2005 yamaha 115 4 stroke losing power

[bay cruiser]

Advice required from Brains Trust! Have a Yamaha 115 4 stroke 2005 model that loses power when hot. Won't go over about 4500 rpm without losing power. You need to feather the throttle to build up the revs - push too quick and it loses power again. Even if you retain the power it won't go more than 5100 rpm when it should be at 5500+. Started happening after the motor had been serviced. Fuel problems are all but ruled out. Any thoughts would be appreciated.

[ozynorts]

If it started happening after a service I would be going straight back to the place you got it serviced and get them to check it out.

[bay cruiser]

Used a mobile mechanic who would not return phone my brother's calls (it's my brothers boat that I have borrowed). That was about six months ago. The problem has persisted.

[Spaniard_King]

Compression test
Check valave clearances
Vapor Seperator needs a clean out

That should sort it or at least put you down the right path