15 hp Mercury outboard, where to start

[atoetz]

Just bought a 15 hp merc outboard, 1991 per the owner. SN 0D039564. it is spotless, barely used, was on a dinghy for large boat, probably about 5 hrs on it. has not been run in 2 yrs. Pulling starter and it turns over easily but nothing. Tried some starting fluid also. Not even a sputter. There is what appears to be a hookup for a lanyard/kill switch but is broken off. Is there some way this is keeping it from sparking electrically? Where should I start, what steps to follow to test different aspects of this motor.

Thanks,
Aaron

 

[stingertrey]

Re: 15 hp Mercury outboard, where to start

I haven't posted on this site in a while man lol.. but first assure you are getting spark.. remove the plugs and put a plug tester on them and it should jump a 3/8's gap with a big blue spark.. or the old fashioned way just ground it to a head bolt and pull.. u will see spark. IF you are getting spark move on to fuel circuit.. If its been 2 years its definitely needing a carb cleaning so do that before moving ahead. then if it doesn't crank make sure your fuel pump is working.. disconnect fuel line that exits the fuel pump and give the rope a pull.. fuel should spirt out on the compression. Make sure fuel filter isn't clogged. Last but not least. check compression. If you have spark. compression. fuel. you have a running motor

 

[atoetz]

Re: 15 hp Mercury outboard, where to start

ok, will give that a try tonight. are you familiar with that type of kill switch on these motors? it is a little square on the front of the unit, says "run" at the top and "stop" at the bottom, has a rubber gasket/boot type thing with nothing protruding. is it possible this is stuck in stop position? is there a way to bypass that?

 

[Mi duckdown]

Re: 15 hp Mercury outboard, where to start

The kill switch is probably the cause.
AND QUIT USING STARTING FLUID.
Use a 50/1 gas oil mixture if you must.

 

[atoetz]

Re: 15 hp Mercury outboard, where to start

ok, if that switch is a possible cause, what can i do to bypass it or eliminate it from the wiring all together? or easier to just replace that kill switch mechanism?

 

[windy5849]

Re: 15 hp Mercury outboard, where to start

The kill switch grounds out the ignition when the lanyard is pulled.Just disconnect the wires from this switch and insure they are not touching anything metal.I ASSUME you have a kill switch on the tiller handle that you can use if/when the engine fires up.Hope this helps.

 

[atoetz]

Re: 15 hp Mercury outboard, where to start

yes, there is a push button kill at end of tiller. inside the lanyard kill switch was a metal spring, i pulled that out, hooked up in line spark tester and now have a spark. engine will turn over, and try to run for up to about 20 seconds. runs very rough, shakes, sputters and coughs but won't do anything more. now i'm thinking fuel and carb issues? or could it be timing?

 

[windy5849]

Re: 15 hp Mercury outboard, where to start

Glad to hear one of your problems are solved.Your motor is 20 years old,even with low hours, and will definitely need the carb cleaned or rebuilt with a carb kit.Untreated fuel during it's storage could have added to the problem.Unless the engine was disassembled,the timing should still be ok and not affect starting.It would also be a good idea to put a new impeller in the water pump before running it.Hope this helps - good luck.