Idle issue on 2004 Yamaha F40?

[andymach23]

I had my 2004 F40 (15 hours run) idling at a steady 800 revs on the flush muffs in my yard a few weeks ago. The engine always starts without having to lift the fast idle lever.<br /><br />I went for a run yesterday and after cruising for 45 mins or so I brought the engine to a very slow speed. Just in gear with minimal throttle. The motor stalled and wouldn't restart without the fast idle lever being lifted.<br /><br />A while later I was idling in neutral and the motor's revs dropped to 600 after about 30 seconds or so and the motor stalled. I again had to lift the fast idle lever to get it to start.<br /><br />The only thing I have changed since it idled at a steady 800 revs in my yard was to add some fuel stabiliser. My fuel is also fresh. (The Quicksilver fuel stabiliser bottle was opened a few years ago if that makes any difference.)<br /><br />When I started the motor from cold before setting out on this trip, the idle was strong at a steady 800 revs.<br /><br />I had the motor serviced in February, and its still virtually new with 15 hours only so far. Apart from this it runs very well.<br /><br />Could this be an adjustment that is needed to the idle or could the fuel stabiliser be causing this?<br /><br />Thanks<br /><br />Andy

 

[rodbolt]

Re: Idle issue on 2004 Yamaha F40?

hello<br /> it sounds like you have introduced a contaminant to your fuel system. you may try draning the carbs and flushing the system with fresh fuel. the open stabil may have contained trash/water.