70 hp Evinrude stalling

[richardbrown67@yahoo.com]

1980 Evinrude 70hp starts great, running fine in all respects, for 10 mins or so. Then it cuts to very low power, runs a while longer, and then finally stops and won't start again. Could this be a water problem? Themostat not opening, causing overheating? Pee hole discharge is strong. For a while it was killing the battery in this process, but I replaced the rectifier and now the charging system shows 13.5 volts (maybe more - I haven't been able to check it under a load.) and the last time this happened the battery stayed strong. So - any ideas? This motor is on a 32' pontoon houseboat so getting it out of the water and to a repair shop is a chore. Hasn't really had any service for years - has been dependable till just recently. Lower unit has been in the lake water for years. Recently I did retrieve the boat from the water to change the lower unit oil. So - back to the stalling problem. Runs great for 10 minutes, stalls down, quits, won't restart. Will start the next day, and the cycle repeats. Suggestions? I'm indebted to those of you who know more than I.....

Richard

 

[Sixmark]

Re: 70 hp Evinrude stalling

I would suggest testing for spark when the problem arises, it sounds as if you may have a problem with the electronics getting warm and failing, this is usually when they will fail, then once they cool off they perform normally again.

It also wouldn't be a bad idea to check compression on all 3 cylinders, be sure to ground out the plug wires to avoid burning up ignition electronics. Each cylinder probably wont be the same as the others, what you want is for all three to be relatively close to each other. Let us know what you find out and post your results so we cn help you in the right direction

 

[mrcj001]

Re: 70 hp Evinrude stalling

Like Sixmark said, check for spark when the engine acts up. In my experience with my older `76 70 HP, it still had the orginal power pack. The thing is bolted right on the cylinder head which gets very hot and cane cause a failure.

My symptoms were running just fine then it would quit, then let the engine cool, then it would run for a short time. When it wouldnt run I had no spark on any cylinder. A new power pack solved the problem.

 

[richardbrown67@yahoo.com]

Re: 70 hp Evinrude stalling

Thanks, friends.

Can you tell me the easiest way to assess whether I'm getting a spark? I have an automotive timing light. Will that do it?

(Sorry for the simple topics... - I don't hide the fact that I'm a novice at this....)

Richard

 

[Will Bark]

Re: 70 hp Evinrude stalling

An inductive timing light will work just fine. When it won't start, just try each plug wire to see if your getting spark.

 

[James R]

Re: 70 hp Evinrude stalling

At that age I would expect the original Switchbox to fail. Quite a common thing. Iboats have a decent price on a CDI replacement. I prefer CDI to all others. They give a good hot spark and seem to last. It is a simple job.

 

[richardbrown67@yahoo.com]

Re: 70 hp Evinrude stalling

Leiutenant, can you tell me more about the "Switchbox"? location, procedure to change it, etc. 1980 Evinrude 70hp 3 cyl.

 

[mrcj001]

Re: 70 hp Evinrude stalling

The power pack is located on the starboard side of the powerhead. It has a cover on it with wires going in and out.....alittle larger than a pack of smokes.........

 

[James R]

Re: 70 hp Evinrude stalling

Go to boats.net and look at the parts drawings for your year and model. This will help with all parts identification.