Hi chaps.

I have a friend who has just purchased a ys 91 four stroke. It looks similar to the 110 with the big air box on the back.
The problem is getting it started. It's a real pig to start taking quite a while, but when it does finally start it runs very well.
The plumbing is all ok and so is the fuel and plug. We know the motor is getting fuel as it drips from the carb once primed.
I have 2 YS 140's one is a pressurized tank sport and the other is a DZ. Both of which are a pleasure to operate and start.
As I am used to running and setting up these engines I am at a loss as to why this particular engine is so reluctant to start.
Please can anyone shed some light on this, am I doing something wrong but can't see it.

James.