Boat Noise while riding.

[LukePrinsloo]

The silicone I'm referring to is under the boat. It's applied around the intake grate to prevent cavitation. Several members who have sucked up ropes have lost some silicone around the intake grate. You can get under the boat to visually inspect it.

I know, the only silicone there is around the shaft where it goes into the hull.
google image here, let me know if you can see it. (my boat, just from google photos)

 

[Gym]

Sorry @LukePrinsloo, no pics showed up on your post. I'm suggesting you make a quick roll under your boat to inspect the caulking around the perimeter of each intake grate. Just run your finger around the perimeter. You should feel a smooth bead of calk with nothing loose or missing. Anything loose or missing WILL cause cavitation. The more that is missing the worse cavitation you will experrience.

 

[LukePrinsloo]

 

[Scottintexas]

Luke,
I'm not sure if this will fix your problem or not but here's my post about missing sealant and it appears you may have some missing also,

https://jetboaters.net/threads/cavitation-missing-sealant-in-pump-grate.884/

 

[Gym]

@LukePrinsloo. Ok, I now see your pics but they don't show the perimeter of the intake grate where it meets the gelcoat. That's the space that needs to be checked for calling. Pics generally won't show loose calling. That's why I'm suggesting you roll under there and trace around each grate with your finger.

 

[LukePrinsloo]

I've got some sealant so I'll do the above on friday, Someone is coming to look at the boat on saturday.
The thing is that in the linked thread it's mentioned that unless you cannot go over 45 mph you should have good sealant.
This boat is damn fast and does 48 mph easily with the whole family on board.
@Gym I apprecaite the help.
I had thought that it would be obvious if I did or did not have caulking.

 

[Gym]

No problem @LukePrinsloo. I was addressing your vibration issue which can be caused by cavitation but your correct I didn't catch your speed report on an earlier post.

 

[Scottintexas]

With my loose/missing sealant I could go 45+ I just had to nurse it through a certain range and then the cavitation sound/vibration would go away,

I might tell you liberally apply whatever household silicone you have all over the bottom side in any gaps to help troubleshoot it.

Does it make that vibration/sound when you run it on the hose ?

 

[LukePrinsloo]

With my loose/missing sealant I could go 45+ I just had to nurse it through a certain range and then the cavitation sound/vibration would go away,

I might tell you liberally apply whatever household silicone you have all over the bottom side in any gaps to help troubleshoot it.

Does it make that vibration/sound when you run it on the hose ?

It does not have the sound on the hose, though I've never rev'd it on a hose.

You might have finally solved the issue.
The sound is there in the early rpms, climbs as you approach 20 mph. At full speed it disappears/drastically falls.

 

[Gym]

It does not have the sound on the hose, though I've never rev'd it on a hose.

You might have finally solved the issue.
The sound is there in the early rpms, climbs as you approach 20 mph. At full speed it disappears/drastically falls.

You won't get the sound on the hose as you're bypassing the normal water flow you would get while in the water.

 

[Scottintexas]

to me running on the hose is just to help guide what direction to go next,

no noise on the hose -
more likely - air intrusion/loose sealant
less likely - bearing/shaft issue only under load in the water

noise on the hose -
has to be a bearing/shaft/impeller issue (since he already ran it without the shaft installed to exclude an engine issue)

 

[swatski]

Also check this and around. You may be sucking air into the pump in those places, along with what @Scottintexas and @Gym said.



Not a perfect solution, but if the pump vibration drives you nuts, one way to alleviate it is to switch to wear rings with plastic (delrin) inserts. Those work really well and quiet things down, but are of course are a lot more susceptible than SS insert OEM to being damaged/destroyed by gravel ingestion etc.

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