JustinLCurrie posted a topic in Centurion Boat Maintenance, Performance, TroubleshootingHave a 2006 Centurion Avalanche C4 with a Mercruiser Scorpion 5.7 (aftermarket installed 5 years ago) just before we purchased it. Last year it started to misfire when under load - idle is fine. We have had the top end rebuilt and have replaced the boat computer (Motorola). With about $9K Canadian spend we still have a boat with intermittent issue and are pulling our hair out. It runs really rough - backfiring and won't deliver power when under load but if puttered around for 15-20 minutes with slowly adding revs it will then suddenly overcome the issue and will then perform flawlessly with no timing/backfiring issues. Love the boat for wake surfing but this issue is driving us nuts. Anyone else ever experienced something like this? Does not seem to be fuel related as when it does perform it is absolutely fine. Any advice or assistance would be greatly appreciated. With the amount we have spent at two repair facilities it seems like we should have a brand new motor set-up that works flawlessly vs. finding out our boat isn't working after being told it would.