1974 Johnson 50hp?

Texas Prowler

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Aug 30, 2015
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Also with my budget i don't have access to new outboards... Not tying spend thousands.
 

Texas Prowler

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I'll post pictures when i get time to crop the pics on the computer. I changed the power pack because i had an aftermarket one. I found one of the rectifier wires deteriorated like those old mercs so i changed it as well. Now i need to figure out the wiring on the control box so I can wire the new switch on the control box.
The cylinder head on this motor looks really good no water seepage or discoloration. I'm excited to test for spark again if i can figure out the wiring.
 

AlTn

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may find some help under the Top Secret Files Sticky...Wiring Diagrams
 

Texas Prowler

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Today I will replace the stator. I was incorrect with my last statement about replacing the rectifier. The part i replaced was the diode assembly. I'll stop by an auto part store and rent a puller today
 

Keyboardman

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Sep 10, 2015
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Flywheel nut is 1 5/16". My '74 50hp is a strong running engine. I'm still working on a rough idle though,,,,,,
 

Texas Prowler

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I got the flywheel off tonight. While i had it off i changed the stator and the timer base assembly. I'm feeling pretty confident. Next up carb cleaning, water impeller and wiring. Then fire up...any suggestions for a motor that hasn't been started in a while? That's how I'd like to treat this one. Should I pour some oil in the intake while i have the carbs off? Idk...
 
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Texas Prowler

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Ok so today I got the carbs off send cleaned the outsides. Then i opened them up and looked inside... Clean as a whistle. You could eat off the bowl clean.. New gaskets and all. All the passages are spot free. I checked for spark and got a fat blue spark glowing bright.
I pumped some gas in and the fuel pump stated leaking a tiny bit, but that's no problem. I fogged the engine with staybil fogging oil while turning it over with the starter. Then I closed the choke and jumped the solenoid and it turned over and popped a couple times. Now if i could just figure out the wiring to fire it up via key switch for a few seconds. I will order an impeller asap. So stoked!
 
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Texas Prowler

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It runs! Beautifully! Smoothly and quiet more so them my 4hp merc 2 stroke. Very nice motor. Im tuning it in a tub since I'm not a fan of the muffs. I'm going to order a impeller kit today and hope to get it on the water next week after registration and title is in my name
 

Texas Prowler

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The compression results after running today are 140psi top and 135psi bottom. The engine runs great! I've ordered the impeller kit next I replace the transom wood. Any transom wood suggestions that a local home supply store will carry? Also what's the correct spark plug and gap for these motors? The battery it's staying charged with no problem.
Thanks!
 
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Chrisravosa36

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Aug 16, 2015
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622
The lowerunit in this motor is worth the most, alot of the parts are NLA. Have you checked it out? Is it sealed properly? I would suggest pouring oil in the carbs, its just not something I would do. I would mix some 24:1 gas, a good tcw-3 Premium oil. Clean up the spark plugs, check the impeller and tube, also I would make sure all the battery leads are tight and not touching. Also if your feeling it add a little seafoam in the air intake (1 spray every 15 seconds for about 3 - 5 minutes then spray about 10 times in about 20 seconds and kill the motor, let the seafoam sit for 5 - 10 minutes and start it and run the seafoam out. Don't be afraid, its make of a petroleum based, so it combusts.

Im working on a 1974 johnson 50hp right now, got a head gasket set and rings, going to get her to run great again. This is what I would do when first starting it.
 

Texas Prowler

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The lower unit shifts freely and sounds good.I'll check the oil condition tomorrow after i drain the tub. I plan to take the lower unit off to replace the impeller kit next week. Can someone tell mewhat seals to buy for the lower unit that should be replaced to keep the unit sealed? I've seen diagrams but I'm not sure if which ones to purchase.
 

Chrisravosa36

Chief Petty Officer
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Aug 16, 2015
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Look this up on ebay, its the whole kit, It replace everything, because if water gets in these lowerunits its not the best thing...

SEAL KITS FOR Johnson / Evinrude LOWER UNIT ELECTRIC SHIFT 50hp 1971-1974
 
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