Hello Pete,

Always check that batteries are in good condition and have a full charge.

Check that you have good, clean cable connections between both the positive and negative battery terminals and both cable connections at the engine.

Pull apart the 11 pin harness connection plug at the back of the engine and inspect for corrosion at the terminals. If corrosion is evident, clean and reconnect with grease applied to the terminals.

If you have the deluxe panel, also check the plug at the panel end of the harness for corrosion.

I believe that if you follow these steps you will find your problem.