S&S Vibration

[josepcedwards]

When I took mine out Sat. to me at full throttle it had some vibration. Is this caused form it having a 351 in 2200 lbs boat? It may just be me. I just want to make sure this boat is right. Around 35 it was smooth. Any input would help! Thanks!

[thatsmrmastercraft]

Was the vibration you felt at full throttle in forward or in reverse? OK, seriously there are a lot of things that can cause a vibration. What is the condition of the prop? How about the engine? A slight miss can really show up under load. Engine alignment is another. How easy or hard is it to turn the prop while the boat is on the trailer? Those are probably the most likely sources.

[josepcedwards]

Originally Posted by thatsmrmastercraft

Was the vibration you felt at full throttle in forward or in reverse? OK, seriously there are a lot of things that can cause a vibration. What is the condition of the prop? How about the engine? A slight miss can really show up under load. Engine alignment is another. How easy or hard is it to turn the prop while the boat is on the trailer? Those are probably the most likely sources.

Prop-good, Engine-seems to run really good, Prop is kinda hard to turn. What causes that?

[cbryan70]

prop may be out of balance, shaft me out out of alignment or bent

[josepcedwards]

Originally Posted by cbryan70

prop may be out of balance, shaft me out out of alignment or bent

The owner before me did do some trans work. He changed the seals. Is this an easy fix? Something i could do?

[thatsmrmastercraft]

Originally Posted by josepcedwards

Prop-good, Engine-seems to run really good, Prop is kinda hard to turn. What causes that?

Prop should be kind of hard to turn without the transmission running. Of course you don't want to get anywhere near the prop with the engine running. With good engine alignment you should be able to turn the prop with one hand. Not an expert on this yet. I know the boat is new to you. What are the condition of the plugs, wires, dist cap & rotor, fuel filter. Is the timing set to specs? Is the advance working smoothly? Even old gas can cause an issue at WOT that you may not notice at part throttle speeds. And it doesn't take much of a bend on a prop blade to cause a vibration.

[cbryan70]

there are threads on here about alignment. Only way to tell if the shaft is bent is to pull it. Alignment there are measurments that I can not recall

[Willski]

I'm not sure what your used to, but my friend that had an 86 Nautique always thought my boat shook more than his and was louder. I thought the same, but of course my wake was 3x better! We checked alignment of the engine/drive shaft and it was all good. Just a bit more vibration than he was used to. No prop issue either. In my opinion, that era MC has a bit of a vibration at certain RPM ranges.

As far as prop turning hard on the trailer, that may depend more on how recently you have operated the boat and how tight the packing nut is.

If the vibration is excessive, I would first check prop condition, then alignment to engine, then it is possible the shaft could be bent, but don't fret just yet. It could be all normal.

[josepcedwards]

Originally Posted by thatsmrmastercraft

Prop should be kind of hard to turn without the transmission running. Of course you don't want to get anywhere near the prop with the engine running. With good engine alignment you should be able to turn the prop with one hand. Not an expert on this yet. I know the boat is new to you. What are the condition of the plugs, wires, dist cap & rotor, fuel filter. Is the timing set to specs? Is the advance working smoothly? Even old gas can cause an issue at WOT that you may not notice at part throttle speeds. And it doesn't take much of a bend on a prop blade to cause a vibration.

Im gonna do a tune up cause ill know I did it. Lets just say the prop doesn't turn as free as a wind mill, but can be turned with one hand. Im really new to these S&S and what i call a vibration may be nothing to someone that knows how they feel.

[josepcedwards]

Originally Posted by willski

I'm not sure what your used to, but my friend that had an 86 Nautique always thought my boat shook more than his and was louder. I thought the same, but of course my wake was 3x better! We checked alignment of the engine/drive shaft and it was all good. Just a bit more vibration than he was used to. No prop issue either. In my opinion, that era MC has a bit of a vibration at certain RPM ranges.

As far as prop turning hard on the trailer, that may depend more on how recently you have operated the boat and how tight the packing nut is.

If the vibration is excessive, I would first check prop condition, then alignment to engine, then it is possible the shaft could be bent, but don't fret just yet. It could be all normal.

Im used to a 05' X10. I really think that is my problem. I agree with it being in an RPM range from what i can tell too.

When i tried turning the prop... it was before i put it in water from it siting all winter.