hi, i have a craftsman lawn mower model 917.275754 with a briggs 18.5 horse that cranks but wont start it has fresh gas and oil,new plug and fuel filter.I have removed the gas tank and carb and cleaned both, it has fire and compression,i checked the fuel sylenoid and it appears to work fine but i removed the fuel sylenoid and replaced it with a bolt and it started and ran fine for about 200 feet and quit, so would this be as simple as a rebuild kit for the carb or does the fuel syleniod play a bigger role in the operation of the carb than just safety?