Vibration in at low RPM's

[Kyletravis]

Howdy - this is a great forum, thanks in advance for your input..<br /><br />Have a 21ft Triton FS with a 2000 200 Optimax. Spinning a 19" pitch prop. The boat has a great hole shot, even with alot of folks on board, but during the hole shot, and while slowing down from plane, I get a vibration in the boat. I felt of the prop, and the edges are rough, to the point where it would scratch your hand if you ran it across the flat edge of the prop. <br /><br />Could this be causing the vibration? If not, any ideas on what it could be?

 

[Silvertip]

Re: Vibration in at low RPM's

Probably not! But a prop that is loose on the splines (installed improperly) or one with one or more bent blades will cause vibration. Hold a pointed object very close to the tips of the blades, but at the back side (away from the boat) and slowly rotate the prop. As each blade passes the pointed object, note the gap. If the gap varies significantly from blade to blade, the prop needs to be rebuilt or replaced.

 

[LubeDude]

Re: Vibration in at low RPM's

First off, welcome to the forums, there are several of us Bass Boaters here.<br /><br />I dont know why, but some three blade props vibrate some on the low side of the RPM range, I have had a couple. I doubt if the rough edges are your problem, but I would lightly smooth them off with a file. At the least, it will make your prop a bit mor efficient.

 

[imported_bjs]

Re: Vibration in at low RPM's

i have a small vibration in my boat but that only happens with one prop the other does not do that.i thought it was bent but was new.so itook it to prop shop and they said wasn't bent but they said that some props get a hold of the water better than others.so what ever thats worth i guess its ok only does this at low rpm's.

 

[b.gagnon]

Re: Vibration in at low RPM's

I had the same prob.. I took a file to the edge and it went away.

 

[walleyehed]

Re: Vibration in at low RPM's

I see 2 possibilities not listed yet...<br />On hole-shot, it's common to have a bit of ventilation occure, and it may be on 1 or maybe 2 blades causing a slight vibration.<br />When you decelerate, the boats motion through the water is faster than the prop wants to turn..it can slip on the dogs and vibrate or it may create a huge pocket of air behind the blades making it feel a bit funny.<br />The question I have is how does it hold mid-range throttle???? does the rpm remain consistant??

 

[Kyletravis]

Re: Vibration in at low RPM's

Originally posted by walleyehed:<br /> I see 2 possibilities not listed yet...<br />On hole-shot, it's common to have a bit of ventilation occure, and it may be on 1 or maybe 2 blades causing a slight vibration.<br />When you decelerate, the boats motion through the water is faster than the prop wants to turn..it can slip on the dogs and vibrate or it may create a huge pocket of air behind the blades making it feel a bit funny.<br />The question I have is how does it hold mid-range throttle???? does the rpm remain consistant??

 

[Kyletravis]

Re: Vibration in at low RPM's

I believe it did hold mid-range throttle and the RPM remained consistent, but I will be on the water this weekend and will pay close attention to that. BTW- the vibration is non existent once on plane, even at low speed, it seems to only come up when there is extra pressure on the prop - like you said when slowing down, or the same thing when in the hole shot...