1960 vs 1962 75 hp V4 Evinrude starlight fuel mix ratio

[tbaz]

The service manuals states the fuel mix ratio is 24:1 for 1960 and 50:1 for 1962. What changed between the years

The reason I am asking is that I want to run a higher ratio in my 1960 but not sure of the mechanical reason for the recommendation differences.

The motor starts right up, idles at 800 rpm, plugs are a nice light brown, compression is 110 on cylinders but when on the slow jets she smokes so bad it is hard to be in the boat.

I also noticed when comparing the two that the 1960 has adjustable main jets where the 1962 is a fixed main.

It seems that even these motors look very similar there are some big differences in mechanics that need to be considered

 

[boobie]

Re: 1960 vs 1962 75 hp V4 Evinrude starlight fuel mix ratio

IMHO, on a mtr that old I'd run 24:1 mix. It may smoke a little and maybe foul a spark plug or two but you know it's getting plenty of lube. The manuals may be wrong. If it smokes at idle what's the temp of the mtr. Is it running to cool ??

 

[tbaz]

Re: 1960 vs 1962 75 hp V4 Evinrude starlight fuel mix ratio

The motor has a thermostat. When closed the water is cycled through the cooling circuit when open water comes out of the tell tale exhaust port. That is happening so I am assuming the thermostat is correct and opening at the right temp. Generally it takes 1 to 2 minutes to open and considering the AZ water temp that is probably correct.

Good suggestion thank you for the response

Tim

 

[Chris1956]

Re: 1960 vs 1962 75 hp V4 Evinrude starlight fuel mix ratio

The reason the fuel mix was changed to 50::1 in '62 (for that V4 motor) was that that motor had been converted to all roller and needle bearings, from simple Sleeve (bushing-type) bearings.

I personally think that the '60 motor is mostly the same as the '62 motor, and it has all roller and needle bearings. However. I do not have first hand knowledge, so I cannot recommend that change.

Joe Reeves is our expert on those motors and he could tell you exactly what fuel mix to run. He had a family medical issue, and have not seen him back ont he forum recently.

 

[yorab]

Re: 1960 vs 1962 75 hp V4 Evinrude starlight fuel mix ratio

You could go to marineengine.com and look at the parts breakdown of those two motors. Chances are that the critical parts such as bearings are identical. Therefore, if there are no differences in mechanical parts, then it seems that there should be no reason to have different gas/oil ratios. I have a 1963 Starflite and a parts motor that is a 1961. They have identical parts, though there were some aesthetic changes between those years. I know what I would do, but the decision is yours if you find that the parts are identical. However, boobie does bring up a good point that peace-of-mind is also good when it comes to getting enough lube to the critical parts in that old motor. It's just that peace-of-mind doesn't help much when your boat is so smoky that you can't use it. Let us know what you decide to do.