95 xp wont crank with plugs in

[burellii]

a buddy of mine asked me to replace his starter. so i did. the engine will not turn over with the plugs in. if you pull the plugs the engine will turn over. fully charged battery when tried. any and all help would be great since he is taking all his skis to Florida on Thursday evening

 

[dreadloxx]

What voltage do you get when you hit the start button? If it drops down to low you won't have enough juice to turn the fly wheel.