1964 5.5 johnson

[frank27]

is this motor 24.1 0r 50.1 just want to make sure

 

[kfa4303]

Re: 1964 5.5 johnson

It mostly depends on whether or not the motor uses needle bearings. I believe your motor does use needle bearings in which case you can use 50:1, if not 24:1 is best. However, I run 24:1 in my 60's era OMC without issue. I like to err on the side of caution, and give these old 2-strokes plenty of oil. Plus, you can cut it with regular gas in a pinch and still be within a safe mix. You may want to go with a leaner mix if you're going to troll a lot, but I've never had a problem with 24:1.

 

[JB]

Re: 1964 5.5 johnson

It was 1964 that OMC said that 1964 and later omc outboards should all use 50:1 and all before 1964 use 24:1. (1964 Johnson Service Manual).

We think that was an error because some models (JW and JH 3HP) still used sleeve bearings up into about 1970. Your engine (CD-21) used frictionless (ball and needle) bearings so it qualified for 50:1.

Many outboard experts, however, recommend 24:1 in the CD series until it became 6HP. in the mid 60s.

There has been a lot of controversy lately about those recommendations.

There is no risk of damage if you use 24:1, even though it theoretically could use 50:1.

 

[frank27]

Re: 1964 5.5 johnson

i will be doing trolling so woukld 32.1 or 40.1 be better then 50.1

 

[HighTrim]

Re: 1964 5.5 johnson

I will throw in my 2 cents. Not worth much, wont even buy you a coffee.

Heavy trolling or not, I would use 24:1. People are worried about fouling plugs I imagine, but with the quality of todays oils, plug fouling is not an issue as it once was back in the day. I cannot even remember the last time I fouled a plug?? I use BRP XD oil though. It barely smokes and burns clean. If you are going to keep this motor why not keep her healthy. There are so many burned up powerheads from guys running lean mixes. This is a guess on my part but has some backbone Id say.

One of the reasons I prefer to buy motors with old crusty coils and original J6J or J4J plugs in them. I know that they were likely run on a proper mixture before the outboard companies were politically forced to go 50:1 (even worse later 100:1!) and are still healthy. Again, another guess on my part, but makes the story that much more interesting.

 

[1946Zephyr]

Re: 1964 5.5 johnson

Yea, the '61 and later 5.5's went to needle bearings, but on the rods only. The crank journals were sleeve bearing still. I would go 24:1 on it, myself. If you want to lessen the chance of fouling, set your plug gap at .040.

 

[tx1961whaler]

Re: 1964 5.5 johnson

I know that they were likely run on a proper mixture before the outboard companies were politically forced to go 50:1 (even worse later 100:1!) and are still healthy. Again, another guess on my part, but makes the story that much more interesting.

Good story, but I doubt that anybody forced anyone to go to 50:1 back in 1964.....
I agree with the 24:1-ish mix for the 5.5hp and 6hp's. They really didn't become a fully jeweled motor until they morphed into the 7.5hp in 1980, when the top crank got needle bearings, the bottom crank got ball bearings, and the wrist pins finally got their needle bearings.
All they had before that were the rod bearings.

 

[1946Zephyr]

Re: 1964 5.5 johnson

Well, I agree with HighTrim. There was some pretty strong political reasons why manufacturers were creating motors to run on less oil. It wasn't to save us money on oil. After all, oil is the cheapest thing you'll put in an egine. Some of the same people want Ford to build an F-350 to get 30 miles to the gallon. LOL