Need info for 1961 5.5 HP Johnson CD-18

andreipou

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Hello, I just got this motor in very nice condition, but it does need good tune up.
This is first OMC I got older then 1967.
All manuals I have start with 1965.
I did some web searching, but found details that differ.
Can anyone confirm if the info I have is correct?

1. Spark plug : Champ J4J or J6C (gap .035'', really? usually it is .030'')
another version NGK B6S (gap .030'')
2. Idle speed needle in carb - 1 & 1/4 turn out
3. High speed needle - 1/2 turn out
4. Fuel mix : 22:1 (really? first time see such oily mix)
5. Timing adjustment.
Mark on the cam has to align against left side of the cam follower roller when carb throttle just starts to open (see pic).


Thank you .
 

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Crosbyman

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a real good book to work on your CD is

$100 bucks is nuts buy used or shop around
here are afew links for you

your motor likly needs new coils condensers a good points clean-up oil on the oil wick new plug wires and boots

great engine ! check compression before spending $$$ on your new oldy.
look for compression above 85-90 hopefully.
check the GC oil for water !! some just replace the oil mid and end of season otherwise a GC reseal is needed

check thermostat changing the impeller requires the head to be pulled ... not so hard as it seems. when pulling the head try not to break the base gasket ...just reuse it.
new ones available


start with the simple stuff. lots of utubes to help you

a 1961 may be ok on 50/1 but I run them 25/1
 
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racerone

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The original mix was 24:1 on those.------But 1961 was the first year for needle bearings on big end of the rods.----So internally there is no difference with a 1965 model ( now rated at 6 HP ) that ran on 50:1 mix.----Another lively oil debate.
 

F_R

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Pay attention to what the video says about the carbon seal on the driveshaft. If the seal doesn't do its job, water leaks into the powerhead. Slow leak that won't be noticed. Until the motor throws a rod. People then look at the damage and say it tossed the rod because of lack of oil. Nah, it was the water, not the oil. Always install a new 303355 gasket and 303347 o-ring on the seal.
 

andreipou

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Compression is 105\110.
Took flywheel off, everything looks perfect.
One coil was definitely replaced, points look new.
I made sure point gap is .02''.
Put two new plugs Champ J4C with .035'' gap.
(CAN ANYONE CONFIRM OEM RECOMMENDED PLUGS AND GAP FOR THIS MOTOR?)
Got strong blue sparks.
Disassembled and cleaned carb (it was very clean).
Replaced fuel lines.
Motor starts with first pull and runs great after all adjustments.
I ran it for about 1 hour.
The temperature of PH did not go over 125F, spray was good.
It runs a little "smoky", but could be because of issues I describe below or "oily" mix (I never ran 22:1 mix before).
Overall, this motor looks great\clean for its age, probably was not used much or taken very good care of. Definitely freshwater motor.

Now possible "bad" things:

1. When tried to drain LU, got "stuff" I never seen before (I saw oil from leaky units before). White thick mass that looks like sour cream and almost did not want to run out.
I flushed LU with kerosine twice to liquify it.
Filled with new oil, run 15 mins in gear, replaced oil again.
Will see in a few days how it looks.
Need to get my pressure tester for LU back from a friend...

2. F_R , what you said about water in PH worries me, because when I tried to check compression, I noticed liquid going from cylinders to manometer. It did not smell, so I guessed it was water. Motor did not have any sign of being submerged and I thought that probably someone tried to run it from tank that had some water in it, and it got pulled to cylinders somehow.
To deal with it: with spark plugs , carb, fuel pump and flywheel removed I blew cyls with air. Then put flywheel nut on and used drill with socket to rotate shaft and spray WD-40 into cyls and reed valves. Then compressed air again, then WD-40, air, WD-40 again and again.
At the end I put fogging oil while rotating shaft.
After that I did all the tune up things above and got it running.
So, how can I check if it has problem you described or else?
 

F_R

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You wouldn't get that much water from the carbon seal. Gotta be a serious leak somewhere. But you said it runs great. I dunno where it came from.

Your spark plugs type and gap are close enough. Not an issue.

Somebody may have put lubriplate grease in lower unit. Recheck after running a few hours.
 

racerone

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If it still has the original head gasket you might consider removing it,------The new gaskets are improved.---Sierra is the best deal.----Inspect thermostat as they are often stuck open or missing.
 

andreipou

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So far motor works well.
The only complain is it smokes more than usual.
I tried to run it on 50:1 mix instead of 25:1 and it was still some smoke, but less.
What else can I do?

Also, does this motor have timing markings for strobe light?
Can not find any...

Thanks.
 

Crosbyman

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smoke... are you using quality TCW/ oil ? smoke is good for bugs at low speed :)

you can try some more fancy synthetic bio oil like XD-100 $$$ and it contains carbon guard.
but.....run it no less than 25/1 !!!

at lower rpms they may have a tendency to load up more due to the accumulation of oil/fuel in the crankcase ... more so if the purge valve or channels are blocked. At higher rpms the fuel oil mix is beter vaporized and gets burnt more properly.

cleaning out the purge system valve and channel is part of a good refurbish. see description

If you time as per the above video I don't think you will do much better with a timing light...but use the yellowed out markings in the video .
 

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racerone

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Yes there are timing marks.-----Point the timing light at the 2 vertical lines on the magneto plate.----And magically it always fires between those 2 vertical lines.
 
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