STBD engine has a breathing problem?

[Pha8]

2002 Carver 6.2mx Mercruisers

Twin 6.2 mx Mercs, stbd engine has a loud "hiss"?? Not sure if it has a air leak (Vaccume) or filter is dirty? Port engine sounds normal.

Any thoughts?

[km1125]

Are your spark arrestors clean? If not, remove them and clean them both.

I'd be checking hose connections too. Perhaps a vacuum hose has become dislodged.

I'd also look into the IAC valve and it's associated "filter".

[bud37]

QR_BBPOST 2002 Carver 6.2mx Mercruisers

Twin 6.2 mx Mercs, stbd engine has a loud "hiss"?? Not sure if it has a air leak (Vaccume) or filter is dirty? Port engine sounds normal.

Any thoughts?

Considering your other issues from the CO post may I suggest having a certified marine mechanic have a look at your boat and perhaps recommission it. This may give you an another experienced eye on things and perhaps notice something missed and save time hunting around.

A vacuum leak that loud would have the engine running poorly IMO.....could be the belt or one of the pulleys/idlers......check the inside of the belt for cracks in the ribs, if so scrap it and keep for a spare. By all means clean the flame arrestors anyway.

[krawdad]

I had this happen recently, the starboard motor developed a "very loud" hiss which could be heard on the bridge. Even with the hiss the motor ran normally. Changed out the IAC and hiss is gone. A month later the Port engine did the identical same thing. Changed that IAC and hiss is gone,