in gear and it would go but you couldn't give it any gas as this part is there so if you hit something this piece is sacrificed to prevent outdrive damage.

Forgot the name but prop shops can check it for you.

Re: prop problem? gear problem?
 

We had a trip at Lake Powell ruined by a prop that spun out. You could get almost get to plan and then RPM's would jump and the boat would decelerate. We pulled up to shore, shut off, put the boat in gear and tried to spin the prop. That didn't work. The prop was brand new, we had JUST put it on. We thought we had lost our lower end. Turns out we should have just put the old prop back on (we had it in the back of the boat the whole time).... Turned out house boat in 3 days early....

Sounds similar, I'd swap that sucker out with the 19 and see if you are still having issues....

Re: prop problem? gear problem?
 

This the most likely culprit.. these hubs eventually wear out. The hub kits run around 40-60 dollars i believe. We had to re-hub one of our props last year.