Have a 17yr old Johnson 30 hp outboard. What is the correct gas/oil mixture for this engine?

Question

Have a 17yr old Johnson 30 hp outboard. What is the correct gas/oil mixture for this engine?

Answer 1

I believe that it is new enough so that it should run 50 to 1 no problem. But, if you're questioning, go 40 to 1.

Answer 2

Run 40 to 1.

Answer 3

50:1. Only really old motors, which yours is not when it comes to outboards, specified 30 or 40:1. That was because 2 cycle oil technology was not as advanced as today. Any modern 2 cycle oil can be run at 50:1 in your motor.

Answer 4

50 to 1 16 oz of tcw3 to a gallon of gas

Answer 5

Well, 50:1 is nominal.  I'd suggest running 40:1 due to the age of the motor's seals, and the bearings will last longer

Answer 6

50:1

Answer 7

pint to six gallons

Answer 8

I have a boat with the same engine and it was origionally running a 50:1 unleaded to tcw3 (2stroke marine oil). However one of the pistons ceised, then i ran it on 30:1 and never had any problems since. Too much oil is better than to little. I beleive 50:1 is recomended, but in such an old engine, i would rather be on the safe side.....

Answer 9

50:1 ratio

Answer 10

50:1 is the correct ratio. the old saying to much oil is better than not enough is false!! I wish people who dont understand the true workings of a modern engine would check their facts. the omc engine you refer to has an L shaped or keystone style piston ring for the top ring(as do most modern 2 strokes). running excessive oil causes carbon deposits to build up under the rings. remember carbon is the strongest material known to man. the carbon pushes the ring(s) out against the cyl wall and causes scoringand ring breakage. this is a common problem in high hour engines and when people use too much oil or poor quality oil. remember the debate about brand name oils? the real problem is not that they dont lubricate well enough, its that poor quality (cheap) oil doesnt have a good additive package for clean combustion!! I have worked on all brands of engines for 25 plus years in recreation boating and fleet operations (you see alot of data when you run 50 -70 engines in a relatively controlled system) this particular debate caused a riff between me and the owner of a fleet operation in the mid 80's. we ran our engines on brand x oil and after a season looked at our carbon problems(as well as sparkplug use and runability problems). the next year we ran branded oil(omc) and after the initial carbon fouling left, our service costs dropped in half. I even had a three cyl build a carbon deposit completely to the top cyl causing the engine to finally snuff itself out!! with cheap oil. the owner was very humbled and pleased. In the recreation side of the shop most lubrication and carbon problems were also from cheap oil/ too much oil. Just because some people get by burning more oil doesnt mean it wont cause problems. most engines with scored cyls are not from oilgas mix ratio!! (engines dont run long without oil) a severly scored piston/cyl assy means the piston ran quite a while to do the damage.please follow all manufactures recomendations when mixing/ using oil. for omc engines 1955 and newer use 50:1 (omc came out with a service bullitin in the late 70s on older motors and 50:1 as long as you use good oil). ps most of the newer omc engines mid 87 and newer can run on 100:1 (silver plated needle bearings) but that is another question ,besides remember that the largest benifit to oil injection vs premix (besides conveinience) is the ability to add or subtract oil  as needed. this results in better performance , longevity ,engine runability, cost savings, and environmental concerns   p.s.s. to the person who scored one of his pistons if the oil ratio was weak enough to score one cyl it would have affected all cyls on the engine(usually on a multi cyl engine one cyl failure is due to lack of fuel) lean condition

Answer 11

I agree that modern out board oils at 50:1 should be good, Make sure there is plenty of water coming out from the cooloing system. An old engine may have blockage in the water jacket or water pump impellar worn, This could cause an engine to seize/