Re: 1966 Evinrude 18hp… cough sputter cough!

[optsyeagle]

Usually when you get a low power motor that suddenly pops into action for you and then bogs again, you are experiencing one cylinder intermittently cutting in and out. If it is not working at all, I would do a cylinder drop test to find out which one is not working. To do so, simply fire up the motor, let it warm up, bring it to a fast idle and with a pair of insulated pliers pull one spark plug boot at a time. If the motor dies, then you now know the other cylinder was never firing or is very weak.

If I had your issues, I would want to do an external spark test to verify that each cylinders ignition can jump a minimum of a 3/8" gap and I would want to verify that the compression on both cylinders was even within 5 psi.

Now you talk about backfiring. When you changed the coils is there a chance that you mixed up the wires going to the two spark plugs. I would think that if you did, you would not get either cylinder to run well but you might get one or both to want to backfire. Since it is backfiring, you could check that.

When setting the points, bring the point rub bar to where the flywheel key is to set them. The word TOP is just to indicate that if the cam comes off it cannot go back on either way. It must go on with the word TOP facing up. That is all that word is for.

I am not sure why the packing nut would prevent you from turning in the slow speed needle unless it is too tight. The packing nut should be loose enough to allow you to turn it either way but snug enough to ensure it does not turn on its own.