# 15HP Merc 4s Struggling to get High RPM



## William Odling (Jan 8, 2020)

Thats a drastic difference, you need to go over all that you did to ensure you did it correctly. (I'm assuming you did the work?)

Was the carb replaced for a new one? If it was used are you certain it wasn't faulty? What was the reason for replacement?


----------



## Skiffy Lube (May 22, 2020)

@William Odling Carb was replaced with a brand new one. Replaced because the diaphragm was not operating on the old one, and choke was frozen.


----------



## William Odling (Jan 8, 2020)

When you cleaned the plugs did you damage them in any way? Bend the gap closed? You are sure the connections are all tight on the cables and the plug leads?

It could be that its something else unrelated to what you did and a new issue....


----------



## Mike Haydon (Dec 19, 2019)

If the weight is the same I wouldn't think it has anything to do with prop. I would check your first guess first. The throttle pin. The jetting could be different in the new carb. Might use the the old jet in the new carb?


----------

