Re: evinrude 150 hp ficht wont start HELP
Have you tested the voltage across the battery, 12.65 volts? Also have it load tested as Tash stated. Clean all those connections until they shine, you cant just look at them and assume they are ok. Inspect the entire cable, especially where the cable enters the terminal, for bulging of insulation which is a sign of internal corrosion. Replace the cables or cut the ends off and install new ones as required. DO not overlook any of the battery/starter/solenoid cables and/or connections. Including ground.
If it now works, great, if not, use a short jumper wire to short the small terminal on the solenoid to the large terminal on the solenoid (the one that has the POSITIVE battery cable connected to it). Be prepared for a spark. You are essentially doing the same thing that the ignition key does in the START position. If the engine spins fine every time, you either fixed the problem, or if not, the problem is in the harness between the engine and ignition switch.
Disconnect and inspect the large harness plug in the engine compartment. Clean it as best you can and reconnect. Now use the ignition switch to try and start the engine. If it works every time the connector was the culprit. If not, you now need a voltmeter.
Put the POS voltmeter lead on the small terminal on the solenoid. The NEG lead goes to ground. Have someone turn the ignition key to START. If you don't see 12V troubleshoot the harness between the engine and control box. If 12V is present every time, the switch is good.
At this point, connect a single jumper cable between the POS batter terminal and directly to the large terminal on the starter. If the starter spins each time you do that, the solenoid is likely the culprit but there is one more test.
Connect another jumper cable to the NEG battery terminal and a good ground (bare bolt head or bracket) on the engine. Now do the same test you did previously. If the starter now goes ok, you still have a negative battery cable problem or the solenoid is bad. If it still doesn't work right, you have a bad starter.
Alternatively, get yourself a multimeter and measure the voltage at the starter (+) terminal while somebody turns the key over to "start" - if you get within half a volt or so of the battery voltage, the starter is faulty. Try turning the bendix a 1/4 turn, if it now fires, the brushes in the starter could be at fault.
Bad voltage at starter (with clean tight connections), measure the voltage at the solenoid small terminal with the yellow/red wire with the key turned over to "start" you should read within a half-volt of battery voltage, otherwise you have a wiring fault beween the keyswitch & solenoid. Good voltage at solenoid but bad voltage at starter means faulty solenoid.
