2001 Mercury 300x ProMax

[78superboat]

Need help!Poor idle and excess fuel in intake plenum when motor tilted all the way up at the dock(not running).I cleaned out the vst,injector screens and fuel rail due to poor fuel from sitting,also checked reeds while I was in there.It ran better but still does not seem right at idle,plus excess fuel in plenum.It runs great off idle.Currently waiting on new plugs(ql77pp) to see if that helps.Also need more info on running the ngk br8hix plug.Thanks in advance!

[Eagle One]

Could be several things. First suspect would be the throttle position indicator (TPI) it could be telling the engine the throttle was open wider at idle. Timing could be an issue. To little idle advance would cause fuel to puddle. Could be a leaking injector?? even the computer could have a glitch.

[78superboat]

Eagle One, thanks for the reply.I just got the new plugs today but have not put them in yet.I also did a voltage test on the tps and it checked out ok(.94 vdc closed,4.6 vdc wide open).I think I need to get the guys at the local performance shop to hook up computer to check everything while it is running.The season is almost over and I will be able to go over everything.I will probably do a major tune-up over the winter,depending on results of diagnostics test.I will let you know what the results are.Thanks again!