2008 220, vibration in shaft help

[wakehead]

Hi all. 2008 220. On the water and I have this new vibration at really low speed and I assume high speed but I just don’t feel it as I’m going faster. Here is a video. This is not normal but can some one tell me what this could be. I can’t find any parts diagrams on the shaft. Could it be a bearing or bushing ?

[biacs]

Have you tried going to a different prop to see if you still have the vibration?

I have a standby prop that has a vibration at certain RPMs.


2006 SANTE - Bull in a China Shop - Central IL

[shag]

Most of the time this is related to a minor ding that you might not even be able to see. Like above stated, try another prop and see what happens. You should always have a spare anyway. Best of luck!

[wakehead]

I am sure it is not the prop. It’s perfect. Never tagged anything.

[shag]

Ok, have you checked the connection bolts on the shaft to the transmission/V-drive? And just FYI, there is a possibility you might not have even known you knicked the prop - it's happened to me before. These are Nibral props so they will bend first on purpose, to help prevent a driveline injury, Also check the cutlass bearing in the strut.

[bturner]

I can't open the file in 3 different browsers so I can really comment based on that but based on what would appear to be a non critical vibration statement these types of vibration issues then to fall in a couple categories.

• Prop - The advise given here is solid. If you have another or can borrow another to try whats the harm of truly eliminating that as a possibility. This would be my first "go to" as well.
• Alignment - Poor engine alignment will do the same and will wear the drive line as well. Probably one of the more common causes of strut bearing wear and depending on just how far out the alignment is it can reek havoc with the entire drive line.
• Strut - A bent strut bearing or worn strut bearing will dive a whole range of vibration issues. Here as with the prop it doesn't take a lot and can sneak up on you.
• Prop shaft - Doesn't take a lot of run out to set up vibration and once again wear a strut bearing.

Since your boat is older and you're 4 square against looking at the prop, take a look at the strut bearing. If you can see physical clearance, or the opening looks out of round you probably have a problem here. Grab the shaft and see if you can move it in any direction. You should have very little noticeable movement here. If you have movement here you'll need to replace the strut bearing which can take you down the "while you're in there" rabbit hole. As in "while you're in there" do the alignment, check prop shaft run out, replace stuffing box packing and such.

Moving along to alignment. If you're somewhat mechanically inclined you can check the alignment on an inboard fairly easily. Unbolt the coupler and and slide the 2 surfaces apart. Now move the coupler together until they touch then check the mating surfaces for gap. You should be somewhere about .003 for good alignment. If you haven't had your boat aligned in years (like most of us) this is probably going to be off and will need to be adjusted.

Based on all the above I think you can see why based on the above why people (like me) prefer to start with prop.

[wakehead]

Thankyou all for the responses. I am going to be having a look. I will tighten the bolts and turn it by hand to see if it’s crooked at all.