Yamaha 2hp 2BMH Cutting Out

[DOILY]

Why does my 2 stroke Yam always starts and runs perfectly for 15 minutes and then stops. Then it starts normaly but then runs rough and then conks out again after a few seconds. Then starts, conks out, etc. etc.? Could it be over heating? The cooling water exits at the bottom of the leg (I think, as there has never been a tell tail). So how do I know if the impellor is working?

 

[Topcat47]

Two possibilities come to mind: a partially blocked breather in the tank is my Fav, but you my have too much oil in the mix. i'm assuming you have a clean carb.

 

[alahol2]

Could it be over heating? The cooling water exits at the bottom of the leg (I think, as there has never been a tell tail). So how do I know if the impellor is working?

It's possible it's overheating, there should be a decent 'spray' of cooling water coming out of the exhaust relief port on the back of the leg above the waterline.
See the first bit of this movie... http://www.youtube.com/watch?v=NWPW61J2Ol4

 

[VicS]

Even with no tell tale you should see some water, at least a mist or a few droplets, being blown out from the exhaust relief port on the back of the leg ( little cover over it usually)

If you cannot touch and maintain contact with the cylinder head for a short while ( except close to the plug) it is probably overheating
If any paint on the head is discoloured its probably overheating.

If you dont know when the impeller was changed change it but the water ways could be clogged up and be in need of unclogging

Check the fuel supply/ flow to the carb. There's a little filter I think you will find in the tank on top of the fuel tap that could be getting blocked