Slipping?

[christopher]

I have a 115hp mariner on a Nitro 185 sport fish and ski. My problem is that the motor seems to be slipping. From a stand still or from moderate speed if I go full throttle it starts out fine but then the motors rpm's will jump up and I get a lose of power(like if your clutch were slipping in you car). If I go back to neutral and try again it may take off fine or it may slip again.

 

[steelespike]

Re: Slipping?

Most likely you have a spun prop.If you mark<br />across hub and prop with waterproff marker.run it and see if marks line up.If mark changes a prop shop can replace the hub.

 

[christopher]

Re: Slipping?

Spike, I marked the prop as you said but this doesn't seem to be the problem. The motor slipped but the marks didn't chance. Any more suggestions?

 

[bigbluebirdy]

Re: Slipping?

Christopher,<br /><br />My guess would be that you're experiencing ventilation. Try this link... read about "ventilation". <br /><br /> http://www.boat-props.com/prop_basics.html <br /><br />Quite possibly your motor is mounted too high, or you're overtrimming it. Just a guess.<br /><br />bbb

 

[dutch135]

Re: Slipping?

Chris,<br />Has this problem just started? Has the boat been fine for a while then something changed? Or, did you just get the boat and are not sure if it has always done this? Also, when you marked the hub and prop, were you sure you marked across the center hub, the brass piece usually, and onto the propellor? Also, sometimes you can see under the nut holding the prop on where the prop and hub have spun and the thin washer might have signs of wear. Just a couple things to check out, to rule out the hub. I have just been thru the spun hub problem myself, and know the feeling of the slipping clutch feel. I also do get that in corners though with my good prop, but that is ventilation as bbb mentioned. Good luck!

 

[christopher]

Re: Slipping?

The problem started my last time out at the end of last year, no problems before that. Is this something that happens from hitting somthing?

 

[bigbluebirdy]

Re: Slipping?

Hitting something can definitely cause a spun prop. Better than tearing up your gearcase/lower unit. Do you recall hitting anything?<br /><br />bbb

 

[christopher]

Re: Slipping?

I may have tagged an old tree stump or three. One of the lakes I fish is full of stumps.

 

[ivar]

Re: Slipping?

Is there any signs on the prop from hitting? <br /><br />If if there's dings, gouges or a slightly bent blade the prop will be much more prone to ventilation than before.

 

[Dhadley]

Re: Slipping?

Chris - start with the basics. What prop do you have? Aluminum? What pitch?<br /><br />Im guessing you have an aluminum prop and it just may be getting worn. Hitting 3 stumps may have done the trick! Did you raise the motor or change the trim angle? It just sounds like ventilation, as stated.<br /><br />Good luck!

 

[Spidybot]

Re: Slipping?

Chris.<br /><br />Check this for all about props and more Wisdom of Propellers

 

[oldboat1]

Re: Slipping?

want to make sure you have a cupped prop (most are). But if you replace the prop, particularly with a used one, make sure it's cupped -- can take care of ventilation/cavitation issues.

 

[christopher]

Re: Slipping?

First I would like to say thank you to all that replied. Second is to say that all is cool now.<br />My problem was cavitation caused by a problem with my trim not letting me tilt the motor all the way down.