My motor on my boat is a 1995 Yamaha Vpro 150. We were riding today at around 5500 rpms then all the sudden it went down to 5000 rpms. I cant get it to get back to 5500 rpms and now it is very slow to get on plane. Checked both fuel filters and they were both clean. Any suggestions on why it seems to have lost power?
Post by Humperdink on Aug 15, 2015 18:54:53 GMT -1
Check compression first. Whats the coil/carb setup on these things. for example if you have 3 carbs and 6 cylinders you will find 2 plugs with obvious clues in their appearance if you have one main jet boogered up. always check spark and pull plugs to observe their condition. The color of the plug can often identify the cylinder(s) or carb that is acting up and give some insight as to whats going on in there. Anything from clogged jets to weak coil packs to clogged water jackets and blown headgaskets and crank seals can affect your max rpm. Recently I bought an allegedly broken outboard to break down for my parts store and discovered it had an acorn in the cam follower. Now my dad uses it as a kicker. check all linkages and vital signs (spark and compression, timing so on) and linkages and move on from there.
I am fairly versed in small outboards but only buy/work on the ones i can lift by myself so I dont know what your setup is like and need more info to give you good advice.