2 stroke spitting some gas

[Tips Up]

I have 1991 2 stroke, oil injected 90 hp yamaha.
Has always run well. I change leg oil and plugs each season.

I've noticed recently it smokes more when cold at start up and some fuel seems to be bubbling to surface around the motor when idling. From exhaust?

Maybe needs carb adjustments or?
Thoughts?

Still runs well. Nothing else seems different

Thanks.
Tips

 

[Aces]

might be a reed valve?

 

[Tips Up]

Thanks
Did some googling on reed valve. Could be it.
If so is it safe to run it until I can get it in to a shop ?

Any other thoughts on possible issues?

 

[Tidal Chaos]

I would recommend going on the Hull Truth website and do a search; I have been having some minor issues with my Yamaha 2 strokes and the info I have read on that website has been more than helpful self diagnosing things. If your motor has low pressure pumps; I would recommend pulling them off and seeing if one of the diaphragm's is leaking dumping fuel into an exhaust port. Also older Yamaha's can be adjusted to how much oil is being dumped into the system; as they get older they need to be adjusted more frequently apparently. In my case I also found out that they tend to smoke more on start up because certain cylinders aren't firing on start up and they drop a cylinder as they go up in RPM.

Like I said; do some reading on the Hull Truth, you will find out a diagnosis on there that won't cost you anything other than a bunch of time! Good luck.

 

[profisher]

A reed valve is not that likely. They rarely give any problems and I've only heard of them getting damaged when engines suffer catastrophic failure and major backfiring occurs resulting in them getting bent. A bad fuel pump diaphragm will allow excess fuel into the engine and is way more likely to be at fault. They are relatively cheap and easy to replace and if it hasn't been replaced in a few years it should be done anyway. I change mine every 5 years to prevent having one fail during my busy summer season ans when even small easy repair jobs are a pain in the butt to when the boat is in the water.

 

[Scoopy]

Could be as simple as a sticky float. I would drop the bowls and do a light carb clean, see if it solves it.