I've been under the impression that risers and manifolds , when it came to service, where like warranties, 400 hours or 5 years, whichever comes first. So I'm in the market for a new used boat and Broker says one owner, meticulous care and records on this Formula 31 with 2005 twin 6.2 FWC engines, with 375 hrs. But, when I asked about the risers and manifolds he said the boat is regularly serviced and they have been checked routinely and they are not in need of replacement. Another one , also 2005 , but a 34 with twin 496 Horizons with 2oo hours just had manifolds and risers changed ($11K). So what do I believe? I can't afford to buy the boat and change these right away.

Alot depends on salt or fresh water.

Padraig

Sorry, I should have mentioned all salt water boats

I replaced risers and manifolds on my 2004 baja in 2012. Should of done it sooner, almost ruined my engine. Risers actually had holes in them. Boat used in salt water. Manifolds not as bad as risers. To answer your question, you will be needing risers and manifolds soon in my opinion.

Thats kind of what I was thinking too, thanks

Depends on manifolds and risers. And for 11gs I hope that was headers. That's outrageous