Any input on this mystery is appreciated. I've got a 2004 Yamaha 90 4 stroke purchased last year with 24 hours on it.
We've put about 60 hours on it this season and I've noticed the idle getting progressively lumpy over the summer. In neutral at the dock it stumbles a little like it's missing slightly. Warm, it idles at about 600 rpm but has me reaching for the throttle as it sounds like it's going to stall. Despite this it has run fine at all speeds above idle.
Last week, the day after a particularly long cruise (for me) of 50 miles, it started with a fairly large cloud of blue smoke and idled very rough as well as ran rough in gear at dead slow. Blue smoke out of a low hour engine that's not supposed to burn oil has me twitchy to say the least...
Any ideas or a list of usual suspects to check on the idle and smoke issue? Are they connected? This is my first full season with a Yamaha and I've come across other threads where people say they should be run with additives like Stabil all season to keep the carbs from gumming up. Can it be expected that the carbs would need adjustment or go out of synch in one season?
if left tilted down blue smoke at start up is normal. oil tends to run downhil past the rings and will collect in the combustion chamber.
the rough running will be most likly a carb issue and I think it should idle closer to 750 or so, but I cant remember the exact number. may be time for a trip to a dealer for a leakdown test,a decarb and check the throttle linkage.
make sure the dealer has a leakdown tester and a techmate or equivalent.
is 5 star meaningless? no. means they watched a 20 minute video.
no there are no standards just like in the american auto industry.
ya got a set of wrenches and u b a techynitian.
I wish there were minimum profeciency standards in my industry. would weed out a lot of crap dealers and techs.
however best the consumer can do is look at the yamaha web site under school certs and find a dealer that trains techs not monkeys.