Question I HAVE TWIN 8.1 VOVLO GI V-DRIVES IN A CHAPARAL SIGNATURE 350. PORT ENGINE WILL NOT REV PAST 3300 RPMS. I SWITCHED ECM FROM OTHER ENGINE, STILL NOT RUNNING RIGHT. IT SOUNDS LIKE ITS SUCKS AIR ONLY WHEN YOU TRY TO GO ABOVE 3300 RPMS. ENGINE WILL REV UP TO 5000 IN NEUTRAL WITH NO LOAD.
Answer a couple questions, is it fuel injected ..?? has it been sitting for any time??? have you checked fuel pressure??? you switched ecm's so lets look at fuel ....if you can, dissconnect the tach and see what happens, sometimes the tack can afect the ign..but you need to figure out is it fuel, or ign. failure
you can get back to me at docksidemarine12@aol.com good luck..