See full version: Gas oil miture on 7.5 evinrude outboard
The only articles that I write about are ones that I personally have worked on that motor, so you may see gaps in my articles. However I have had a lot of requests for information on these older small motors, therefore this is info that I have found on OMC parts lists is as follows.
Using this code system, if the motor was sold as an Evinrude, then the first letter would have been an E instead of the J for Johnson. Then you can encounter motors made in or for other countries, which will have some added letters as mentioned later in this article.
This slotted screen is made of plastic which would be hard to remove and save after many years, plus it is expensive to replace. So using a small nail or similar tool, you should be able to carefully clean any debris from the holes clear enough to make a difference. [links]
Fuel/oil mix on all the OMC motors that have needle roller bearings (this motor included) is 50-1 of TCW-3 standard outboard oil. However I have found that since I troll much of the time, other than getting there and back, I like to use a mix of 75-1 but of a SYNTHETIC blend oil instead of the standard oil. This gives me at least the same or better motor lubrication, plus it gives me less smoke at a troll and the spark plugs last longer before fouling.
The normal number of turns out from lightly bottomed out for the low speed (idle jet) #15 is 1 1/2 turns as a start setting. Many motor like 1 1/4 turns out. more
The official OMC fuel/oil mix for most outboard motors in this year ranges has for years been 50:1. This means 50 parts of regular gasoline to 1 part of outboard motor oil. Remember that this was before unleaded gasoline or even possibly an octane rating that was listed at the pumps. Now the recommended fuel is 87 octane gasoline.
Besides, how do I mix the gas in my Evinrude outboard?
Also, what is oil mixture for 2 stroke outboard? 2-STROKE OUTBOARDS (CARBURETED) Normally your Tohatsu outboard uses a 50:1 oil/fuel mixture (500 mL of oil for every 25 liter of gas). During the break-in period you should use a 25:1 oil/fuel mixture (1000 mL of oil for every 25 liter of gas).
Divide the number of gallons by the mix ratio for the motor use. While a 5-horsepower motor is unlikely to be subjected to racing conditions, the racing mix is 25 parts gasoline to 1 part oil--a full 5-gallon container, 640 ounces, is properly mixed when you add 26 ounces of oil: 640/25=25.6, or 26 ounces. [links]
Evinrude outboard motors made since 1964 require a 50 to 1 fuel to oil mixture using 6 gallons of gas per 1 pint of oil. Motors made prior to 1964 take a 24 to 1 mixture. The most common mixture for motors made prior to 1955 was 16 to 1. more
Evinrude was founded by Ole Evinrude in Milwaukee, Wisconsin, in 1907. Evinrude filed for bankruptcy in 2000 and was bought by a Canadian company by the name of Bombardier Recreational Products. Evinrude produces two-stroke direct fuel-injected motors that vary between 25 and 300 horsepower. Carburetors were used in Evinrude engines until the late 1990s, when direct fuel-injection technology was made available.
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Please note that some Johnson and Evinrude Owners Manuals mention 100:1 mixture ratio after the motor is completely broken in, but most experts suggest against doing that. Stick with 50:1 for the 1964 and newer motors. more
However as time went by, there came about a great amount of discussion as it seemed more than a normal amount of powerheads were being rebuilt in a given time period.
Keeping it short, a rule of thumb was accepted that any engine that had a powerhead that incorporated “ALL” needle, roller, and/or ball bearings on its moving parts (crankshaft, connecting rod, wrist pin) could safely use the 50/1 mixture…… and any engine that DID NOT should use the 24/1 mixture.
Below is some additional information from our friend and frequent forum contributor Joe Reeves: [links]