I own a Yamaha 9.9 fourstroke (1998) motor which I use on a pontoon boat. 1st its a bit hard to start after sitting for a couple of days, but after cranking for about 10 seconds it goes. The real problem is it will be running along just fine at any speed then slow to about half speed, sounds like one cylinder cuts out. This will last for a few minutes and then run well for awhile then do it a gain. Every now and then the motor will slow to half speed then come to a stop,after we restart it will run fine till the next time. I have changed the fuel filter, plugs (a couple times), coil and new gas. All hoses look fine. Can't see any problems with bad wires.Any type of test I can do to identify the problem? <br />Sure would appreciate any help I can get.
