15hp 2 stroke yamaha outboard

[pritch]

On a 15hp 2 stroke Yamaha outboard what are the 2 small rubber pipes for, that are attached to the cylinders. One goes to the reed valve block, and the other ???????

[robert graham]

Without a photo, my first guess would be those small black rubber oil circulation lines that move oil from various areas to others improving lubrication....

[pritch]

thank you Robert

[pritch]

Hello Robert, may be you can offer some advice to me about my 15hp 2 stroke Yamaha outboard. My problem is that when I start the outboard it will idle OK, but when I advance the throttle the engine will run rough and cut out. I have replaced the Carburettor, CDI unit, high tension coils and leads ( all off another motor that is functioning quite well) and the same problem occurs. I would appreciate any advice on how to eliminate the problem. It becoming quite frustrating. I would appreciate any help that you can offer.

[racerone]

First thing is a compression test.

[pritch]

compression all OK