140hp evinrude OB rebuild help!!!

whiteboynickk

Recruit
Joined
Jan 4, 2022
Messages
3
Alright i am a young outboard technician (23years old) i recently purchased what think is a 1974 140hp Evinrude V4 . The seller was gonna scrap it so i got a deal of a lifetime. Its got good spark and compression…. Give or take a point or 2 but, 90psi in each cylinder. i may have reason to believe its a frankenmotor.
Model # : 140743s
Serial # : J0002762
Ive already dropped lower unit, replaced impeller , the housing didnt look bad and neither did the gear oil but i went ahead and replaced the oil just to be safe. My next task after re stabbing lower unit is checking the thermostats and probably just gutting them . There is quite a bit of dried salt in places around the whole motor ,not much but I broke one bolt already trying to take off lower cowling so i just left it on. Im scared im gonna break more bolts if i continue digging deeper in the motor and i dont want to invest too much into the motor if i dont have too.

The main reason im here today is im hoping someone can tell me EXACTLY where i can get a service manual for this and how i can determine if this is a 1974 140hp Evinrude V4 crossflow
Or a frankenmotor or what.
A good response asap would be much appreciated as i am driving myself nuts over this.
 

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racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,439
They did not market a 140 HP in 1974 !!-----The model # is for a 1977 model !!----And 90 PSI means you need to test with another gauge.----Or charge the battery.----Or inspect starter motor and cables.
 
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Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,930
If its a salty dog, just do a heavy decarbon on it and run it till it blows. 1977 should have the high ring pistons unless motor has been into. Too many V-4's laying around for pennies than waste coins on this dog. Also its only a 115hp at prop...
 
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