Engine starting problem

[Pdemajo]

I have a volvo penta tmd-22p engine ( typical sailing boat 85hp engine) on my sailing boat. It normally starts perfectly except when, after running it for a good hour i stop, switch it off for a whIle (2hrs or more) and then try to start it. Its as if there is no electrical connection as turining the key has no effect. The batteries would be perfectly charged.
The only way i can start it again is if i switch off the battery banks from the main switches for a minute and thenswitch them on again. After that the engine starts perfectly the moment i turn the key.
Has anyone come across this problem before?

[Neptune's Gear]

A voltage drop test will confirm, but I'd suspect a voltage drop across the battery switch you are turning off and on. Easy test. Use a multimeter on volts, pos lead on the + battery terminal neg lead first the batt side of the switch while turning the key, then the starter side of the switch. Both readings should be under 1/2 a volt max. The nearer zero the better.

[Pdemajo]

Originally Posted by Neptune's Gear

A voltage drop test will confirm, but I'd suspect a voltage drop across the battery switch you are turning off and on. Easy test. Use a multimeter on volts, pos lead on the + battery terminal neg lead first the batt side of the switch while turning the key, then the starter side of the switch. Both readings should be under 1/2 a volt max. The nearer zero the better.

Ill try it and let you know! Thank you!