Stringer Electric Shift Question

[southkogs]

I'm dealing with a shift issue that I thought I solved last year ... doh!

I have a 165 Electric Shift OMC Stringer and when I push the throttle forward or pull in reverse there is a pretty solid "wham" in the back and the entire system shuts down. It was suggested before that my drive is trying to engage forward and reverse at the same time ... and I'm thinking that might be the case:

When I check current at the shift cables entering the intermediate housing I'm getting a reading on both wires of about 20AMPs when pushing forward OR reverse. Am I correct in understanding that only one wire should be drawing AMPs when pushing forward, and the other when pulling reverse?

Also, where is the best place to check the AMPs at the front controller?

I'm still learning the electric stuff.

Thanks in advance!

 

[proshadetree]

Re: Stringer Electric Shift Question

You should only have 12 volts on one wire at a time.

 

[Howard Sterndrive]

Re: Stringer Electric Shift Question

only 1 wire should be carrying current on it at any time, and neither in neutral

unplug the knife connectors and with engine off - just check voltage on the green wire (the one coming from the shifter) put meter between green wire & ground as someone operates the shifter, then check same for the blue wire

should get 12V on one in F, 12V on the other in R, and 0V on either in N

then you can switch over to ohms and check resistance of the drive coils - should be 4 to 8 ohms between either the green wire or blue wire (heading out through the transom) and a good ground

Do you have Type C oil in the lower unit?
also want to make sure the lower isn't full of lake water.

 

[southkogs]

Re: Stringer Electric Shift Question

Okay - I checked the voltage on the shift cables. It looks like I'm getting 12V to either depending on if I'm in FORWARD or REVERSE. I did get initial readings of 10.6V. Might have been the way I was using the meter, but just in case: would 10.6V cause the system to lock up and shut off?

Howard: I'm not following how to check ohms. I'm still learning how to use the meter, and I'm also not quite understanding what I'm measuring resistance on. Is it the wire from the coil to the knife connectors?

I purchased this boat last year (not having the first clue as to what an OMC stringer was) for $500. The boat is immaculate and the reason I got it so cheap was because it was doing this to the previous owner. I brought it home and checked several of the lines (not testing just looking for visible shorts) and taped two bare wires up. Fired up the engine and shifted - lo and behold, it worked! I ran the boat all last summer through July, August and in to September with no problems. Winterized and garage kept for the cold season, and this spring rebuilt the tilt motor, starter and replaced all the solenoids. Put it all back on, fired it up, shifted and "ka-wham" - right back to square one.

I've got a marine mechanic in the area who doesn't laugh at me when I say 1972 OMC. But if I can find the hitch here at home, I'd like to save the money.

Is there anything else obvious that I should be checking?

 

[superbenk]

Re: Stringer Electric Shift Question

Howard's questions about the oil type & if you've checked for water make sense. If you have the wrong oil & it's conducting electricity or there's water in there doing the same thing, your coils could be shorting out. You use the Ohm meter to check for continuity. There should be a certain amount of resistance through the circuit. If there is very little resistance, it means you probably have a short. If there is ONLY resistance, it means you have an open connection somewhere (ie, broken wire).

 

[southkogs]

Re: Stringer Electric Shift Question

Sorry - I didn't mean not to address that. I haven't changed the oil in the lower yet for the year (boat has been in the garage since last October), but I will do that tonight or tomorrow just to make sure. It did have Type C in it last year (and I'm assuming still does this year). I didn't see any sign that lake water was getting into it last year.

Thanks all.

 

[Howard Sterndrive]

Re: Stringer Electric Shift Question

the coils we're referring to are the electromagnet coils down in the lower unit. turn the boat battery off- or disconnect it, and disconnect the knifeblade connectors to the outdrive
Put your meter on ohms (lowest scale) and put the red lead to the terminal of the blue wire heading down into the drive (keep your fingers off the probe)
Put the black lead to a good ground (bare metal) on the engine block or intermediate housing.
Meter should read between 4 and 8 ohms.
repeat for the green wire.

 

[GMC2003]

Re: Stringer Electric Shift Question

Happened to me, but on the lake. The wires shorted out under speed. Loud clunk, then the boat would only go forwards, even in reverse, which made for a fun trip. What happened to me is the shift wires got pinched between the exhaust housing and the upper gearcase.

 

[southkogs]

Re: Stringer Electric Shift Question

Well ... I changed the gear lube (used type C for sure) and checked ohms. I'm gettin' 4 on both wires. I didn't see any metal flakes or chunks when I drained the gearcase. Left the knife wires off for a minute and revved up the I6 250 to make sure I wasn't barking up the wrong tree - and it did nicely. So, any suggestions on a next step (other than haul her to the marine mechanic - which is on my radar)?

 

[Howard Sterndrive]

Re: Stringer Electric Shift Question

only 1 wire should be carrying current on it at any time, and neither in neutral

unplug the knife connectors and with engine off - just check voltage on the green wire (the one coming from the shifter) put meter between green wire & ground as someone operates the shifter, then check same for the blue wire

should get 12V on one in F, 12V on the other in R, and 0V on either in N

do that test

 

[southkogs]

Re: Stringer Electric Shift Question

Howard: in all seriousness, thank you for your patience and expertise. I've seen a bunch of your posts on the forums and you are very generous in helping all of us.

Okay - with the knife connectors disconnected, I'm reading about 10v on either wire when in Forward or Reverse respectively. When the connectors are connected, I read that same 10v in both wires no matter what gear. Neutral is always 0.

With the knife connectors disconnected, I get 3.6Ω on either wire going to the stern drive.

I actually picked up another control box from a salvaged boat. I haven't cleaned it up yet, but I plugged it in just for kicks and got the same result in terms of charge to the wires.

I'm not sure which way to go next - pull the stern drive off and start chasing the wires that way?

 

[southkogs]

Re: Stringer Electric Shift Question

Pulled the drive off and checked the wires without getting into the gearbox. Everything looked fine - but I know that doesn't mean anything on these drives.

She's going to the shop this week. I'll let them take a crack at it.