Replaced the dynamo in my B7610 HST. Put in a 40 amp alternator kit which I purchased from dealer. Followed instructions to install. Now the starter cranks the engine just fine. However, the engine will not catch and run. I am getting ready to uninstall and put dynamo back in, just to see if it starts. Prior to alternator installation, no problems of any kind starting, electrical or anything else. Battery is strong. Any ideas? Thanks