90 Merc 20hp, same problem as last year.. runs on one cylinder only

[deejathome]

Hi everyone, another year another string of posts from me. So Im still having issues like I did last fall. My 20 hp merc will only run on one cylinder when first started. If I keep running it on one, when it gets hot it starts to make the dead cylinder sputter and then it leaps up to speed on both after about 4 minutes of that. Am I explaining it ok? <br /><br />SO last year, with the assistance of this board (thank you very much) I tried a couple of things. First thing was a new tank hose, done. Then I rebuilt the carb and gave it a good cleaning and a good blow out. Seemed to help a bit, but didnt take away the problem completely. So then I pulled off the electrical connections to the coils and cleaned off the metal for a better connection. This fixed it for a while too, but it's back.<br /><br />My question: Should I break down and drop it on a dealer to go through, or is there something else I can try? I was thinking maybe a new coil to that cylinder? Appreciate anyones input and suggestions.<br /><br /><br />DJ<br />Winnipeg MB

 

[achris]

Re: 90 Merc 20hp, same problem as last year.. runs on one cylinder only

Which cylinder is playing up? Top or bottom?<br /><br />I would doubt it was anything to do with fuel because both cylinders are fed from the one carb. Coil or switchbox, could be. I would also be looking at crankshaft seals. It's about the age to have them looked at, also exhaust cover gaskets....<br /><br />Chris...........