84 Mercury 50 HP problem

[USDA3]

Been having problems with the 84 merc 50 HP outboard for about the last year. Most of the time when started, the motor will run on only half the cylinders. Sometimes all cylinders will kick in after a few minutes sometimes they don't. We've replaced plugs, wires, and have tried readjusting the carbs. We've also checked and were getting juice to the plugs. Not sure where to go from here but anyone who has experienced these types of problems, or may know what step to take, I would greatly appreciate it!

thanks!

[Surface Tension]

Could be your fouling plugs from too much choke time or the carb(s)is dirty with a bad inlet needle/seat or float adjustment. I'd also do a compression test.

[iffy]

Possibly you have a stator, trigger or CD unit that is operating intermittantly. Those are high ticket items though, and you might want to get them checked at a repair shop before just replacing them. The only other explanation I can think of would be very dirty carbs.

[boatfixer]

sounds like a switch box to me, but like iffy said, this needs to be tested by someone who has experience in doing so.

[wrench]

Ill second the switch box. Exact same problem on my same motor. $275.00 dollars later runs fine. Mercury dealer says there is no way to test them.

[mr wizard]

Had the same problem - switch box fixed it.

[BoxMN]

Easy little item, though most likely not it, is to make sure the vent on the tank is fully open. It can vibrate shut, or part shut, and fuel flow slows/stops. Most liekly it would totally stall, but easy and quick thing to check for.

Our 82 50hp is still running strong after tons of use, and only water pumps and plugs so far. This is a great motor model, though it is thirsty huh? But smooth. We use it now mostly for duck hunitng into the ice up period, and it runs flawlessly. I'd do the switch box first without even thinking, as that seems likely.