74 omc 225 electric shift testing?

[kwk203]

My new to me 225 outdrive does not go forward. I have looked on the forums and found a little on how these drive work and some testing. I have 12 volts to both forward (green) and reverse (blue) wires when lever is shifted. When I check at the connections just before wires go into outdrive both wires have 12 volts when in forward and reverse positions. When the connections are not hooked up (just outside the outdrive) one has 12 volts and the other is dead. Shift to other position and the other wire has 12 volts and the other one is dead. Are they both supposed to be hot when in gear?

Also how do you check the ohms of the coils. I checked ohms through both wires going to out drive and got 2.8 ohms. Did I do this right? Thanks for any direction and help. I acquired the boat this way.

 

[bruceb58]

Only one is supposed to be hot at a time. To check the ohms of the coils, check one wire at a time to a ground point on the drive. Make sure the wires are not connected when you do this.

BTW, 2.8 ohms is way to low to get the value the way you measured it. It did show that the coils aren't open though which is a good thing. Each coil should be 6 ohms or so to ground.

 

[southkogs]

A couple of tests were suggested to me years ago for similar issues. You can read them in THIS topic. Roughly what Bruce is suggesting to you, with some additions.

Welcome aboard.

 

[kwk203]

Thanks guys. I did the ohm test wrong so I will do it again after work. I read the mentioned post and all my tests have checked out (except the ohm test) but when the wires are hooked up both are hot when it is in either gear. I will check for water in the lower unit and put type C oil in it. Can either water or wrong oil cause both wires to become hot when shifted into a gear?

 

[bruceb58]

If they both have voltage, you have a problem at the shifter.

 

[southkogs]

Can either water or wrong oil cause both wires to become hot when shifted into a gear?

Bruce is right ... the answer to the question here is "nope."

There's a switch in your shift remote that may be a mess. Depending on the remote you have, they can be a little difficult to fix.

 

[kwk203]

I checked the resistance in the coils, each coil has 3.0 ohms. This is with wires disconnected and each wire to a good engine ground.

I pulled the switch out and it has six wires going to it. The two in the middle are white and the grounds. Purple on the left front and rear which are power. Right are the green and blue. With all wires hooked up I shift it to either gear and the opposite is hot too. If I unplug both the green and blue wires and shift it into gear only the terminal that it is shifted to gets power.

I'm thinking the switch is ok and it is getting back feed from inside the lower unit. I may be way off.

I also went out and tried to turn the prop and in either gear the prop will not turn clockwise and will turn counter clockwise with some drag.

Thanks again for the help.

 

[southkogs]

Prop should spin freely. Something's jamming it up.

 

[VE8EV]

Disconnect the wires from the lower unit and test the ends coming from the shift switch. If the switch is ok you will get power on one wire in forward and the other wire in reverse. If you get power on both at the same time then something is messed up in your shift switch.

With the wires still disconnected, check the resistance between the two wires going to the lower unit. There should be not be any (infinite resistance).

Also, make sure your drive ground wire is good (the little wire on the outdrive between the top cover and the bolt on the pivot cap.

 

[bruceb58]

Also, make sure your drive ground wire is good (the little wire on the outdrive between the top cover and the bolt on the pivot cap.

Yes! This is very important!

 

[kwk203]

With everything hooked up except the two wires just before they go into the outdrive I get 12 volt to one wire only. I shift to other gear and get 12 volt on the other wire only. It is only when the wires are all hooked up that it shows 12 volts on both.

I will check and make sure the ground wire outside is making good contact.

The prop turns free when in neutral or the key is off. I will also check the resistance on the wires going into the outdrive again. I did this once and I got about 2 ohms resistance.

Thank you.

 

[bruceb58]

if you are getting 12V on both, I am thinking you are missing or have a poor ground.

 

[kwk203]

Ok, I cleaned the contacts of the ground wire on the outdrive. I am still getting power on the other wire when in gear. I disconnected the wires and took a jumper wire with 12 volts and as soon as I touch a wire the other one has 12 volts. switch wires and same result.

Ohm between the two wires and my meter zeros out. One wire to ground and meter zeros then climbs to 3.2 ohms. Same on other wire.

Is something in the outdrive grounding out or shorting across? Bad coil? Is it time to dig into the outdrive?

Thanks again for the advise.

 

[bruceb58]

Ohm between the two wires and my meter zeros out.

You do that test with the wires disconnected right?

 

[VE8EV]

Pull the lower off and check the shift wiring. Could be the cable is pinched or chafing somewhere. There are also splices right where the wires come out of the lower gearcase. If you don't see anything obvious then unhook the wires there and do the same tests again.

New shift cables are readily available.

 

[kwk203]

Yes the wires were disconnected. I won't get to pulling it apart till first of next week. Thanks.

 

[bruceb58]

Yes the wires were disconnected. I won't get to pulling it apart till first of next week. Thanks.

Sorry, but I had to ask. There are many on here that don't know how to make basic resistance measurements and do them in circuit.

 

[tazman85305]

Just a thought, but what if the gear oil isn't the correct, non-conductive, oil? Wouldn't he get the same results?

 

[VE8EV]

I've never really been sure exactly what the magic potion in Type C oil is but not having it wouldn't do that.

 

[kwk203]

Finally had some time to dig into it. I found bare wires where they go through a hole in the housing after they come out of the lower unit. I had to cut the wires to get the housing piece out of the way. pulled the cap thing off the lower unit and unhooked the wires.

I got 5.4 ohms on each wire to ground and 11.2 between the two. Does this sound good?

If so I can replace the wire and should be in business. Thanks a lot for the help.