Bad kill switch?

Got to Texoma this morning and motor would not start. Cranking battery a little low so swapped batteries. Not an easy task on my boat but figured it was worth effort. Only thing I did to boat since coming back from last trip was take lanyard off kill switch leaving clip in place. Pulled a plug wire and sure enough no spark. I could tell it was getting no fire so tried bypassing kill switch. Got home and of course it fired right off. Anyone heard of a kill switch working intermittently? Clip was secure and even pulled and held button down by hand.

I have seen where if you bump the shifter a little it will act as if the motor is in gear and not start.

motor turns over. No problem there. I know about the shifter. Mine can be a little tough at times to get in correct position. Motor was just not firing.

Optimax motors are extremely touchy about the cranking battery and their connections. I have seen more problems with the ignition switch than with kill switch on a Mercury. Evinrudes are a different story. If you don`t hear the warning test beeps when you turn the key on, you don`t have 12v to the PCM.

Never had a beep when turning key. I need to get a service manual for the Optimax or at least am owners manual. Original owner did not believe in keeping manuals for anything. Claims he never got one but I think that is bull. I keep owners manuals and any literature that come with anything I buy.

See here..
https://publications.brunswick.com/searchresults.asp?cat=1826

Motor has fired off 3 days in a row. Not sure about battery. Slows 13.2 volts army rest and drops to 9.8 when cranking. I have read different numbers for acceptable voltage drop. Some 10.2 and battery bad others less than 9.5. Not sure what is acceptable. Thinking about buying new just have. Cranking battery new 9/15 so it is getting close.

bad battery.

Edit....let me add...

It has at least one weak cell. It is time to replace it.

Did you check the bulb on your fuel line to see if it would pump up?

About a month ago I was at tackle box and poor guy came in same problem no spark but was evinrude

????????

"Pulled a plug wire and sure enough no spark"

2 weeks ago I put a real good charge on the battery. I bought a new one and threw it in the back of the boat along with some jumper cables judt in case. Boat started fine but voltage with starter engaged read 9.8. Next trip out I put a charge on the battery and nothing. Put the new battery in in Loe's parking lot and what a diff. Voltage does not drop below 12 when cranking. Now I have a benchmark. I have to still pull the old one out and put the new one in the proper spot. Trying to decide if I want to tackle in 30 degree weather this weekend. By the time I put on enough clothes for the cold temps I can hardly get under the console.