Yamaha VMAX 150 Idle Issues

[Atlanta Boater]

All,Have a 2 year old VMAX 150. Current problem: after running boat through out the day on the lake, it will not keep a steady idle and will shut off. Seems to happen after a long lake run of about 20 minutes or so, shut boat off, let it sit, then start, boat will no longer idle without shutting off.This has happened last two weekends; however, this past week, the dealer pulled the carbs and took some varnish off, still had problem yesterday.Did leave almost a 3/4 tank of gas in boat from last October or so, dealer had put fuel stabilizer in though, have been filing fresh gas on top of that.Dealer now wants to drain gas tank, thinks gas from last year causing problem. Wouldn't putting new gas on top of that mix it up?Engine runs strong when first launching with full tank, seems like middle of day problem occurs. Would a "hot" engine affect idle?thx

[Ray Neudecker]

The dealer is on the right path. Condensation in the tank can contribute to the problem. It certainly sounds like a fuel restiction problem. They can be difficult to troubleshoot. Running a small seperate tank with fresh gas will help to determine the direction to go now in curing the problem.