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[havinfun]

I did a search on fuel mixture, got 200 hits, read them all. Seems to be a little gray about where the cut off year is for 50:1. I'm looking at a rebuilt 1977 140 HP Evinrude model 140743. The owner of the boat said he had been using 30:1 but has trouble fouling plugs. I hate to ask again, but what's the right mixture? Is there a line in the sand, use 50:1 after this date? Thanks in advance, <br />one of the poor folks that can't afford new stuff

 

[ED21]

Re: most ask question

I'm not exactly sure of the line, but you are way past it. 50:1 is the right mix.

 

[R.Johnson]

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OMC went to 50-1 in 1963, or 64 as I recall. There has been a lot of discussion on this board as to oil's. I would simply use OMC oil. I have not yet run it myself, but several members feel the oil for the Ficht's is a good way to go. I would have no reason to doubt it.

 

[Paul Moir]

Re: most ask question

I've got a '64 OEM manual for my 28hp, here's a bit from the break-in section:<br />

After 10 hours of operation, the mixture for 1964 motor [sic] should be 1 pint to 6 gallons of gasoline.<br />NOTE<br />Mixture for 1963 motors after break in period [sic?] should be the same as used during break in period - 1 quart of oil to 6 gallons of gasoline.

And I've been complaining about the use of 'English' in modern manuals! <br />Your memory is better than mine R.Johnson!

 

[havinfun]

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THANK YOU ALL, you guy's have a lot of patience with us poor folks, and I appreciate it! What a site!

 

[alcan]

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This question seems to come up quite often. Exactly where is the line between 24:1 and 50:1? Well I thought I might have a copy of the original service bulletin from OMC reguarding this. I dug and searched. I may not have exactly that copy, But I did come up with something close. Here is what it says. <br /> Evinrude Service Bulletin #628 Oct 29 1963. <br /> 50:1 FUEL RATIO FOR 1964 MODELS.<br /> BREAK-IN IMPORTANT<br /> Before the new 50:1 fuel-oil ratio is used in any 1964 Evinrude, it is extremely important that the breack-in procedure in the owners manual is followed exactly.<br /> The break-in procedure requires that all engines be operated on a 24:1 fuel-oil mix for a period of 10 hours on models 28hp. and up and 5 hours on models 3 through 18 HP.<br /> Customers should be cautioned that any deviation from these instructions may cause powerhead problems that would not be covered under warranty.<br /> The "Break-IN" procedure appearing in the 1964 Owner Manuals fro 28 throu 90 HP is as follows:<br />For the first 10 hours of operation, including break-in period, the fuel<br /> mixture ratio should be 1 part of oil to 24 parts of gasoline, <br />or 1 quart of oil for 6 gallons of gasoline.<br />DURING THE FIRST HOUR- For the first 5-10 minutes, operate<br />engine at a fast idle. Check operation of water pump frequently.<br />For remainder of first hour, do not operate engine over 3000 RPM<br />(approx.) or one-half throttle (approx.). NOTE: With easy plan-<br />ing boats, it would be desirable to bring the boar into planning<br />position with full power and then immediately reduce the throttle <br />setting to approximately 3000 RPM (one-half throttle) BE SURE<br />boat maintains planing attitude at this throttle setting.<br />DURING THE SECOND HOUR- Bring boat into planing attitude and reduce<br />Power to 4000 RPM (approx.) or three-quarters throttle (approx.)<br />while maintaining planning attitude. At intervals during the <br />second hour, apply full power for periods of one to two minutes,<br />returning throttle to original setting (4000 RPM – three-quarters<br />throttle) for a cooling period.<br />Avoid continuous full throttle operation for extended periods<br />during the next few hours. <br />The procedure appearing in Owner Manuals from 3 through 18 HP reads as follows:<br /> For the first 5 hrs of operation, including break-in period, the fuel<br /> mixture ratios should be 1 part oil to 24 parts of gasoline, or 1 quart of <br /> oil for 6 gallons of gasoline. <br /> Do not operate engine at continuous full power for the first hour of<br /> operation. After 15 minutes of slow to half throttle operation (2500 RPM<br /> approx.) we recommend a short burst of full throttle operation every five<br /> or ten minutes. Run at full throttle for about 90 seconds, then return to half <br /> throttle or less. Check operation of cooling system frequently during break-in.<br /> CAUTION- Do not start or operate motor out of water as it will result in<br /> damage to water pump, overheating, and too high RPM.<br />Some of the early Owner Manuals did not include information on the 50:1 fuel-oil ratio. <br />Engines that were packed with these manuals have a yellow tag attached to the fuel tank<br />Explaining proper use of the new ratios. Be sure all of your personnel as well as your customers are aware of these new break-in procedures.<br /> From this Service bulletin I under stand that the switch was at the beginning of the 1964 model year. If anyone wants a copy E-mail me at alcan.fixit@verizon.net

 

[Joe Reeves]

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Alcan.... Also, if memory serves me correctly, OMC came out with a bulletin many years ago which stated that all of their engines could use the 50/1 mixture, excepting the 1957 7.5hp model.<br /><br />I've searched through everything I have and cannot locate it. I can picture myself reading that bulletin but that's been quite a few years ago, and due to the age factor I've had times when I think it's possible I misread it.<br /><br />However, any OMC engine that has a full set of roller/needle bearings such as the 1958 V/4 50hp model and others can safely use that 50/1 mixture, which leads me back into that loop regarding the bulletin I speak of.<br /><br />Should you ever run across it, I'd appreciate knowing about it. Thanks......

 

[DHPMARINE]

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Good Evening Guys.<br />The only reference I know of for OMC outboards is 50:1 after breakin.25:1 is for breakin.<br />References for 1qt to 6 gallons is found on older outboards.Then we didn't have 2stroke oil.This formular was for 30W motor oil.(wich did not stay mixed very well).Only other reference was 100:1 on small HP outboards.But later OMC reversed their advice saying 100:1 was okay for operation,but not for engines that sit for a few weeks between usage(not enough lube to keep internals from damage).<br />DHP.

 

[alcan]

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Hi Joe, if and when I come across this rascal I'll be glad to shoot you a copy. Personaly I have pretty much used the fuel pump as a guide line. If the big twin 35hp had a fuel pump I run them 50:1. This means I too have run older motors on the then new mix with out problems (after breakin). All the smaller models regaurdless if they had the up graged fuel system I run 24:1.<br /> DHP I am getting to the point that I also don't remember as well as I think I should. Things like wether or not I have a certain S.B.I do remember a few things about the fifties though. This country just finish a war. Started several more. We had atom bombs, T.V. was the rage (black& white of course. We didn't have cell phones, micro waves and computers that the general public could use. But we did have 2-stroke motors and the oil to go with them. The brand OMC recomended was Mobile outboard oil.

 

[R.Johnson]

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Alcan: I was running outboards in the 50's The oil was Mobile outboard. 1 quart to 6 gal. of gas. Ran a 10 HP Wizard till I got the money for a 1954 25 HP Evinrude. This was on a 12.5 ft. Dunphy. Time flies!