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1958 Speed Twin.

JarheadSGT

New member
I just gained a 1958 Speed Twin 18 hp outboard. Has compression of 108 top 106 bottom, so i know it is not going to be a race engine. I need to know how to put a fuel pump on it, and how to check for spark.
I think it needs thirty to one mix, but if I recall correctly, they just used regular motor oil in the mix.

Also, do these motors have a preferred spark plug? it had autolites in it, but all my other jonnyrudes had campion plugs. Any help, or comment would be apprecieted.

When I get it running it will go on a 1952 lund 12 ft

Thank you.
 
You can install a fuel pump from a later model but this means drilling a hole in the lower side cover of the block so that there's air flow to the pump. Item 44 in the diagram here: http://www.marineengine.com/parts/j...&manufacturer=Johnson&section=Powerhead+Group
The later fuel pumps bolt to the outside of this cover. As the piston rises and falls, it pushes a puff of air out the hole against a diaphragm on the pump which in turn pumps gasoline.

Or, just find yourself a vintage pressurized type fuel tank. It's the kind with the double hose that gets compressed air from the crankcase.
Yup regular straight SAE 30. I believe the mix is one quart in a 6 gallon tank. I guess that's 24:1
Spark plug is UJ4J Champion
 
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An 18 HP would be labelled a " fastwin " I thought.------Should be easy to find a newer bypass cover ( up to 1976 models ) to fit a fuel pump.
 
Yeh they're labeled as Fastwin and Super Fastwin. I forget what makes it "super". Maybe 15hp version is plain old Fastwin and the 18 is the Super Fastwin? Who cares really.
I have one of each. The super is electric start and electric choke (which is totally whack-ass)
 
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