1986 40hp Chirping/Sneezing at start up

Hi,

I have a 1986 40hp that has been chirping/sneezing at start up for the past few years. It required extra toggles of the choke switch to keep it running until warm. Once it warmed up it would run great and start fine after being shutdown.

It now does the same chirping /sneezing at startup, takes more choke to keep running, runs poorly at cruise and stalls when back at idle speed.

Reed valves?
Carb kit overhaul?
Ideas?

Thank you for the feedback. I'll rebuild the carbs.

[rossmore40]

chirping

I have about a 1998 - 2000 model Yamaha 40 HP 2-stroke, elect. start. It does the chirping thing. One repairman said it needed the carbs adjusted. He did that. It still chirped. I took it back, then he said that the carbs needed to be removed and cleaned. He did that. Then, it started chirping again. I took it to another Yamaha repairman. He said that it was because the carbs were out of sync. It has 3 carbs, stacked. He synchronized the carbs and it ran quitely for about 6 months or more, then it started chirping again, so, maybe he was onto something. One man on this forum seemed to think it was because the crankshaft bearings needed to be replaced. I am not so sure about that; but, I guess anything is possible because causes of chirping and the various types of chirping could be different for different motors. But, mine sounds like it is a carb problem. Any ideas from someone more knowledgeable?

[99yam40]

It would be best for you to start a new thread instead of adding onto an old one.

chirping (lean sneeze) Is usually caused by plugging jet/passages in carbs.
Clean well and then let more junk into them from tank,lines,primer bulb,fuel pump, etc. and you will have to clean them again.
Always follow the link and sync procedure after reinstalling the carbs