Gas tank compatability

Y

yam350yfm

Petty Officer 3rd Class
Joined
Dec 26, 2007
Messages
79
Can the gas tank from a 1957 FD 11 model 18hp fast twin Johnson be used with a 1966 Johnson 20hp engine? I know the oil mix between the motors is different, with the 1957 at 24:1 and the 1966 is 50:1 but can the same gas tank be used?
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Gas tank compatability

the original tank for the 18hp was a 2 line pressure tank, the 20 uses the single line tank with the primer bulb, and has a fuel pump. the answer is no. Unless you convert the 18 to a fuel pump. which is far more expensive than a plastic tank for the 20hp.
 
jbjennings

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: Gas tank compatability

No, but if you send me the FD-11 tank, I'll send you a brand new tank for your '66 johnson.:D
Sorry, I had to say it. THe '57 tank is pressurized by the motor and has a 2-line hose, one for fuel to the motor and the other to take air from the motor to the tank to pressurize it and force fuel to the motor. Your '66 needs a single line tank. You can get a plastic one at walmart for 20bucks. Those pressure tanks from '57 are really desirable to old OMC lovers, by the way.
JBJ
 
Y

yam350yfm

Petty Officer 3rd Class
Joined
Dec 26, 2007
Messages
79
Re: Gas tank compatability

Thanks for the information. The 57 is one that seized from sitting for a few years. After letting it soak with PB Blaster for a few months it still would not pull through. I pulled it apart and the rings were rusted, as were the crank bearings. Not sure what I want to do with that versus I can get the 66 for $400. It was on the back of a sail boat, so it has low hours, has good compression, etc. The long shaft will be okay as my transom is 17". I figure it will cost close to that to get the 57 parts, gaskets, coil, points...
 
K

K.B

Seaman
Joined
Jun 24, 2006
Messages
62
Re: Gas tank compatability

Hi Yam,

Used to have a '58 18 John and a '67 John 20 hp. Sold both a few months back, but if your lower unit is still good and you wanted to convert to short shaft at some point then you are in business, I'M PRETTY SURE! Don't quote me on that, but I did use the elec. start off of my 18 on the 20. Same stuff. Bet the bottom parts are too.

Enjoy, they are good ones!
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Gas tank compatability

i would make a jack plate before converting to short shaft, long shafts sell better these days.
 
samo_ott

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: Gas tank compatability

I think the LU's are the same also. They are both the same 22 cubic inch engine. Not much different on them. Most parts will be interchangeable.

And as 20hp on a sailboat? Wow. That'd be way over the hull speed. Most have 8's or 9.9's or inboards.
 
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