That's normal la. When you spray cleaners into your TB & intake, the start up will be more difficult and will need a bit persistent cranking. But using carb cleaner, it's better to spray when engine is on. Btw rather than using carb cleaner, should've used foam type cleaner like GZox or DCS cause they are even stronger cleaners and would be easier to start up even when you spray when engine is off. I used to do this every 10K myself, and I even spray GZox directly inside the combustion chamber of each cylinder thru the spark plug holes.