1978 55hp Johnson surging.

[woodnknots]

I have a twin outboard setup consisting of 2 55hp Johnsons. The starboard motor has no issues, and sounds great. The port works, but always runs at a much lower tone than the starboard. I say tone, because that's the best way to describe it. The starboard sounds just like you'd want your outboard to sound, and the port just sounds like it's lazy, or just smoked a joint, or something.

Anyway, when I'm running at WOT on both motors, the port will every once in a while just start surging on me. I can usually back off the throttle, check it out, and then go again within about 15-20 seconds or so. It sounds like fuel to me when it surges. The first time it happened, I unscrewed the cover for the fuel pump to check the screen (it was clean) and put it back on, and the motor ran like a champ for the next several times out on the water. Tonight it started it's crap again. I backed off on the throttle, played with it, and it eventually worked okay again. BUT... When I advanced the throttle on both motors evenly, the port was obviously lagging behind in rpm's. They both got to wot, but you could hear the port was lagging behind on the way up there.

Any ideas? I'm thinking I may have a timing problem, or a carb issue that is intermittent, or a combination of problems.

Help, PLEASE!! I'm deploying the first part of November, and striper season is coming!!

 

[bgbass.1]

Re: 1978 55hp Johnson surging.

it sounds like when you open the throttle its not opening all the way at times check to see if its opening to full throttle at all times or is hanging up.the othe thing to check when it does it squeeze primer ball if it straightens out fuel pump no good
mike

 

[woodnknots]

Re: 1978 55hp Johnson surging.

the thing to check when it does it squeeze primer ball if it straightens out fuel pump no good
mike

I've tried squeezing the primer ball, no luck. I WAS thinking that there may be an intermittent clog in a needle or something, but I just don't think that would cause the lazy sounding idle. The motor also shakes at low RPM much more than the other.

I'm going to buy a timing light today (I need one anyway) and see if the timing is off.

Thanks for the reply, any other ideas?

 

[woodnknots]

Re: 1978 55hp Johnson surging.

I just re-read the post... Any idea why the throttle might not be opening up all the way at times? I have checked the cable linkages, and everything is solid.

 

[woodnknots]

Re: 1978 55hp Johnson surging.

After talking to my Dad, new theory. Intermittent weak/no spark.

Any thoughts on this idea? I've only got one CD unit, so no other one to troubleshoot with, except pulling it off the other motor, not sure I want to risk doing that.