i have an older 70's Evinrude 9.5hp motor that was running fine one day and all of a sudden started to misfire and surge so i changed the plugs. it still misses and surges and will only go just over idle. it also will only run on choke now... do you think this is a fuel delivery problem, or an ignition problem? i will check the points tomorrow and open up the carbs to see if they are clogged or dirty. any help is greatly appreciated