70hp Hard Starting...Battery issue

[hauchinango]

I have a '88 mode 70hp OMC. I have two new batteries, fully charged. Often, the motor does not seem to crank with enough power to start. Even when using both batteries. It will crank eventually, almost like it catches. Otherwise, just weak starting sound. Any ideas? Thanks in advance.

 

[Silvertip]

Re: 70hp Hard Starting...Battery issue

Start by removing and cleaning both ends of each battery cable and make sure the connections are tight. Also check where the cables enter the terminal ends. Due to flexing and corrosion, these connections cause resistance to current flow that results in poor starter performance. Check back if this doesn't solve the problem.

 

[spucky]

Re: 70hp Hard Starting...Battery issue

I had 1987 Johnson 70 with a similar problem, it was corrosion on the groung lug itself where it threads into the exhaust cover. Try mounting the battery ground on a different bolt.

 

[Joe Reeves]

Re: 70hp Hard Starting...Battery issue

When this happens, feel the cables. If any of them are quite warm or HOT, the problem is usually:<br /><br />A Loose cable - Tight but dirty cable connection - A internally corroded cable.<br /><br />To test the electric starter itself, simply jump the battery cables directly to: Positive to the starter lug, negative to a powerhead ground or to the starter casing itself.