Engine noise and power surges

[FunonH2O]

Just recently upgraded from a 150 215hp Speedster to a 2012, 180 Challenger 260hp. With kids and grandkids the extra room of the Challenger was really needed. We love the boat as we do a lot of tubing and skiing and now several riders can come in the boat. I have a couple of issues I wonder if anyone has come across. Engine noise seems is louder than I expected. The engine cover has sound attenuating foam glued to it. But both the left and right side covers do not. Has anyone out there tried gluing some sound attenuating foam under those 2 covers, and did it cut down on engine noise?
The engine surges at mid range power settings. It’s fine at idle and higher power settings, but between 20 and 25 mph it surges. Any thoughts out there on this issue. Thanks

 

[MacSeaDoo]

Can't help you on the noise...

As for the surging, I had this problem with my Speedster 150 and it was a leaking intercooler.

 

[FunonH2O]

Oh, I forgot to mention, just put in a new intercooler. I bought it, not knowing the intercooler was leaking. Got it in the lake and could not get it on a plane. Intercooler was pouring water into the intake.
new intercooler installed by reputable Sea-Doo dealer. It tops out about 55, with no surge. It’s only at the middle RPM, so I hope it’s NOT a bad intercooler
Thanks for bringing it up though.

 

[RTTX]

I’m not familiar with the Challenger’s left and right side covers but I do have a Sportster with the OEM sound deadening foam on the underside of it’s engine cover.

I found this for stuff for my Sportster - using it in engine compartment (and also behind four 6.5” speakers and one 12”sub) for extra sound dampening.

it’s intended primarily automotive firewalls but checks all the boxes for marine use (heat, oil, fuel and water resistance) and is virtually an except match for the Sea Doo factory foam.

https://www.amazon.com/gp/product/B07782F7S6/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&psc=1

 

[FunonH2O]

Thanks, I will get some and try it under the two hatch covers and see if it helps.

 

[trevorc5505]

I put a bunch in my challenger recently and it made it a TON more quiet. I did the side hatches like you're talking about as well as the seat storage boxes on the left and right rear.

 

[FunonH2O]

Thanks for your reply. Am still waiting for my order to come, and will do the same as you did.

 

[xspook]

Can't hurt to change the plugs when you experience engine surging.

 

[FunonH2O]

Thanks and your probably correct, except that I just put in new ones. These have about 5 hours on them and it’s been doing this since I put them in.

 

[trevorc5505]

Thanks and your probably correct, except that I just put in new ones. These have about 5 hours on them and it’s been doing this since I put them in.

Was the problem happening before the spark plug change too?

 

[FunonH2O]

Yes, and I discovered the leaking intercooler. So, replaced the intercooler, changed oil and filter, new plugs and same issue. Idle ok, barely above idle to 3000rpm, engine surges. From about 3200 rpm until top rpm, it’s smooth.