I just changed my risers, manifolds and spark plugs everything from the elbows down seemed fine. After starting the boat and taking it for a test drive I notice at very slow speeds near idle a knocking/studder noise coming from the engine. I didn’t have this problem prior to changing everything listed above. Could this be a linkage issue? I had to remove a bracket containing two linkage cables and buy them back exactly how I remembered they were but something is off now. Any ideas? Appreciate the help in advance.
Mercruiser 5.0 Mpi low idle knocking
- Thread starter Danny t
- Start date
scoflaw
Well-Known Member
- Aug 10, 2011
- 6,395
- Boat Info
- 1999 Powerquest legend 260 sx 502 mag
2005 Baja 242 islander 496
- Engines
- 502 mpi Bravo 1
496 mag B1
linkage won't make noises, maybe an exhaust gasket. If it does it at idle get your head in there.
BillK2632
Well-Known Member
Sounds like the exhaust flappers - they sit in the exhaust at the top of the Y pipe where the riser connects. Could have gotten disturbed while replacing the risers.
