Yamaha 20 hp 2 Smoke improved
Had this engine for a month or more and used it for around 12 hours. It looks pretty mint and has done little work and runs great 99% of the time. But some times on tick over it popes and stalls..
I check plugs and drained the fuel bowl, cleaned the fuel filter etc, but still the same. i.e. almost perfect. Blew out the pilot jet areas from the out side the carb.. Putting the screws back were I found them 1.5 turns out each. Still the same.
So I thought I would take the carbs off and clean them properly, but noticed a label inside the engine cover that the pilot jets should be 2.5 turns out.
I set these (takes 10 seconds) and the motor ticks over and revs from 750 rpm like a sports bike. Instant and crisp, and ticks over with so issues at all.
Maybe the last owner adjusted them for some reason or a service shop just set them wrong??