Problems with 28HP

[hksubaru]

Hi there, great site, done a search but still a bit stuck.

I have a yamaha 28hp longshaft outboard, all seemed to be fine last year until now when i took it out, it starts and runs but doesn't go fast or high revving like before, seems to push the boat along slower than walking pace!

Whilst searching i was thinking it could be the jets or carbs? what are the symptons of blocked parts? Also is it easy for a novice to do? never worked on boats but i guess engines are engines right?

[hksubaru]

found out it was the carb not moving properly, got it sorted now, really don't know what the mechanic has done as it keeps on puffing out a lot of smoke once it's running its in gear in about 2 mins and cuts off... then nothing works, doesn't even turn over.

Leave it for a while and it will start again.

Any ideas?