I assume you have a Briggs & Stratton engine? If so, the spitting is normal - it's part of the compression release mechanism. On the compression stroke, the INLET valve is lifted off it's seat to relieve some of the compression, making it easier to crank. This is only apparent at starting speed. At running speed, this has no effect.
If the engine will not crank, but does rotate up to compression, there is either insufficient current reaching the starter - check battery voltage whilst attempting to crank (should be at LEAST 11V), and check connections at BOTH ends of BOTH battery cables, and the engine chassis ground - OR the starter itself is suspect.
phil_saunders(a)bigfoot.com
Phil Saunders, September 2012
