Slipping???

[amkilla]

Hey guys need help again. My 2001 25hp (J25TVLSI) Johnson seems to be slipping or something when accelerating or sometime just when cruising. Ill be accelerating and all of a sudden the boat looses speed and it sounds like the engine revs. Sometime it will "catch" back and start running normal again. Sometimes it does it worse than others. My first motor so not exactly a expert but seem like maybe it could be the gears or something in the lower unit? When it "slips" it still gets some power to the prob but not much. Thanks for any help

 

[GA_Boater]

Re: Slipping???

Sounds like the prop hub is spun. Draw a line straight across the prop and see if it is still lined up after you run the boat on the water.

Do something like this -

http://

 

[amkilla]

Re: Slipping???

Thank you. I will try that next chance I get. Think it would still drive well some of the time and even at wot if it was a spun prop?

 

[ondarvr]

Re: Slipping???

Did it ever work correctly, or has it done this the entire time?

Could be a spun hub, but once they start spinning it just gets worse until you can't get on plane or even give it much throttle. Also sounds like it could be that the prop is ventilating when you apply power. Trim the motor up and down to see if you can decrease and increase problem. You may just need to lower the motor slightly on the transom. Check to see that the shaft length on the motor is correct for the transom too..

 

[amkilla]

Re: Slipping???

It didnt do it at first but Ive noticed it getting worse and worse since I got it about a month ago. When it first started it did it very little and sometime would go a long time without me noticing it but today it did it almost constantly although I did drive around all day and it would still plane out eventually with me just increasing speed slower or continuing to try and get it to. It doesnt have electric tilt/trim and its a long shaft but the guy before me had modified the transom so that the motor sits up higher.

 

[ondarvr]

Re: Slipping???

There is a flat plate above the prop, how far above the hull is the plate?

 

[amkilla]

Re: Slipping???

Roughly even. Which is where it is suppose to be, right?

 

[ondarvr]

Re: Slipping???

Yep, it's getting to sound more like a slipping prop hub.

 

[amkilla]

Re: Slipping???

Ok gonna try and check on that tomorrow. Thanks guys for the help. Will report back with findings

 

[amkilla]

Re: Slipping???

Ok finally got a chance to run the boat today and as told I drew a line straight across the inside of the prop and then drove it. Only drove it for a few min. but long enough so that I could feel it "slip" a few times. Then took the boat back out and the looked at the prop and it was still in line???? Whats my next step? thanks

 

[racerone]

Re: Slipping???

I would still borrow another prop or have a prop shop look at yours.

 

[rolmops]

Re: Slipping???

Prop slipping usually happens as you rev up the engine and at a certain rpm, not just out of the blue.
It may be that your prop drops out of gear and then slides back in,which would call for a remote control cable adjustment, or it may be that you have started to load your boat in a different way which causes the transom to be higher in the water. This can happen when their is more weight up front and less in the back. People sitting in the forward seats. This will drop the bow and raise the stern. It happens often on pontoon boats with forward seating.
Just for the hell of it,check if you have water in the bilge. If you do,it will greatly exaggerate weight shift ,because the water will run to the lowest point and add its own weight.

 

[amkilla]

Re: Slipping???

Ok im going to check on finding a prop shop. Its a john boat and I it has done it with only me in it which is the only way Ive ran it since I got it. Havent had anything other than me and a few fishing poles in it. Thanks guys

 

[amkilla]

Re: Slipping???

Ok havent been able to get a new prop or get to a prop shop but want to ask another question. Should I be able to spin the prop with my hand when it is in gear? When I put it in gear I can spin the prop with some resistance but I can spin it. The entire inside of the prop spins with it when I do this? Is this normal or does this indicate something else? Thanks

 

[Vintin]

Re: Slipping???

When you spin it by hand does the line you marked on it stay lined up?

 

[sndmntboy]

Re: Slipping???

Same thing happed to me last year with my 9.5 hp Johnson. Sometimes it would slip and sometimes not. I did it so much that the rubber piece in the hub had eaten away to nearly nothing and had eaten away at the metal inside the prop. The guy at the shop said he could replace it but couldnt gaurentee that it would stay. I had to get a new prop but after that no problems at all.

 

[boobie]

Re: Slipping???

Take it out and try it again. Believe it or not but the hub can slip and the marks will end up back in the same place. Have you got it marked in the right places ??

 

[amkilla]

Re: Slipping???

Yep stays lined up when i spin it by hand. Drove it for a good bit today. Did it some but not a lot. Usually after it did it if slowed down and then started speeding up slowly it would stop. No luck finding a prop shop around here. I feel pretty sure I have it marked correctly. Drew it straight across the inside across the nut. Ill try to get a pic but feel pretty sure I did it right. Any other possible issues that this could be? Or would it almost certainly be a spun hub and risk it just buying a prop ....its a little banged up so might not be a bad idea anyway.
Thanks

 

[boobie]

Re: Slipping???

Does it ever make a "clunk" when this happens ??

 

[amkilla]

Re: Slipping???

Nope. Nothing just looses thrust and revs up until I slow down.