Intermittent starting problem with 2005 Mercury 175 Optimax

Appreciate any help with the following problem. I have a 2005 Mercury 175 Optimax and have had a starting problem on two different occasions. After fishing all day and the motor starting a dozen or more times I turned the key and nothing to the starter.The alarm bell beeped and you could hear the first relay make noise but nothing after that. I checked the fuses at the motor all were good. After we pulled the boat to the dock we let it sit for about a 1/2 hr and it fired up fine and i shut it off and restarted it 5 or 6 times no problem. Took the boat home and hooked up water could not get it to duplicate it started fine. Next time out similar situation boat started fine all day after numerous starts again bell sounded relay made noise and no juice to starter.The other relays did not make noise.After an hour or so Boat started and continued to start which I did 5 or 6 times.Problem is intermittent so hard to diagnose. Any help is appreciated.

Re: Intermittent starting problem with 2005 Mercury 175 Optimax

Intermittent problems can be tough to diagnose, you have to catch it while it fails to be certain.

I suspect the contacts in the starter relay have a slightly burnt spot, when the contact washer rotates to the burnt position it fails connection and the starter will not crank. Hit the key a time or two and the washer rotates and contacts an unburnt area and all seems fine again.

The proof is to have a test light or volt meter wired to the starter side of the relay, and either an assistant of a remote starter button. Bump the key/starter button 100 times until it fails, when it fails, hold the key/button and see it the test light/meter is out, proving the poor contact in the relay.

Re: Intermittent starting problem with 2005 Mercury 175 Optimax

Charlie, I appreciate your advice . I will give a try and let you know what I find.Thanks Again. Mike