how to fix propellor slipping

[goatboat]

hey guys. Just to say first im new to the forums and have boat a reken with evinrude 120tles engine. i use it mostly to go fishing with my dad but i want to use it to tow tubes and have some extra fun with it this summer. every time i try to go fast in it, i put the throttle down and when i get to to around 3000-3500 rpms somethings seems to slip, the rpm shoots to 6000 rpms, and the boat slows down. Ive talk to some people and they have told me it has to do with my propellor but they dont explain it enough that i can figure it out. everyone also says its easy to fix and do myself but im a little afriad of trying any tips or how to do it?
also if anyone has any other helpful tips about my engine 120tles 120 hp v4 2 stroke i would also greatly appreciate it

[Elton Smith]

The clutch dog may be slipping.Thats what kicks you into forward and reverse.Sometimes they get rounded off and when you put pressure on them they slip into nuetral.Might try adjusting the thro on the shift cable to go farther then it is right know.I,e, when you floor board it, it will bump and the motor will go wide open because it jumped into nuetral.

[wx2watch]

Although I am of the era when shear pins were used, is it not possible that the "rubber hub" inside the propellor is failing?

(While a clutch dog repair is not rocket science, it is intimidating for a novice, and so I would say "Not an easy repair on larger Hp motors".)

Let us know what you find,
John

[wx2watch]

Hmmm...., I just had another thought which is a much simpler explanation for your symptoms, although, we need to know if this happens ALL the time or just when you are tubing.

The propellor is "cavitating". See your local dealer (or a trusted friend) for an explanation and/or solution. A variety of factors are involved to effect a solution to this situation. Might be as simple as adding a "whale tail" to your lower unit if this is the problem.