1975 OMC 120hp stern drive prop spins when in gear

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clayton75

New member

• Jul 29, 2016

• #1

I bought a 1975 omc sterndrive and I took it to the lake and started it up but it doesn't move the boat. When I took it out of the water, I could turn the prop both directions when it was in forward and reverse. I am hoping someone can point me in the right direction to fix the problem.
Thanks

 

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Boobie

Silver Medal Contributor

• Jul 29, 2016

• #2

Did you check the prop drive pin ?? Did you have the key turned on when you checked it ??

 

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clayton75

New member

• Jul 29, 2016

• #3

Yes The prop drive pin is in and the key is on.

 

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Boobie

Silver Medal Contributor

• Jul 30, 2016

• #4

Find the green and blue wires going down to the outdrive and see if you got 12 volts on them when you are in fwd or rev .

 

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clayton75

New member

• Jul 31, 2016

• #5

Yes both blue and green wires have 12 volts when in forward and reverse. I noticed that I only have one cable coming from my throttle on my helm. Am I not suppposed to have two cables one for the throttle and one for forward and reverse? When i run my engine in forward and reverse the prop spins the same way for each gear.

 

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Boobie

Silver Medal Contributor

• Jul 31, 2016

• #6

When you put the outdrive in forward do you have 12 volts on both the blue and green wires ??

 

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kimcrwbr1

Banned

• Jul 31, 2016

• #7

With the key off does it lock in forward gear?

 

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kimcrwbr1

Banned

• Jul 31, 2016

• #8

http://www.marineengine.com/parts/o...se+Group+120,140,165,175,190,225+&+235+Hp
I was thinking it had the hydro electric shift you dont want to apply power to both green and blue at the same time when running. Green is forward and blue is reverse with that type electric shift gearbox. With the engine off and the key on listen to the gearbox as someone shifts gears it should click when in fwd or rev.

 

Last edited: Jul 31, 2016

C

clayton75

New member

• Jul 31, 2016

• #9

With the key off the prop spins both directions it doesn't change when it is on off or in forwards or reverse.

 

C

clayton75

New member

• Jul 31, 2016

• #10

I used a test light and both green and blue wires have volts going in forwards and reverse.

 

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clayton75

New member

• Aug 1, 2016

• #11

Well I figured out what was wrong. There is a switch that puts my motor in forwards and reverse but it's not marked and I had no idea that was even a thing. So thanks for the help

 

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Boobie

Silver Medal Contributor

• Aug 1, 2016

• #12

Can you post a pic of this switch ??