Merc KE4 gas/oil ratio question

[DAN UMBARGER]

I’m getting ready to run for the first time my Merc KE4. What is the general consensus on oil ratio. The only thing I have been able to come up with is 3/4 pint to a gallon.. seems pretty heavy to me.  Also does anyone know the initial carb settings for this motor?

[dave-bernard]

25-1 was ratio back then

high speed 1 turn out

low start about the same.

[DAN UMBARGER]

Thanks Dave, once I get this thing running well I’ll be getting back to you on what I may need…did buy a recoil handle already and found a choke knob locally.

[dave-bernard]

10-4

[DAN UMBARGER]

Put the motor in the test tank and after a little fiddling got it running, pumps good water and idles great with the low speed set at 1/2 turn and high speed at 1 1/4 (temporarily). I decided to run the oil ratio a little richer @ 18:1 for the first startup. The only problem I have is I have a water leak and it appears to be coming from in between the cylinders towards the block. In the diagrams I have been able to find it looks like there is a gasket between the block and both water jackets. Are these available or do I need to make them? Other than the water leak this motor actually runs very nicely….I think it’s a keeper!! I think I might just finish restoring/painting it. To date I had to clean/set the points,rebuild the carb with a new float and gasket set,new impeller,repair the recoil,new recoil handle, a choke knob and new cornhead grease in the g/case.

[dave-bernard]

run it for a while the leak may go away when the gasket swells.

[baron0418]

The original ratio was 12/1 or 3/4 pint per gallon. the mark 7 and other mercurys from about 1954 used 20/1 or 3/8 pint per gallon. Just read it off the motors themselves and you will see I am correct. Example Ke-4 serial # 439752   3/4 pint per gallon.   Mark 7 serial # 559557  3/8 pint aeromarine 2 cycle oil OR 1/2 pint 30wt non detergent motor oil. That is just plain fact. But by all means say whatever you want.

• This reply was modified 3 years, 8 months ago by baron0418.

[dave-bernard]

12-1 was for racing only. double that of the service motors. when merc came out with 50-1 oil ALL Mercs could us it. they all had needle and roller bearings NO bushings like OMC’s. Fact not fiction.

[DAN UMBARGER]

dave-bernard wrote:

run it for a while the leak may go away when the gasket swells.

Dave, ran the motor again tonite and the leak was gone for about 5 minutes then it came back ever so lightly…will try it again tomorrow and see what happens…at this point I think I’ll leave it alone because the leak is so minute it wouldn’t hurt a thing if it did leak 1 drop every 15 to 20 seconds if it’s even that much. Motor seems to run great!

[dave-bernard]

Yes, it is not a head gasket. just a water jacket. those bolts can break when removing them.

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