Starter issue

[bruce spencer]

I have a 1972 38' double cabin with twin Detroit 8v 53's. Just replaced starboard battery due to staring issues. Engine still won't turn without using parallel selector. After running a while, the starter engages without parallel selector. Any suggestions as to the problem?

[Pascal]

Start with the basics: check all connections for corrosion incl the battery switch and negative connection to engine. If that doesn’t solve it, starter could be getting tired

[Boatsb]

Probably bad cables and or starter. If the cables are original dont even try to fix them.

[PATRICK J RICCI]

you have been given good advise from some members with regard to battery cables, connection and weak starter. 8v53 engines have a 21:1 compression ratio and need 100 percent of a 12 volt system to start particularly with 12 volt as opposed to 24vdc. just be sure that you are not getting water back into the engine from a failed water jacketed exhaust riser causing a hydraulic lock. if thats the case, further damage will occur. if you need risers, i have a pair real reasonable.

[scottinsydney]

Same issue on my engines late last year. Only solenoid clicked when starter button pressed.

Removed all battery connections from starter, the block grounds and solenoids. Cleaned c onnections with Emerry paper and WD40'd down ends of cables. Now both motors offer easy starts from cold.

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Question.... what causes verdigris to occur on some battery posts and battery connections, while others beside remain clean? Does Vaseline jelly successfully stop corrosion on battery terminals and posts? Or is there a special product for this?