1987 Yamaha outboard

I have a 1987 15 hp outboard that runs rough, and at times is hard to start. Where should I start. The motor runs good at full throttle but rough at *****ing speed and it tends to stall out. The starting issues are intermittant. It usually starts on the first of 2nd pull but the odd time, it takes 4-5 minutes of pulling to get it to go.

Thanks in advance

Mark

[boats.net]

Compression and spark test is always the best place to start. Dirty carbs are the most common cause to hard starting and idle problems.