Starboard engine slow to turn over

[270Dancer]

I have a 1991 270 Sundancer with twim 4.5L engines. I have 3 batteries, 2 are on the port side and 1 on the starboard side. The starboard engine turned over very slow when trying to start. If I use the emergency start switch it turns over with no problem. Thinking it was a battery, i replaced the battery on teh starboard side, but this did not cure the problem. Is it possible that 1 of the 2 batteries on the Port side start the starboard engine?

Does this mean that the starboard battery is only to power accessories?

 

[300 da]

Anything is possible. Sea Ray used different battery/switch set ups in different years. On my 1995 I unhooked each battery and figured out which battery was house, start, combined, etc. by trial and error. You can also follow the positive battery leads into your battery switches (if you have one or two). It is a good idea to try and figure out your 12v system, wiring, and battery charging. The better you understand the whole system the longer life you will get from your batteries and the confidenceto to know you will be able to start each engine. Hope this helps.