70 hp evenrude Engine surges

Hi all,<br /><br />I have a 70 hp evenrude outboard engine.<br />Here is my history and problems to date.<br />The boat was in storage last winter without being winterized. (my girl friends boat that is) She didn't know that you have to winterize it.<br />Anyway I took the boat out of storage and put it in the water. Ok here's what happened.<br />Started fine. put in gear and start accelerating.<br />1200 rpm boat dies. try again same result. try over and over same problem. all of a sudden works great. after reving up in nutreal to about 4000 rpm. press in the choke runs great for a while. <br />Then engine surges at high speed. Turn off engine and start all over again with engine dying at 1200 rpm. after a couple of times decide to call Marine shop that worked on it last year. They say carbs need cleaning all gummed up. Called another marine shop they said bring it in. Ok I bring it in and they tell me its the antisiphon valve and they have to take out the seats and floor to get in and replace it or repair it. I say ok lets do it after all they are the experts right. (Ha) $230 dollars later they call and say its done runs great. They took it to the river and ran perfectly. Later I find out the left it on the trailer and put a load wheel on it. Any way I take it home, 80 miles one way by the way. Put it in the water and looked forward to a great day of skiing, start up the boat and runs great at idle. Start off and does not die like before at 1200 rpm. I am estatic, cool they fixed the problem. Up to plane and here we go again it starts surging again with the throttle full out rpms start dropping and finally I am stopped in the water with the throttle all the way down and rpm at 1100. Boy am I pissed. Before I call the guy at the marine shop I would like to get your opinions! the engine model number is e70tlery serial number is g 0364220 and its a 1995 sunbird.<br />Thanks<br />Bob