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1954 johnson qd15 10 hp 24-1 or 16-1 fuel ratio?

D

dkonrai

Regular Contributor
finally got my 10 hp running, do i run
16-1
24-1
50-1
i am confused. manual says to use 24-1 and use 30 wt oil. with todays tc3 can i go as lean as 50-1? or stick to 24-1. or then again have heard or read that some go 16-1. current mix is 16-1 by the po. seems to run pretty good at 16-1
thoughts?
dino
 
I would not go any leaner than 32:1 with today's TCW-3 oils. More oil is better than not enough. It may smoke a little more but what the heck. I associate 2 cycle oil smoke with good times. Do not go 50:1, you'll trash the motor.
 
Originally, way back then.... outboard oil was more or less simply 30w oil. Now, with todays high quality outboard oil, you can safely use the 24/1 fuel/oil mixture (1qt of 50/1 oil to 6gal gasoline). However, as "SuperT" above states... DO NOT attempt to use the 50/1 mixture on that engine.
 
As a follow up, add some Seafoam to the first 4-5 tanks of gas, that will help clean up the inside of the motor. I myself use Seafoam in every tank of gas. If you can, stay away from the blended gas w/ethanol whenever possible.
 
SuperT said:
As a follow up, add some Seafoam to the first 4-5 tanks of gas, that will help clean up the inside of the motor. I myself use Seafoam in every tank of gas. If you can, stay away from the blended gas w/ethanol whenever possible.
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i live in california = ethanol :(
 
I would stay with 24 to 1. These older motor used some bushings on rotating parts not all needle bearing like todays engine. Always use a quality TWC oil markited by either Johnson, Evenrude or Merc with no additional additives.
 
mobibs said:
I would stay with 24 to 1. These older motor used some bushings on rotating parts not all needle bearing like todays engine. Always use a quality TWC oil markited by either Johnson, Evenrude or Merc with no additional additives.
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when you say, no additional additives, i always put in marine stabil when i fill up the tanks along with the oil. so no additives? why? not to badger but i am always open for suggestions.
dino
 
dkonrai said:
when you say, no additional additives, i always put in marine stabil when i fill up the tanks along with the oil. so no additives? why? not to badger but i am always open for suggestions.
dino
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Correct I do not recomend any aftermarket additives, The Manufacturer Approved/Marketed/Tested additives are OK to use only in amounts directed. The aftermarket chemical industry is not tested in this way and when tested can/may cause damage to engine or be of no advantage to running quality of engine. When the goverment changes the fuel formula engines/additives are retested.

Have seen some real issues that I will not mention here caused by some additives in latest fuel mixes.
 
dkonrai said:
finally got my 10 hp running, do i run
16-1
24-1
50-1
i am confused. manual says to use 24-1 and use 30 wt oil. with todays tc3 can i go as lean as 50-1? or stick to 24-1. or then again have heard or read that some go 16-1. current mix is 16-1 by the po. seems to run pretty good at 16-1
thoughts?
dino
Click to expand...

Even the Operating instructions are contradictory... see attached photo.
It specifies two ratio's. 16:1 and 20:1. If I cannot get any other specific reference data, I am going to split the difference and use 18:1...
This is copied directly from the OPERATING INSTRUCTIONS Johnson Sea-Horse 10 (model QD) manual.
18:1 mix would be 7oz oil to 1 gallon gasoline.


1708912454852.jpeg
1708913177443.png
 
That information was written back when that engine was new. It's ancient history now with the advancement of 2 stroke oils.
I would say 32:1 is good but smarter people then me will chime in.
 
The 1954 model did not have needle bearings on the wrist pin.-----Unless a wise man installed 1961 / 62 / 63 pistons and rods.----So run with 24:1 on that motor.
 
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