no rpm

[dave connor]

I have a 74 Johnson Powerhead II 50 hp that idles fine and I have replaced the CD Box, however when I advance the throttle forward I have no increase in rpm. What should I look for that is stopping it from increasing rpm ? Tks. Dave.

 

[jtexas]

Re: no rpm

welcome to iboats.

advancing the throttle does two things: 1. advance the spark timing, and B. open the carburetor throttle valves. Either one of which should cause the RPM's to increase, but both of which are necessary for the engine to develop enough power to actually push the boat.

look on the starboard side of the engine, see if anything moves when you push the throttle control forward.

 

[Barnacle_Bill]

Re: no rpm

Check your linkage to the carbs to be sure its working.

 

[Silvertip]

Re: no rpm

There is a very specific procedure called "link & sync" that adjusts all of the timing and throttle linkages. You need a service manual specific to your engine to do this correctly. Miss a step and the end result is wrong.

 

[Barnacle_Bill]

Re: no rpm

welcome to iboats.

advancing the throttle does two things: 1. advance the spark timing, and B. open the carburetor throttle valves. Either one of which should cause the RPM's to increase, but both of which are necessary for the engine to develop enough power to actually push the boat.

look on the starboard side of the engine, see if anything moves when you push the throttle control forward.

Starboard side?

 

[jtexas]

Re: no rpm

Starboard side?

that's where it is on my motor..................

 

[HighTrim]

Re: no rpm

Starboard sounds right to me, thats where mine have been...