25HP tiller problem

[54Hornet]

Hello,
My 2000 F25MLHY tiller engine is acting up. I was hoping someone here could suggest a solution.
First off I will letyou all know I am pretty clueless as far as engine repair,so I will try to describe what's going on.
Three things were happening, one after the other and NOT at the same time.

I started fine and was putt-ing along in a no wake zone. When I cleared the no wake zone and went to slowly give it more gas there was a slight delay,then a excessively rapid acceleration. I let off the gas (tiller) and tried it a few more times with the same result. Then when I throttled up it started reving very high as if it was out of gear in neutral,, until I throttled down. Throttled up and down a few times with that same result.
I was on a tidal river that was flowing pretty strong so I thought it best to return to the ramp (twenty minutes up river on a good engine!) I turned the boat around and gave it the gas, motor quit. Re-started after a few pulls. But now if I throttle up barely over an idle it quits. The throttle felt funny too. It felt like it was in neutral.
I am now barely making headway trying to get back up the river. After a half hour I was about to give up when it for no reason (divine intervention) gave me more speed. Now I'm making reasonable headway I wasn't going to move anything. When I was by the dock I goosed it and it seemed to be normal again!

Sorry to be so winded but does anyone have a clue what's going on here?
Thanks
Mike

[robert graham]

Sounds like you may have 2 problems: a spun prop, where the black rubber bushing inside the prop has failed and when power is applied, it slips some(like a warn clutch in a car), and water or debris in your carburetor, partially plugging those tiny fuel jets. You may need a new prop and a carb cleaning.
Good Luck!;

[54Hornet]

Thanks Robert,
I read somewhere to check the prop,, disconnect spark plugs,,, put it in gear and stand on the prop? Will wait for a reply before trying that!

What I found strange was when it started running right, it was running like nothing happened at all no slipping or revving.
And as mentioned when it is acting up, the tiller handle/throttle feels weird it feels like it does when the engine is in neutral,,with a small range of motion,, even tho it is in gear.

[TownsendsFJR1300]

+1 on the above..

If the prop bushing is worn out, just put it in gear (engine OFF, spark plugs in-you want resistance) and then try turning it by hand. I suspect it'll turn/slip pretty easy being how you described it...

As for the the other problems, check your linkages, it sounds like their rusted up.

The carb does sound like it clogging up. Drain the float bowl(s) into a small, clean container (I like used tuna fish cans) and check for debris/water droplets. Flush by squezzing the primer bulb. If the engine is still semi running, you may get by running some Seafoam or Yamaha Ringfree to clean the carb.

If it doesn't help, either a carb dip or pull the float bowl to clean the main and idle jets (the idle jet is particularly small)