Merc 496 HO serging at idle
#1
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Joined: Aug 2018
Posts: 28
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From: Saugatuck, Michigan
Have a 03 Sonic 31 SS with twin Merc 496 HO's
the stb motor originally had a miss, rough idle.
found on the computer #8 injector was bad.
replace the injector, motor runs good.
Now I'm noticing the serging of the motor thru the air cleaner at idle ? Port motor does not sound like this at idle.
Any ideas what could be causing this ?
Almost sounds like its struggling for air.
Thank you
Bart
the stb motor originally had a miss, rough idle.
found on the computer #8 injector was bad.
replace the injector, motor runs good.
Now I'm noticing the serging of the motor thru the air cleaner at idle ? Port motor does not sound like this at idle.
Any ideas what could be causing this ?
Almost sounds like its struggling for air.
Thank you
Bart
#2
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Joined: Dec 2016
Posts: 583
Likes: 363
From: Portland OR
I'd try swapping the IAC idle air control valve over from the other engine to see if the surging goes away. There's also little sponge "mufflers" that are supposed to be by the throttle plate behind the air filter that can be missing over time. They help quiet the sucking sound. The are called IAC mufflers.





