Re: 9.9 Johnson Carb Question

[enrico-italy]

I also had a troubly experience with this motor.

I bought a used 1976 9.9 with minor issues ( a broken mounting screw, hard to rotate twist grip etc.) four years ago.
The first season I had serious troubles to make it a good runner, because It "sneezed" at idle, so I opened the PW and I replaced seals (the lower one was broken) and rings.

I found on it a couple of Champion L77JC4, so I put on it a new pair of the same plugs.

The rebuilt engine worked better but the plugs lasts no more than two or three hours, then the spark gone.

In the first ten hours of use it burned two sets of L77JC4 and two sets of the raccomanded plugs (UL81J)

Then Garry or Mumbles, I don’t remember, suggest me to try NGK.

I put on it the used set of NGK B7HS I removed from my Yamaha 30D and, (miracle!!), all the issues disapppears.

Three years later, the 9.9 still runs well with the same plugs…