70hp Mercury Starting Issues

[Maine Ducker]

Hi all,

I recently purchased a 16' bass boat with a 1979 70hp Mercury. The boat hasn't been used in about a year. The boat and engine are in super condition (engine was rebuilt a couple years ago) but I'm having trouble getting it started. I get the "click" when turning the key and thought it must be the started solenoid. I put a new one in and still have the same problem. I pulled the starter out and stuck the juice to it and she spins right up no problem. So my question is, could the starter still be bad or is the problem elsewhere? Like I said, if I bypass the solenoid I can get the starter to spin and crank the engine but not by turning the ignition key. Thanks for any help on the matter!

 

[JB]

Re: 70hp Mercury Starting Issues

Your problem is almost certainly poor connection in the starter high current circuit, Ducker.

Go to the Engine FAQs Forum and do the troubleshooting for the starter circuit in "Outboard won't start".

Your symptoms suggest a bad solenoid, but my guess is resistance in connections.

 

[Maine Ducker]

Re: 70hp Mercury Starting Issues

Thanks for the suggestions. I'm going to replace the starter and see if that helps. I'm pretty sure the starter is original so I'm sure it's toast.

 

[Dunaruna]

Re: 70hp Mercury Starting Issues

Before you spend any money, charge the battery and clean the terminals with a wire brush.

 

[hkeiner]

Re: 70hp Mercury Starting Issues

It is generally cheaper and less frustrating to perform some troubleshooting before replacing expensive parts on a hunch. For troubleshooting the starter system, a multi-meter and a systematic troubleshooting approach should help you determine the problem. It could be something simple and cheap to fix, such as a corroded connection. The below guide is for a 150HP V6, which is different than for your motor, but the troubleshooting logic would be the same.

A quick check is to use a jumper cable to jump from the battery + post directly to the starter and see if it spins the motor OK then. Using a different battery (say from your car) would also eliminate the possibility of a weak battery.

Just my thoughts...

 

[Maine Ducker]

Re: 70hp Mercury Starting Issues

Thanks for all the advice! I think I figured out what is going on. I pulled the starter out and brought it inside for a few days. It warmed up and turned nicely. After putting it back in it works fine. So I guess the cold is freezing it up. I'm not sure if there's water in there or what but I guess the best thing to do is replace/rebuild it.