1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

[mobydick]

I have searched the forum and found some post that have different opinions about the fuel/ oil ratio for this engine. I was hoping someone may have the definitive answer. I know there have been post about this before so I apologize for posting it again.

The sticker on the motor says mix 1 to 24 S.A.E 30 motor with gasoline. I have read that this is not required with modern two cycle oil. I have also read that this year of engine does not have roller bearings so it needs a richer mixture then the more modern 1:50.

1. Does anyone have extensive experience (2 or more years) running this engine at 1:50?
2. What types/ brands of 2 cycle oil do you recommend?

I have been using a generic 2 cycle oil from the auto parts store at 1:24 and it seems to work OK but is smokey and will foul the plugs eventually. I am hoping to avoid plug fouling as much as possible and have the engine perform at its maximum power capability.

Thanks

 

[HighTrim]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

I run many Big Twins. I run all mine at 24:1 though. Your motor will thank you.

There are many good brands of oil that smoke less and wont foul the plugs. My personal favourite is the XD brand of oil from OMC/BRP. It is not cheap though. Another good reasonable premium oil is Penzoil Synthetic Marine.

I have read on here that alot of guys run the Walmart brand of oil with good success, but have never tried it myself.

 

[F_R]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

Whoever told you that motor does not have roller bearings doesn't know what he is talking about. Judge his credibility accordingly.

 

[JB]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

OMC said (in 1964) to run it with 24:1. It is fully "frictionless" bearings so many guys safely run 50:1.

Were it mine I would use Walmart SuperTech outboard oil or another TC-W3 rated oil, at 24:1.

High Trim and F_R are first rate experts on RDs and any other OMC product. I absolutely trust their judgement.

 

[1946Zephyr]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

what about me?

 

[F_R]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

Well you aren't too shabby either.

 

[1946Zephyr]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

Thanks Frank. I happen to be a proud owner of a couple old RD's and Larks myself and tinkered with bunches of them.

I gained a couple and sold one this last weekend. That '57 Big Twin I got sunday is sure a beauty. It's going into my "prize posession collection"

mobydick: As far as oil goes, I like the Valvoline 2 stroke oil too. I've used Valvoline, since my early days of driving and had grrrrrreat results from it. If you would like a good parts break down on your motor, then you can go here:

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/379272/37927200001.htm

It's for an RD model, but the RD is pretty close to the RDS, with the exception of the electric start and automatic/electric choke. The powerheads and all are the same though and the rest of the construction. Like JB said, these are friction free motors. All the moving parts, such as wrist pins, rods and crank are riding on needle bearings. The RD's since 1951 were set up like this, except for the wrist pins. I believe it was about 1955, when the major changes took place on the RD, all of it was needle bearing.

 

[JB]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

what about me?

I was commenting on the advice already given, Z. You hadn't posted yet. I agree that you are in that same class.

 

[mobydick]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

Thanks everyone for the quick and informative responses. It is nice to have such easy access to all of your experience and advice. I appreciate you taking the time to respond.

 

[1946Zephyr]

Re: 1963 Johnson Super Seahorse 40 HP (RDS-25D) fuel/ oil ratio

Thanks JB Yea, I haven't been here much lately. Been playin' with the new motors.

Enjoy that RD, mobydick. They're tough old motors and quite reliable. A fellow member here just acquired my 62 Lark IV and he's going to have fun with it as well.