sheltz32tt
New member
Hey everyone first post and new to the boating world. I purchased a 2008 lund 12ft boat with a 2008 Mercury 15hp 4 stroke engine. When I purchased the boat the motor starts pretty quickly and runs perfect at idle even while revving. When it is put into forward the boat doesn't have the speed at WOT that it should have, 5mph tops. I had an uncle clean the carburetor and I changed the oil which was slightly over full. Some fresh 91 octane non ethanol fuel was put into the tank for the next ride. Took it for a spin and same issue happened. Strangely though, after an hour or so of riding around the boat magically came to life for 10-15 seconds. The RPMS seemed to get higher and the boat was rapidly speeding up, then unfortunately slowed down and back to 5mph. I loosened the gas tank cap thinking it may have been vapor lock and it didn't help. The primer bulb stays pretty much inflated the whole time with very little softness. Pinching the fuel line trying to starve it of fuel didn't seem to have much of an affect either. Any ideas?