Tips on 1971 18 HP

[bob1340]

I am new here.

My son just got a free 1971 18102S 18 HP Evinrude. It has been run very little and not run at all in 20+ years. I rebuilt the bottom end/gear box as it had no oil in it and was full of water. Looks like the rear seal went out. There is a slight scoring on the front bearing/shaft, but not bad, more of a discolor than actual wear. It is all sealed up now and has a new ($$$$) rear bearing/seal. . New starter rope. New fuel pump. Carb rebuilt. New plugs. New water pump impeller. I cleaned the fuel tank and installed a new hose. I have a new thermostat on order. It fired up on the second pull. I did mix a gallon of 32-1 mix as this think has not run in a while and I wanted extra oil in it.

Here are my questions:

Is the fuel tank vented? If I let it sit it seems to build a lot of pressure in it as the sun heats it up. Should it be vented?

It seems to run fine, but should I replace the 39 year old points and condensers?

On the "lean/Rich" needle adjustment, any tips/hints?

Anything I need to pay attention to on this motor?

 

[mchin]

Re: Tips on 1971 18 HP

These motors are near bullet proof, that's a cool story. The tank does have a vent, most modern tanks have the vent on the gas cap. The vent allows the leaving gas to be replaced by air. If it were my engine, I would replace the ignition parts, but that's me. In my experience, you should be fine, but I hate the feeling of waiting for it to break down - the never knowing is killer for me. I typically run my older motors a little rich, in the getting your old engine started again sticky, there are tips on needle settings, I think the setting is 1-2 turns backed out from dead bottom. I would set the low first, let it come up to operating temp, and then set the high speed needle. I would also set the low at home and then play with the high speed on the water, find the peak and back off a 1/4 turn or so.

 

[bob1340]

Re: Tips on 1971 18 HP

These motors are near bullet proof, that's a cool story. The tank does have a vent, most modern tanks have the vent on the gas cap. The vent allows the leaving gas to be replaced by air. If it were my engine, I would replace the ignition parts, but that's me. In my experience, you should be fine, but I hate the feeling of waiting for it to break down - the never knowing is killer for me. I typically run my older motors a little rich, in the getting your old engine started again sticky, there are tips on needle settings, I think the setting is 1-2 turns backed out from dead bottom. I would set the low first, let it come up to operating temp, and then set the high speed needle. I would also set the low at home and then play with the high speed on the water, find the peak and back off a 1/4 turn or so.

I will figure out the vent. I guess the gas cap had a tiny hole at one time, but no longer vents now.

I did order new points, condensers and coils.
From what I can see the carb only has one adjustment and that is the low speed needle. The manual says adjust it out 1 turn then play with it once running. The needle is linked to a knob on the front of the motor. I am guessing the knob should read LEAN once the adjustments are done at sea level and then it can be enriched as I go to higher altitudes? The service manual really does not say.