ENGINE SURGING

[Fireman81]

Hello,
I have a 1992 Johnson 40 hp outboard that starts fine and idles fine but when I take it out on the water I can get up to speed for the first couple hundred yds or so then it starts surging. My guess is a dirty carb. what else could cause this?

 

[racerone]

Overheating ?----Have you checked water pump impeller ?---Or perhaps run with a different tank and hose.

 

[Chris1956]

Pump the primer bulb and see if the surging stops. If so, rebuild the fuel pump, clean the fuel filters, make sure the tank vent is clear.

 

[Fireman81]

I have not checked the impeller but I do have a steady stream coming out.
Also have not checked a different hose or tank. I forgot to mention that I have gas coming out the overflow breather on one of the carbs for sure.