1986 Mercruiser 170 won't start

[Nucem30]

New to boats and picked up a 86 Glastron with a 170hp Mercruiser. When I crank the engine it will start but as soon as I put the key to the "on" position the engine dies. <br /><br />With the key in the "on" position none of the gauges work. when the engine is cranking the gauges work.<br /><br />I did do a search and did not find anything like this.

 

[f_inscreenname]

Re: 1986 Mercruiser 170 won't start

Try a new key switch. If you havent changed any of the wiring? That would be my first stop.

 

[DJ]

Re: 1986 Mercruiser 170 won't start

nucem30,<br /><br />Your symptom is "typical" of a bad ballast resistor. I assume this is a point system distributor. You need to identify the wire that supplies voltage to the points. Starting voltage will be 12+. Ruuning voltage is around 9 volts.<br /><br />Your key switch has two posts: 1. start. 2. Run. Trace the run wire to the engine. Somewhere in between the key switch and the distibutor you will find a device with a resistor. That is your bad part.

 

[Nucem30]

Re: 1986 Mercruiser 170 won't start

Thanks for the info. I have tried a new ignition switch and get the same results. I am having a devil of a time tracing the ign wire back due to the number of splices into the wiring. Will continue and let you know what the fix is.

 

[DJ]

Re: 1986 Mercruiser 170 won't start

nucem30,<br /><br />You may want to run a temporary wire (run) back to the points to see if you can get it to fire. Remember though, a steady diet of 12 volts will cook the points in short order. You will need some type of resistor in your permanent repair.

 

[Nucem30]

Re: 1986 Mercruiser 170 won't start

Just wanted to update this post. I figured out the problem after looking at the wiring diagrams for 2 days. It ended up being a blade connector that was not attached to the ignition switch. Once that was attached I had power to my guages and then power to the points. Fired up and ran great. Thanks for the ideas.<br /><br />By the way the resister is a wire from the electric choke to the coil.