Volvo Penta SX with bent shaft

[Michigan Jason]

Ok, I was out on the boat (wich has been running great) and had my uncle out to inspect it. He is a 40 year marine mechanic BTW. The second he told me (while in neutral and bocked) to bring her up to 1500 RPMS he said WTF is that vibrating. He was extremely concerned about it, we took it out for a ride and this is when I told him that when I look at the shaft the prop is connected to I can see that it is not perfectly straight. I can see a slight bend in it. He flipped out and told me to get the boat out of the water immediatley. So I did, now he has my outdrive and is looking for a used shaft. How much is this part going to cost me? (he also checked to see if I had water in my outdrive, and I didn't)

Thanks guys.

 

[rodbolt]

Re: Volvo Penta SX with bent shaft

find a real mokanik.
bent prop shaft simply WILL NOT cause a vibration in nuetral.
ONLY way to test a propshaft,unless its seriously bent, is with a dial indicator.

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

find a real mokanik.
bent prop shaft simply WILL NOT cause a vibration in nuetral.
ONLY way to test a propshaft,unless its seriously bent, is with a dial indicator.

I should not have said it like that.. I should have said, that he noticed the vibration in the boat while at 1500RPMS in neutral. Then while driving i told him about the visible runout, and as he said volvo penta should have 0 runout. At first I think he was thinking it was the gimble bearing while in neutral.

 

[Don S]

Re: Volvo Penta SX with bent shaft

that he noticed the vibration in the boat while at 1500RPMS in neutral.

In neutral, the prop doesn't even spin, how could it cause a vibration just sitting there ?????????
If it's just a slight vibration, at only 1500 rpm and goes away at 1600 or 1700 rpm, I would be inclined to think it's just the natural harmonics of that engine, in that boat.
Does the vibration change if trimmed up or down at 1500 rpm?
How about if you turn left and right?

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

In neutral, the prop doesn't even spin, how could it cause a vibration just sitting there ?????????
If it's just a slight vibration, at only 1500 rpm and goes away at 1600 or 1700 rpm, I would be inclined to think it's just the natural harmonics of that engine, in that boat.
Does the vibration change if trimmed up or down at 1500 rpm?
How about if you turn left and right?

I do not know about the left and right or trimmed up and down. My outdrive is no longer on the boat. It is going to a volvo specialist. Like I said though, the runout was the most severe my uncle has seen in 40 years.

 

[Don S]

Re: Volvo Penta SX with bent shaft

Like I said though, the runout was the most severe my uncle has seen in 40 years.

Ok, so it's bent. But that is not what caused your vibration. If it vibrates in neutral that shaft won't be turning, so how can it be the cause of the vibration ?????????

 

[mcleaves]

Re: Volvo Penta SX with bent shaft

Ok, so it's bent. But that is not what caused your vibration. If it vibrates in neutral that shaft won't be turning, so how can it be the cause of the vibration ?????????

Yup, you have two problems going on here. Answer Don's question

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

Lol, I understand that unless that shaft is spinning that I wont have vibration in lue of the shaft spinning.

Now, as to my original question, what am I looking at for cost of a used shaft or a new shaft? Any clues?

The vibration in neutral I had only really noticed while I rev it in neutral and I just thought it was becuase I was reving it up on neutral. I am not sure what would cause my boat to vibrate while in neutral and at 1500 rpm. Any clues?

 

[burp]

Re: Volvo Penta SX with bent shaft

In 2000, a prop shaft for my 1998 Volvo SX outdrive ran $450 plus labor to replace......bent by a stick that passed between the aft edge of the skeg and the SS prop. Skeg had a 2" section pushed to the side, prop was unharmed. Prop shaft was bent 3/16".

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

In 2000, a prop shaft for my 1998 Volvo SX outdrive ran $450 plus labor to replace......bent by a stick that passed between the aft edge of the skeg and the SS prop. Skeg had a 2" section pushed to the side, prop was unharmed. Prop shaft was bent 3/16".

Mine is bent like this as well. I hope I can get one at that price. Was that new?

 

[Sparkinator]

Re: Volvo Penta SX with bent shaft

If it is not bent too badly, there are shops that can straighten them.

Mine wasn't bent too badly and I got it straightened for 225.00

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

If it is not bent too badly, there are shops that can straighten them.

Mine wasn't bent too badly and I got it straightened for 225.00

doesnt it weaken it though?

 

[Sparkinator]

Re: Volvo Penta SX with bent shaft

I'm sure it weakens it some. I'd be leary of bending and straightening it numerous times, but the strength of the shaft after straightening it once wouldn't be a real concern to me. Making sure they got it straight and not hitting something with it again would be priorities though.

LINK

These guys seem to have it figured out.

 

[Borchik]

Re: Volvo Penta SX with bent shaft

We straighten them all the time without even taking the drive apart. SX drives are very strong internally, a little patients and a bottle jack with all fix most bent shafts. As everyone else said though the vibration in neutral wont be caused by that...gimbal, ujoints or something along those lines.

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

We straighten them all the time without even taking the drive apart. SX drives are very strong internally, a little patients and a bottle jack with all fix most bent shafts. As everyone else said though the vibration in neutral wont be caused by that...gimbal, ujoints or something along those lines.

The U joints looked and moved great, the gimbal is where I think I am getting that vibration from. Is it a big concern?

 

[Borchik]

Re: Volvo Penta SX with bent shaft

yes, you should have it changed. its a quick job for a dealer, especially if you have the drive off already.

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

Is there a cost estimate for the part?

 

[Borchik]

Re: Volvo Penta SX with bent shaft

the cost is about $80 for the bearing i believe. as long as the bearing comes right out and a new one goes it easily it usually takes about 15 minutes. however sometimes that can be stubborn and it could take quite a bit longer.

 

[Michigan Jason]

Re: Volvo Penta SX with bent shaft

I see, I should get an answer from my uncle today as to the cost that I am looking at, I am hoping I dont have to B.O.A.T!

 

[Don S]

Re: Volvo Penta SX with bent shaft

as long as the bearing comes right out and a new one goes it easily it usually takes about 15 minutes.

That does NOT include pulling the outdrive or putting the drive back on, or the time it takes to get the parts, and gather up the tools necessary to do the job. Everyone forgets that's part of the job you have to pay for when you take it to a shop.