I'm fixing a couple of mowers for a friend. One is a B&S 4.5 on a Bolens 21 inch push mower. It has the plastic carb on it. I did a oil change, plug, air filter . It had been sitting a year or so and would not start. I got it to start and die several times. Took the tank and carb assy off and separated the carb from the tank. I cleaned the passageways in the carb with carb cleaner and some comp air. Re-assembled it and put it back on the mower. Starts fine now, but runs at a high rpm. Not quite to where you'd think the governor was stuck or kicking in. Seems awful fast for this type of carb. THere no speed control on this mower at all. It must run at one speed. I checked the linkage to the governor and it works fine. Just seems too high for me. Any ideas or suggestions?