Topic: Fuel mixture Evinrude 18 HP Fastwin 1960 – Antique Outboard Motor Club,Inc

This topic has 7 replies, 5 voices, and was last updated 1 year, 5 months ago by salnaes.

Viewing 8 posts - 1 through 8 (of 8 total)

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November 24, 2022 at 11:13 am #269319
salnaes
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International Member
I’m finished restoring my Evinrude 18 HP 1960 and ready to start the engine in a test tank for the first time. There are new pistons and rings, honed cylinders, all new gaskets, seals, bolts and much more. All ignition parts (coils, points, condensers, spark plugs, leads and so forth) are new. Carburetor is serviced with new float, needle, gaskets and all parts that came with the overhaul kit. Filter bowl is serviced with new filter and gasket. New fuel pump is installed. All fuel lines are new, on tank and engine. I can’t think of anything that’s not been serviced.

I have been reading posts here on this forum to find the correct fuel mixture to use now. I think that 24:1 mixture is what I have to use. Right? I guess that’s approximately 4% of oil in the fuel mixture. Am I right? So if I have 10 liters of fuel, then I have to add 0,4 deciliters of oil? (I apologize for using European units, since I’m Norwegian)

A local marine mechanics here at my place think that’s way too much oil since oil in 2022 is much better than oil was back in the days, he says. He says that 1% is enough!

I wanna listen to experienced people here at aomci, and follow the best advice. I recon you know this better, so I ask for help.
November 24, 2022 at 11:46 am #269320
crosbyman
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Canada Member - 2 Years
I believe 1960’s will run on 50/1 but to keep it simple mix 1L quality twc3 in 25 L fuel for a 25/1 mix and no harm will come to your oldy 🙂

any smoke is good for the bugs anyway

you did do the impleller and GC oil….

Joining AOMCI has priviledges 🙂
- This reply was modified 1 year, 5 months ago by crosbyman.
- This reply was modified 1 year, 5 months ago by crosbyman.
November 24, 2022 at 12:06 pm #269323
fleetwin
Participant
US Member - 2 Years
While today’s oils have surely improved, I would recommend staying with the original 24:1 mixture, especially during the break in. These engines, when in good tune, hardly smoke at all, even at 16:1. Stick with the original recommendation, 24:1.
November 24, 2022 at 12:23 pm #269324
billw
Participant
US Member - 2 Years
I run 24:1 in my 18s all the time. Not too much smoke and added assurance against any damage. These engines seems to be often found with the power heads frozen from corrosion in the cylinders and/or bearings. In my mind, 24:1 will help combat that, a little bit.

Long live American manufacturing!
November 24, 2022 at 12:57 pm #269325
salnaes
Participant
International Member
Thanks all for answering. I’m a little confused about the notation 24:1. Could you tell me what it means? Does it mean 24 parts gasoline and 1 part oil?

Yes, I did the impeller and gear case too. Everything is restored.
November 24, 2022 at 1:17 pm #269328
crosbyman
Participant
Canada Member - 2 Years
one Liter (1000 cc) of twc3 oil in one tank of 25 Ltrs fuel…simple

if you want 24/1 take 25 L (25000cc devide by 24) you get 1041.666 cc’s

in conclusion just mix 1 ltr oil in 25 ltr fuel ====> 25/1 the engine won’t know the difference between 24/1 or 25/1

Joining AOMCI has priviledges 🙂
November 24, 2022 at 1:27 pm #269331
Steve D
Participant
Yes that’s what it means. 24:1 = 128 oz. gas (1 gal) to 5.33 oz. oil. Here’s a handy chart.
November 24, 2022 at 3:40 pm #269338
salnaes
Participant
International Member
Wow! Thank you all for helping me on this issue. I will use 24:1 with twc3 oil and perform break-in procedures in a test tank.

Break-in as follows:
1. Operate at 1/2 throttle for 2 hours (2500 – 3500 rpm)
2. Operate at different speed except full throttle the next 8 hours.
As soon as the engine starts I will check for water coming out with the exhaust. If not, I will stop the engine and check why it’s not cooling.

I will also have to adjust low speed and high speed on the carburetor, but the needles are already set to initial settings: 3/4 turn out on high speed and 1-1/2 turn out on low speed. Hope that’s right.

Synchronization is already performed according to tune-up specs (center of the roller on cam mark when throttle shaft starts moving). Manual Seloc.

Spark plugs gaps are set to 0.30” and I used the special timing tool and multimeter to set the points break. I don’t have a Buzz box, so I had to disconnect the leads from coil, condenser and stop-button to have the buzzer on the multimeter signal at the correct position. I’m pretty sure I didn’t move the point gap when fastening the leads after setting the break point. Ignition leads, spark plug caps and spark plugs are brand new. So I’m really exited now. Hope everything works.
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