Can't start my 175 hp mercruiser outboard. Any suggestions?

Question

I just bought a 93 175hp mercruiser checked the compression all at 125psi. It was running for a week and now it won't start at all. New fuel filter, ball gets hard, seems to be getting gas. Idle was rough and low but it was okay for a week. Kill switch has been disconnected, gas is clean. Any suggestions with this problem?

Answer 1

Check all grounds if not that then have a mech= look at it>Sounds electrical>

Answer 2

Is this a mercruiser or an outboard?

Was the idle low and rough or was it okay?

Explain what you mean by "kill switch as been disconnected"?

Are the plugs wet or dry after cranking?

Have you checked all cylinders for spark?

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"Checking the plugs" is not the same as checking for spark.

You need to find out if the ignition is generating enough electricity to make 'em spark.

Remove a plug, reattach it to the boot, hold it against the engine block and look for a sharp blue spark while somebody turns the engine over with the key.  Repeat for all six.

Use an insulated or plastic tool to avoid getting shocked.  Autozone sells a plastic "plug boot tool"  for a couple bucks.

If the plugs are dry after cranking, it indicates fuel is not reaching the cylinders.

You need at least 250 cranking RPMs to generate enough of a spark for the engine to start.  If you've done a lot of cranking, battery might need recharging.

How old is the fuel?  Check the tank for water and/or debris.

You have good compression...if you got spark on all cylinders, & fresh fuel, a carb rebuild is in order.