I have a RV6 with a O360A1A. For the past two months I have had an intermitent problem with my starter. Typically the engine starts fine when it is cold. After I have flown for a 1/2 hour or so, ocassionally I will get is a buzzing noise and a slight prop movement . Sometimes the problem will last for just a couple of seconds, other times I have to wait for several minutes before it will start.

I know this sounds like a short. The problem I have is that by the time I can get the cowling off and get a multimeter on it, it is too late. In the past month I have replaced the starter, battery, Starter Solinoid, Master Relay and battery cable from Starter Solinoid to Starter. The only thing left is the two Battery cables and ground wire.

Any Suggestions???
 
If you are using the airframe for the ground, then I would make sure you have a good connection. I believe loose grounds cause more problems than just about anything else. Another thing to check is the crimp at all cable connectors, including the connections to the battery terminals. (Both positive and ground.) In a high heat situation, you will need to draw more from the battery, so I really suspect a poor connection in one or more spot.
Good luck.
 
Steve is right. Most electrical problems are caused by bad grounds. Do you have a good ground cable between the engine and airframe. This cable must be as big as the starter cable. Current is the same throughout the circuit. In other words, what goes in must come out.