1990 OMC Cobra Asst. Solenoid Circuit

[andrewgroup]

could someone confirm my understanding of the assist solenoid? The way I read this diagram is the Assist Solenoid gets 12 volts via a 50 amp fuse. this same 12 volt connection then makes its way the to ignition switch including a 20 amp fuse, then it goes to the shift control, assuming some sort of switch detects if the control is in the up and center position, then makes its way back to the assist solenoid to the control terminal. So when the shift control is in up/center and the ignition switch is ingaged the assist solenoid engages and send +12v to the engage terminal on the starter solenoid....<br /><br />Cars don't have asst solenoids, why did boat makers do it this way. Seems direct drive to the Starter engage terminal would eliminate the asst solenoid.

 

[pecothern]

Re: 1990 OMC Cobra Asst. Solenoid Circuit

I think with the distance from the battery through the ignition switch and the "neutral safety switch" there is a lot of voltage drop by the time it gets back to the starter.and when the solenoid on the starter is hot it requires more voltage to get it to pull in. The assist solenoid essentially gives the solenoid on the starter a direct dose of voltage straight from the battery eliminating any voltage drop to assure you can start the thing esp when the engine is hot. I had a 95 VW cabriolet that would not start after driving for a while. The problem was the starter solenoid was close to the exhaust manifold and when it got hot it needed a lot of energy to pull it in. The factory fix was geuss what. The addition of a assist solenoid. The key pulled in the assist solenoid which the gave juice straight form the battery to the solenoid mounted on the starter. Voila' problem solved. Are you having problems with it Or are them the curious type?

 

[Pete30]

Re: 1990 OMC Cobra Asst. Solenoid Circuit

I think you are right on, with 10-12 feet from the battery to the ignigtion switch and then another 10-12 feet back to the starter solenoid, there is a large amount of voltage drop. The assist solenoid fixes this.

 

[dslagle]

Re: 1990 OMC Cobra Asst. Solenoid Circuit

Sounds all good to me. But that' crazy cuz I think i'm having a problem in this same area. I have a OMC 85 V6 4.3 and it sounds like you have all the same wiring that I do. My problem is that I'm not getting any spark to the Coil. I have checked all my fuses and found that somebody previous to me, being the owner, was using one of the 50 AMP fuses wrapped on tin foil. That was not my problem. I'm not getting any juice to the Coil. I know this cuz I've replaced the coil and checked for voltage on the wires coming into the Coil. My 20 Amp and 50 amp fuses are all good. The engine trys to crank over and even did once yesterday then tried it again and nothing. I can't seem to isolate what is going on here. The salmon are running out her in Sacramento and I can't get to them. Do you think I might have something going on where the Safty Switch is. What is this Saftey Switch. I know it has something to do woth the throttle being in neutral. Where would I check to see if that is broken. I'm so lost.

 

[andrewgroup]

Re: 1990 OMC Cobra Asst. Solenoid Circuit

I'm not having troubles with this, but I am the curious type and what to understand how all of this comes together for that fateful day on the water when your stuck. I want to try and do everything in my power to prevent this by doing some preventative maintenance on connectors, wires, switches etc.<br /><br />My next circuit to tackle and mast will be the Shift / Overstroke switches and how that all interacts. I'll develop a plan of attack to eliminate it in the event of the dreaded day.