mercury 50 outboard turns over only sporadically

[chuckwest]

Hi, <br />I've got a 9-year old Mercury 50 HP on a pontoon boat, and this summer it's only been starting sporadically. For instance yesterday, I went to start her up, turned over for about 5 seconds and didn't catch, and the next time I turn the key to start, nothing happened. Waited 5 minutes and got it to start. Today I go out, turn the key to start and nothing happens. Not a peep. Try again and again and it doesn't turn over. The battery shows at least 10 volts, the engine lowers and raises.... <br /><br />The marina just installed a new battery on Friday because they thought that was the problem. Any help would be appreciated!<br /><br />Chucky

 

[Silvertip]

Re: mercury 50 outboard turns over only sporadically

If the battery is showing 10 volts, you have the answer to the problem. You need to either charge the battery or replace it if a load test shows its bad. Before you pull the battery however, measure voltage again -- but do the test while you have the key in the START position. Bet it drops to nearly "0". When you get it running again, measure the voltage with the engine at a fast idle (1500 - 2000 RPM). It should show 13.5 volts or more. If its 12.6 or less, the charging system is not working.

 

[chuckwest]

Re: mercury 50 outboard turns over only sporadically

Thanks for the quick reply! So I took a proper multi-meter out to the boat to check on what you said. Here is what I found:<br /><br />Reads about 12 volts (it's analog) when I test the terminals on the battery. When I turn the key to Start and check the battery, the voltage does not change at all.<br /><br />When I turn the key all I hear is a quiet, single click coming from the engine.<br /><br />Anymore ideas?? <br /><br />Thanks,<br /><br />Chucky

 

[Coolmaker]

Re: mercury 50 outboard turns over only sporadically

Could be a bad connection at the battery, starter solenoid, starter itself or at the ground lug on the motor.

 

[daniel11077]

Re: mercury 50 outboard turns over only sporadically

not an expert but did you check to see if your starter is engaging the flywheel when your trying to start the motor. watch when you go to start and see if the starter kicks up or not.

 

[bigbrownbuku]

Re: mercury 50 outboard turns over only sporadically

try shorting your starter solenoid. does the engine crank. if yes jump power to the yellow? wire on the starter solenoid, does it crank? if yes check your igniton fuses. if the fuse is good check your main harness plug for corrosion. if no corrosion check your igniton switch.

 

[bigbrownbuku]

Re: mercury 50 outboard turns over only sporadically

the evil double post

 

[Silvertip]

Re: mercury 50 outboard turns over only sporadically

If there was no change in voltage when the key was turned to start, there is very likely a cable corrosion/looseness problem. Remove the battery cables (both ends of both cables) and clean them and the attachment points with a wire brush. Reattach them securely. If you use wing nuts on the battery, tighten them with a pliers. Finger tight doesn't get the job done. Now try starting the engine. If it works repeatedly, fine. If not, Now its time to try jumpering the solenoid and ignition switch. To test the ignition switch, connect the voltmeter to the small terminal on the solenoid and the other lead to ground. Turn the key to start. If 12 vis present great. If not, the switch or wiring is bad. To test the solenoid, turn the key to RUN. Using a short wire, touch one end to the BIG post on the solenoid on which the positive battery cable is connected. Touch the other end of the wire to the small post on the solenoid. There may be two small terminals on the solenoid, one is grounded to the engine block. Touch the jumper wire to the other one. If the engine now spins, the solenoid is ok. If not, the solenoid is bad.