1986 OMC Cobra 3.0 140 HP Starting and Tilt/Trim problem at the same time

[robertmcd88]

I recently pulled and replaced my 1986 OMC 140HP engine due to a cracked cylinder wall from a broken piston. Everything else worked fine before replacing the engine. Just in case this is easy for someone I?ll start with the problem: I have power coming from the ignition switch but no power to the starter solenoid and additionally the tilt/trim switch on the remote does not lift or lower the outdrive (it can be jumped), but somehow it (t/t switch) powers up the dash as it would if you engaged the key. I assume all three issues are related but I have no clue. Any ideas? Additional details: Not being good with electrical stuff in general I unhooked as little as possible and just laid most of the electrical stuff out like a fillet leaving just enough room to get the old engine out and new one in, so grounds, starter, blower, tilt trim plug, and thermostat wiring were all I really had to remove. As far as I can tell it is all back together the same??? If I did not cross a wire somewhere it is possible that water got into something on the engine side but not likely on the controls or dash area. It is also possible a critter may have chewed something, although I see no obvious damage I had a problem with that before on one of our cars and the boat is parked near the woods.

 

[bigdirty]

Re: 1986 OMC Cobra 3.0 140 HP Starting and Tilt/Trim problem at the same time

...........I have power coming from the ignition switch but no power to the starter solenoid and additionally the tilt/trim switch on the remote does not lift or lower the outdrive (it can be jumped), but somehow it (t/t switch) powers up the dash as it would if you engaged the key.

Sounds to me like you have a ground missing somewhere, the power from the ignition switch may be there, but its likely the dash is 'using' the trim switch to find its path to ground. (instead of the trim pump solenoid, which would then likely work) Can you 'jump' the starter and make it kick over?

...........Not being good with electrical stuff in general I unhooked as little as possible and just laid most of the electrical stuff out like a fillet leaving just enough room to get the old engine out and new one in, so grounds, starter, blower, tilt trim plug, and thermostat wiring were all I really had to remove. As far as I can tell it is all back together the same??? I......

Its not that complicated in most boats, usually, just need to have all your connections good and clean, and grounded well. Check battery connections first, and the main wiring harness at the motor (connections there can get corroded/loose) and make sure everything IS in fact hooked back up as it was before the motor pull out.

 

[robertmcd88]

Re: 1986 OMC Cobra 3.0 140 HP Starting and Tilt/Trim problem at the same time

Thank you for taking the time to read and respond to my post. I?ll clean all the grounds and wiring I can over the weekend and post my results hopefully on Monday. As far as the question goes on jumping the starter: That was my first thought and it would not work. I took the starter off and the solenoid on the starter was actually bad so I replaced it. I tested it by jumping it with my extra battery before I put it back on the boat and it worked fine, but with it all hooked up again it still won?t jump, wont click, nothing which brings up another curiosity for me. There are 4 posts on the solenoid 1. goes straight into the starter body 2. Winds its way back up to the relay/solenoid thingy 3. Winds its way back to the battery and 4. Winds its way to somewhere unknown to me and I can?t seem to find much on what that 4th terminal does. That 4th terminal has power all the time as if it were connected straight to the battery and I can?t seem to find out if that is normal.

 

[bigdirty]

Re: 1986 OMC Cobra 3.0 140 HP Starting and Tilt/Trim problem at the same time

..... 4 posts on the solenoid 1. goes straight into the starter body 2. Winds its way back up to the relay/solenoid thingy 3. Winds its way back to the battery and 4. Winds its way to somewhere unknown to me and I can?t seem to find much on what that 4th terminal does. That 4th terminal has power all the time as if it were connected straight to the battery and I can?t seem to find out if that is normal.

I'm assuming its a GM starter.. the one going into the starter body is fed power direct from the battery (the other large post that winds back to the batt.) when you turn the key. One of the smaller posts, (that wire that winds its way up to the relay/solenoid thingy) is the 12v 'kick' when you turn the key, which engages the solenoid. I believe the other one (your '4th terminal') would supply 12 volts to the ignition system while cranking the motor...