Hard throttle stalling Mercury

[bmal]

I have a '92 Merc 115 2+2 outboard on a 18' runabout. Last weekend no problems all three days. This weekend stalled on hard throttle four times throughout the day pulling skiers. I added STP carb treatment before this happened (to 20 gallons) and at the same time lost my gas cap on the road...replacing it with a rubber stopper. The tank has a vent, the chrome gas cap didn't appear to vent. Any replies are appreciated. Thanks in advance.

 

[andy6374]

Re: Hard throttle stalling Mercury

Did you add to much carb treatment?

Try pumping the primer bulb when this happens and if it saves the engine then it's time for a fuel pump rebuild

 

[jddenham]

Re: Hard throttle stalling Mercury

Could be crud in carb bowls, water in carb bowls, or too much STP treatment.

 

[bmal]

Re: Hard throttle stalling Mercury

After it would stall, it would restart and be fine. Crud may have been a issue.

It must have been the STP. The bottle was rated for up to 20 gallons...which was my full tank. I burned about 10 gallons the other day(problem day), and refilled today. I ran for about five hours and it didn't stall once. Any other comments would be appreciated. Maybe I should stick to the sea foam.