Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

x_david_x · Apr 30, 2012

Hello,

I am preparing to do a compression test on my 2003 Mercury 90 HP ELPTO 2-stroke motor. I'd like to remove the risk of ungrounded plug boots sparking or some sort of feedback to the coils or some other component getting fried. I looked for a kill switch to disable the ignition, but I can't locate it.

Does anyone have a picture or description of what I'm looking for?

Here is a picture of the starboard side of the motor.

Thanks,
David

Don S · Apr 30, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

The kill switch is that safety lanyard you hook to your belt. Usually on the control box or the dash. Depends on how your boat was setup.

x_david_x · Apr 30, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Don,

Thanks for the quick reply.

I'm probably misusing the term. Is there something I can unplug or switch off in the motor to disable electricity to the coils, but still turn over the engine with the key?

Thanks,
David

1nebel0 · May 1, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

the switch on the control box is your kill switch..put it down and that kills spark....

x_david_x · May 1, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

I do not have a kill switch on the control. I have forward/neutral/reverse, tilt up/down and off/run/start.

I would like to prevent spark from getting to the coils, but still be able to turn over the motor to build pressure for a compression test.

aussieflash · May 1, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Just ground all plugs and wires to block.

x_david_x · May 1, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Thanks for the feedback Aussie.

I can certainly ground to the block, but I'm trying to find out if there is a different way with this motor, to avoid going through the grounding work.

Thanks,
David

x_david_x · May 1, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Is this fuse between the starter and the coils? (red arrows in picture) If so, would I get my intended outcome if I unplugged the fuse? Would it still turn over, but not transform the 12 volts to thousands of volts in the coils?

Thanks,
David

x_david_x · May 2, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Well, the fuse in the previous picture didn't work. I removed it, which also stopped the engine from turning over.

I decided to punt. I made a grounding harness, plugged in each spark plug boot to the harness, jumpered the harness to the block and did the compression test. Here's the harness:

Gauge used for the compression test (Equus Innova 3615):

Results:

Cold test:

128 psi, 128 psi, 127 psi

Hot test (after running engine for 10 minutes):

125 psi, 125 psi, 125 psi

aussieflash · May 3, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

Blood pressure looks great.Now stop gloating and go boating....(that rhymes pretty good).

x_david_x · May 3, 2012

Re: Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

aussieflash said:
Blood pressure looks great.Now stop gloating and go boating....(that rhymes pretty good).

Not gloating, just posting in case anyone else wants to get an idea of compression range for the motor.

I'm selling the motor, which is why I wanted to get the compression checked. I'm currently planning to upgrade to a 135 HP Mercury Optimax.

Where is the kill switch on 2003 Mercury 90 HP ELPTO 2-stroke?

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