On yacht - Johnson 9.9 '94 Missing at speed

[BJones]

On yacht - Johnson 9.9 '94 Missing at Speed<br />The motor idles ok. Above half throttle starts missing after several seconds, giving a very low power output - very bad trying to slow down in reverse with strong breeze from astern. Have replaced plugs, connectors at both ends of fuel lead (air leaks?), flushed out fuel tank, cleaned out carby bowl (some rusty water in it), blown out jets that I could find. <br />Local dealer on phone suggest powerpack fault, very expensive - $430us. Any other (cheaper) ideas?<br /><br />Wonderful forum, everything here but an answer to my problem.

 

[Waterbugtoo]

Re: On yacht - Johnson 9.9 '94 Missing at speed

Since you say you had "rusty water" in the carb.....and you are absolutely sure there is no more in tank, carb bowl, or carb passages, then put a timing light on plug wire/s while running. Do you see the light become irratic when it starts missing?<br /><br />

 

[Yepblaze]

Re: On yacht - Johnson 9.9 '94 Missing at speed

You probably have residual crud in main jet alnong with additional watery rusy crap in bowl again. <br /><br />Find the main jet in carb, and emusion tube, if used and clean them thoroughly. At that time you can view bowl contents and see if all water is out of the system.