Mercury 90 hp start issue

[fbaloy]

I have a Merc 90hp direct inject and when I turn the key to start it blows the fuse every time. If I bypass and just turn the key to on it works fine. Any ideas as to why? I suspect a short in the switch. Help!!!

 

[GA_Boater]

Re: Mercury 90 hp start issue

What happens if you remove the bypass after starting?

 

[fbaloy]

Re: Mercury 90 hp start issue

What happens if you remove the bypass after starting?

Instead of using the ignition start I just started with a hot lead and touched the two wires. Used the key to kill the engine. It is when I use the key all the way over that it blows the fuse back by the motor.

 

[Texasmark]

Re: Mercury 90 hp start issue

Engine start wire should be yellow with red stripe.....is on my 90 anyway. That wire supplies 12v to energize the starting solenoid. 12v is supplied through the ignition switch in the start position from the red 12v wire connected to the switch from the fuse. Since you know that the starting solenoid and wiring harness wiring function properly, my thought is that you have a short inside your ignition switch. It happens, especially on older well used, possibly water infiltrated switches.

Mark

 

[quicktach]

Re: Mercury 90 hp start issue

Done any continuity test yet ? Is the correct size fuse in the starting circuit ? When you jump started the motor, did the starting motor work OK? All connections to it clean and tight ?

 

[CharlieB]

Re: Mercury 90 hp start issue

Ditto the suspect ignition switch.

Disconnect the battery and unplug the starter wire at the starter relay.

Rig an Ohm meter near the switch, do two tests, red to ground while holding the switch in the start position, then again the starter wire (yellow w/red stripe to ground)) You may see continuity with either or both test which would cast serious concern about the ignition switcih.

 

[JP-07]

Hi guys,
I'm new to this thread n I'm a new boat owner. I have used a Mercury 90hp pontoon n have problem getting it to start. It crank n crank but won't start. I'm afraid of over pumping the bulb n flood the engine. Your help will be greatly appreciated.