Rumble at idle speed.

[Terrance]

Hey all Glastron Gt187 jet boaters. Just checking out if you all experience a rumble at idle speed, that goes away under minimal power and higher power?

 

[McMark]

Don’t have a Glastron but the Yamahas do that also.

 

[BobbyP]

I haven’t experienced that...

 

[Floyd]

I haven't heard that. Does the rumble sound louder with the engine hatch open, or is it resonating forward in the hull?

 

[Terrance]

I haven't heard that. Does the rumble sound louder with the engine hatch open, or is it resonating forward in the hull?

Sounds like it is coming forward from the rear. It's like a rumble from a low idle motorcycle.

 

[Terrance]

Don’t have a Glastron but the Yamahas do that also.

Thanks for your reply. Our Seadoo Spark does it at idle also. Just curious.

 

[Cobra Jet Steering LLC]

The amount of water in the muffler , more water makes it quieter less makes it louder. An obstruction in the water line can do it even a slight obstruction

 

[Terrance]

thanks for the reply...that seems sensible!

 

[Cobra Jet Steering LLC]

Also if you run your engine on the trailer without water going to it, you reduce the water level in the muffler so you should notice the engines are louder when you first put the boat in the water and after a few minutes the noise level should quiet down somewhat . I also believe that the water level drops at planning speed so this also contributes to the louder engines people dislike. Sea doo had variable valves that changes the level of water in the mufflers at speed It has been years since I owned one so I forget the name they gave it but it looked like the top of a rave valve as it operated off engine vacuum back by the muffler and I believe it was adjustable also.

 

[Terrance]

The amount of water in the muffler , more water makes it quieter less makes it louder. An obstruction in the water line can do it even a slight obstruction

Thanks for your reply...wondering how to clean the muffler water line?
Thanks,

 

[BobbyP]

Make sure the black strap on your exhaust resonator is still on...

 

[Terrance]

Make sure the black strap on your exhaust resonator is still on...

Will do. Is that a strap around the water box ?

 

[BobbyP]

Yes. It’s big, black and plastic.

 

[Terrance]

Yes. It’s big, black and plastic.

Well what do you know. The black 20 inch rubber strap was split and it is not attached. Do you know what the strap attaches to? I am trying to find the part number for the rubber strap or a good replacement???

 

[BobbyP]

Well what do you know. The black 20 inch rubber strap was split and it is not attached. Do you know what the strap attaches to? I am trying to find the part number for the rubber strap or a good replacement???

It attaches to brackets on both sides of the resonator...The part number is on the strap.

 

[BobbyP]

https://www.google.com/search?q=brp...6BAgLECg&biw=414&bih=622#imgrc=PO4RpDfBDXMW-M:

 

[Terrance]

Hey Bobby... Thanks for the reference. I purchased the same strap from the Seadoo shop locally today. I appreciate your replies and help. Cheers!

 

[BobbyP]

Hey Bobby... Thanks for the reference. I purchased the same strap from the Seadoo shop locally today. I appreciate your replies and help. Cheers!

No problem! If you picked up a new strap, it might be hard to get it on, I stretched mine out for 24 hours and it made it easier.

 

[Terrance]

Hey Bobby. Got the rubber band on the hooks. You were right. A tough fit for sure. The good news is it did quite down the rumble back to where I remember it to from new. Thanks again.

 

[NavyShooter]

Got a picture of where this is on the engine? I'm curious now....something for me to look at over the winter.

I brought my boat in today. :-(