Very thick heavy weeds - Is that the problem ? or what ?

Water level has gone down on our lake and weeds are thicker than ever...

Problem: when I increase the the throttle the motor starts to idle high( scream) but the boat doesn't move forward at all.
I'll start slow and as I increase the throttle- the engine starts to rev and after a good minute or so the engine is idleing very fast (obviously I open up the throttle ) but she doesn't move. It appears the prop is spinning.

Diagnosis: I tried spinning the prop with the motor off but gear selector in gear or reverse & it seems to be stuck in gear .. not moving freely which I figure is a good sign.

Is this because of the heavy weeds or do I have a driveshaft issue ??

ohh - it a 1987 Johnson / Evinrude 30hp

Please advise,
M.

Re: Very thick heavy weeds - Is that the problem ? or what ?

Marianne, You could have a spun prop. Each prop has a piece of rubber connecting the brass hub the prop blades. If you hit something hard, the prop will slip. This usually destroys the rubber, and causes the prop blades to slip. Try the boat is clear water. If you have the same issue, it is likely a spun prop. You can also make match marks on the bradd hub and prop blades, and test the motor. If the marks no longer line up, that is the issue. Prop shops can repair....

Re: Very thick heavy weeds - Is that the problem ? or what ?

Marianne said:

Water level has gone down on our lake and weeds are thicker than ever...

Problem: when I increase the the throttle the motor starts to idle high( scream) but the boat doesn't move forward at all.
I'll start slow and as I increase the throttle- the engine starts to rev and after a good minute or so the engine is idleing very fast (obviously I open up the throttle ) but she doesn't move. It appears the prop is spinning.

Diagnosis: I tried spinning the prop with the motor off but gear selector in gear or reverse & it seems to be stuck in gear .. not moving freely which I figure is a good sign.

Is this because of the heavy weeds or do I have a driveshaft issue ??

ohh - it a 1987 Johnson / Evinrude 30hp

Please advise,


Marianne,
The rubber clutch on the standard props for this engine frequently become damaged whenever you
the prop is being impeded from turning while in operation. The problem is that on your motor, it
makes no finacial sense to repair it. I would perhaps suggest a 2 part prop. You only need to
replace the damaged portion, whether it be the hub or the prop.

Click to expand...

Re: Very thick heavy weeds - Is that the problem ? or what ?

Thanks gor your help ! This forum / site is invaluable to any boat owner... Great Job !

Re: Very thick heavy weeds - Is that the problem ? or what ?

I think we are being a bit drastic in our diagnosis. Heavy weeds can cause the prop to foul up with weeds causing "cavitation" and high engine RPM but no power being put to the water basically. Try running the boat in some open water that isn't clogged with weeds and see if you have the same problem. Run the motor in reverse whenever it gets fouled with weeds to clear it of debris. If it still does this in open water with no weeds, you could have a spun prop. Otherwise it's probably just fouled with weeds.

Jim311 said:

Re: Very thick heavy weeds - Is that the problem ? or what ?

I think we are being a bit drastic in our diagnosis. Heavy weeds can cause the prop to foul up with weeds causing "cavitation" and high engine RPM but no power being put to the water basically. Try running the boat in some open water that isn't clogged with weeds and see if you have the same problem. Run the motor in reverse whenever it gets fouled with weeds to clear it of debris. If it still does this in open water with no weeds, you could have a spun prop. Otherwise it's probably just fouled with weeds.

Click to expand...

I know it's an old thread but this likely happened to me today.
I Went boating to the Toronto island approx 15 miles from the ramp I launched. Navigated the channels within the island. Parked the boat for about an hour. When I hit the throttle after leaving the island, the boat wouldn't come up on plane. Around 3500 revs it stopped gaining speed and revs increased rapidly.

I thought oh checking the prop but I was alone and it was getting dark and choppy, so I headed back to the ramp slowly. From time to time I attempted to go on plane but nope, same behavior. I stopped at a marina contiguous to the ramp and lift the outdrive. Found a bunch of tick weeds all wrapped around the lower unit. Removed them and went to the ramp.

On the way to the ramp, I noticed the boat seemed to have more power. Pulled the boat out of the water. I thought the hub was shot but I couldn't.confrim; that prop does not have the conventional hub. It's an embedded type (Michigan wheel Rapture ss). So I replaced the prop with an aluminum spare I always carry.
Put the boat back in the water and problem disappeared.

I was convinced my SS prop's hub was gone. Now after reading this, it all makes sense. The weeds were messing up with me. Lol

17 footer bowrider. I/O Mercruiser 3.0 Drive alpha 1 gen1