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1983 Evinrude 70hp idles great, no power

capnlazy

Regular Contributor
I have a 1983 Evinrude 70hp on a pontoon. Just bought it and first time out. Motor starts and idles great. I put it in gear and no problems. I start to throttle up and it begins to accelerate but then bogs down and quits. Starts right up but I can get no power. This motor has no miss or idle problems but just won't run out. Any ideas? Carburetor? Ignition problem? Any help would be appreciated.
 
Re: 83 Evinrude 70hp idles great, no power

I'm not as familiar with 2 strokes as with other engines, but if there is one thing I've learned from being on this site, it is that carbs and fuel lines are usually the culprit if it starts and runs smoothly. Also ethanol in the fuel has recently become a huge issue with all engines.
Good luck
ps: invest in an oem service manual from this site, it's worth it!
 
Re: 83 Evinrude 70hp idles great, no power

A friend says he had the same problem with a similar motor (I think his was a Johnson) and he said the problem was a bad "Hi-Speed Coil". I can't find any reference to a hi-speed coil in my manual. Can anyone tell me what it is and if it could cause this problem?
 
Re: 83 Evinrude 70hp idles great, no power

That was my plan anyway but I was just curious if anyone has ever heard of anything referred to as a "Hi-Speed Coil". I can find no reference to it in the manual or online and was wondering what it was or if it was another name for something.
 
Re: 83 Evinrude 70hp idles great, no power

You will never guess what it was and I feel pretty dumb. It turned out to be the prop. The motor came off of a bass boat and had a 14x17 prop on it. After talking to the guys at Anchor Marine in Speedwell, TN they suggested a 14x11. Boy what a difference. I still have a slight problem with stalling but will work that out. Other than that, it runs great. I knew prop size had a lot to do with performance but I still thought it would run...I was wrong.
 
Re: 83 Evinrude 70hp idles great, no power

Did u ever find out what a high speed coil is. Im having similar problems. Motor idles good revs in reverse with full power but forward has no power? my motor is a 1989 50 hp johnson any luck for u and help for me please ?
 
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Re: 83 Evinrude 70hp idles great, no power

Hi folks very new to the forum, I have a 78 Johnson 70 hp doing the same stuff, it runs great always starts but under the back pressure she won't come to full speed, I can't even manually hold the butterflies open and get her to come open, you can hear it trying at times but its really frustrating, any suggestions would be wonderful
 
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