1966 Johnson Super Seahorse 40hp?

[khmerboired]

Hey guys,

Well, i'm a little confused. Me and my father just bought a 1966 Johnson Super Seahorse engine for our boat from a friend. BUT i'm not too sure what the fuel ratio is. Does anyone know the exact ratio? I'm thinking 32:1 should work but i'd like the know exactly just to be on the safe side. Any suggestions would be a great help. Thanks!

-Steve

 

[jay_merrill]

Re: 1966 Johnson Super Seahorse 40hp?

I don't know the year for conversion to the 50:1 ratio for sure but I think it was 1964. Additionally, that motor should have needle bearings at the crank/connecting rods, so a 50:1 mix of semi-synthetic or full synthetic should be just fine.

Wait for a couple of more responses to confirm this - JB or FR will probably chime in pretty soon and they will know.

 

[samo_ott]

Re: 1966 Johnson Super Seahorse 40hp?

Yep, 50:1 after 1964.

 

[AndyT]

Re: 1966 Johnson Super Seahorse 40hp?

I've read on some forums that a 50:1 mixture is OK for the older models as well, Can I safely use 50:1 in my '63 Johnson 40?

 

[samo_ott]

Re: 1966 Johnson Super Seahorse 40hp?

It's a grey area. Officially I believe it's 50:1 but some will do it, some wont. I usually run my older ones with synthetic tcw3 and around 35:1 or 40:1 or so which is in the middle.

 

[jay_merrill]

Re: 1966 Johnson Super Seahorse 40hp?

We've discussed this one quite a bit in the forums and there are certainly differing opinions. I think most have come to the conclusion, however, that the type of bearing surface at the crankshaft and connecting rod junction is the key issue. If your motor has needle bearings in this area (which I think it does), many feel that a 50:1 mix is fine, as long as you are using an appropriately rated semi-synthetic or full synthetic, two stroke oil.

I have a pair of 1958 ERude Bigtwins that have been run on Pennzoil semi-synthetic for hundreds of hours with no problems. They are not currently on a boat because I replaced them with a 1972 Johnson 65hp motor for better fuel economy. If it weren't for $4.00 gasoline, I might be tempted to run them again just for the "kewl factor!"

 

[khmerboired]

Re: 1966 Johnson Super Seahorse 40hp?

Okay thanks! I tried it, smokes a little but runs fine. Thanks guys

 

[tashasdaddy]

Re: 1966 Johnson Super Seahorse 40hp?

50:1 is fine the change over officially was 1964.