1995 40 hp mercury will not run

[sambrigman]

I just purchased this motor, the first mercury for me and I have no idea where to start. It will start and hit a couple of times then go dead. so it runs a second and goes dead immediately. Any ideas or suggestion greatly appreciated. Thanks guys

 

[tpenfield]

Since it tries to start it probably has spark. The fact that it does not stay running would indicate that the fuel system is probably gunked up.

 

[roscoe]

Spark test and compression test before anything else.

 

[sambrigman]

spark tested ok good compression, and carbs were spotless, looks like someone recently cleaned trying to fix the problem. could it electrical something to test? thanks

 

[roscoe]

If it has compression and spark, it has to be fuel, or timing - typically timing doesn't change, unless the flywheel key has sheared.

Is fuel getting to carb?
Is fuel getting to cylinder?
Are the plugs wet with fuel?

If no fuel getting to cylinders, try putting some fuel in a small spray bottle and spraying it into carb .

If all else fails, remove flywheel and check the key. When re-installing, make sure you torque nut properly or you will shear the key.

 

[sambrigman]

will do thanks