83 2 Stroke 50 HP Mariner Surging Problem

I just started having a surging problem with my engine at speed yesterday while on my way back in for the day. To stop the problem i had to pretty continually keep pumping the fuel bulb to keep a stead supply of fuel going to the engine. Today I replaced the bulb but it did not make a difference. I'm pretty sure I replaced the fuel pump diaphragms when I rebuilt the carbs last fall. I have 2 steel 5 gallon tanks. Today, with the tank I was using yesterday when this problem started, which is about 1/4 full I could not get the engine to run up to speed at all. At full throttle it would hardly move and I assumed it was not getting much fuel. I immediately switched to the second tank that was full. Right away I thought the problem was solved and it ran ok but after about 10 minutes it also started surging near full throttle unless i pumped the bulb again. I backed it down a bit to say 3/4 and it ran ok. On the way back in an couple hours later with about 1/2 tank left it again started surging. I had to keep pumping the bulb to make it back without surging. Now I'm wondering if there are issues with the fuel tanks? Anyone else experience this? Any thoughts out there??

Re: 83 2 Stroke 50 HP Mariner Surging Problem

some years ago i had same problem same motor .... ended up being a combination between week fuel pump and the needle seat on the float was sticking ,causing a surge when it popped loose occasionally .... not sure if this is you problem,but it was mine .... replaced fuel pump even thou it was fairly new and the bowl valve needle and seat ran even better than before it surged ....my 2 cents

good tips ..I did clean and rebuild the carbs a year or so ago and replaced the floats. Other than that is there actually an external gas pump also I missed? I've been tied up and haven't tried to adjust the idle mixtures yet.