70 hp evinrude runs perfect but shuts off randomly

I have a 1974 70 hp evinrude model #70473. It runs great.Doesn't miss, doesn't hesitate, idles good, starts easy, the hole deal. One problem though, it shuts off unpredictably. Doesn't gradually shut down. It just cuts out like I turned off the key. When it did it I put my hand directly on the head to see if it was over heating, but I can hold my hand there with out getting burned. I took apart the key switch and cleaned all the connections. Reassembled and tried again. Same thing happened. This time I disconnected the wiring harness to bypass the key and hot wired it on the starter solenoid. It ran fine like nothing happened and then shut down again. I used a kicker motor to bring me in the rest of the way. When I got home an hour later it started right up again. The first time it did it I was at full speed for about 1 minute staight. The other two times I was just moving from one spot to another at about mid throttle. I'm thinking it's problems with the sensor coils or the power pack. Can anybody help?

Re: 70 hp evinrude runs perfect but shuts off randomly

Glad to see another member on iboats sujend...welcome!<br /><br />Sounds like the problem may be heat related even though your engine is not "hotting" up. Some components like the power pack can quit working when the heat of the engine gets to them. <br /><br />Try the hair dryer test. Start the engine up on ears or in a suitable tank and just let it idle. Take a hair dryer and point it at suspected ignition components like the power pack. If the engine shuts down while pointing at a component, that would be a likely suspect to the problem. Don't forget the charge coil under the flywheel also. <br /><br />I would really suspect the power pack to be the bad boy here but guess' are hardly ever right.<br /><br />Don't hesitate to post any questions you might have.....thanks.

Re: 70 hp evinrude runs perfect but shuts off randomly

Thanks OBJ. As soon as I get a chance I'm going to try the hair dryer test and post the results.

Re: 70 hp evinrude runs perfect but shuts off randomly

Check the wires from the timer base to ign. pack, they can break from the flexing motion. Check the pack ground lead.