1977 Evinrude 70hp / Nomad

About inboard or outboard motors.

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NomAndy
Posts: 11
Joined: Fri Aug 03, 2018 11:26 am
Location: Milwaukee, WI

1977 Evinrude 70hp / Nomad

Postby NomAndy » Wed Aug 22, 2018 9:03 am

Hello everyone,
I hope I’m posting this in the right section. Plan on having an October start date for my Nomad. I’ve acquired a 70hp Evinrude. Model # 70773S. Right now it’s on a 73 Glastron. I’ll be transplanting this motor onto the Nomad when the time comes. Here’s the problem...

After about 10-15 minutes of run time. The motor has no go at anything other than idle. Push the throttle forward and nothing. She’ll idle along just well, and starts great. I’ve replaced the plugs, wires, coils, and power pack. If you let it sit for a while and fire it back up, she goes like a raped ape for another 10 minutes and then bogs down.

Anyone have any advice?

THANKS!

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Bill Edmundson
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Re: 1977 Evinrude 70hp / Nomad

Postby Bill Edmundson » Wed Aug 22, 2018 9:17 am

Maybe, fuel filter? Or closed tank vent?

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

NomAndy
Posts: 11
Joined: Fri Aug 03, 2018 11:26 am
Location: Milwaukee, WI

Re: 1977 Evinrude 70hp / Nomad

Postby NomAndy » Wed Aug 22, 2018 9:57 am

Bill Edmundson wrote:Maybe, fuel filter? Or closed tank vent?

Bill


Definitely not the tank vent, I ran it with the cap off because I thought that might be it as well. It’s got to be something failing after it heats up. If a fuel filter was clogged my guess would be it would be starving for fuel all the time, idle or full throttle. I replaced the fuel tank and hose, primer bulb etc...I didn’t do the water pump because it was showing signs of good circulation.

My instincts constantly bring me back to electronics heating up and failing, but I don’t know what else to change that would affect spark. Ive read that stators can heat up and fail. At $206 for a new one I want to make sure before I buy one.

Thanks Bill

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Bill Edmundson
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Location: Birmingham, AL, USA
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Re: 1977 Evinrude 70hp / Nomad

Postby Bill Edmundson » Wed Aug 22, 2018 10:12 am

Bill

I threw those out because I've done both! I had an old car that acted just like what you said. It was the fuel filter.

I was towed in in the Bartender not long ago. Then I thought try the other tank. It fired right up. I forgot I had adjustable vents. I open the vent then no problem. The guy who pulled me in is a nice guy. If you ever have your boat in Orange Beach AL. Buy your fuel at Bear Point Marina. The guy that towed me owns the place. That is all he would accept for payment. (I've towed several people. Just help me next time.) Return a favor by doing a favor. It will come home someday.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

danman
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Joined: Sun Jul 15, 2018 9:17 pm
Location: Central Ohio

Re: 1977 Evinrude 70hp / Nomad

Postby danman » Wed Aug 22, 2018 3:10 pm

That motor has a heat sensor mounted beside the thermostat so if the thermostat isn't working then it will trigger. Not sure how it actually functions but it may retard spark rather than kill the engine. Something to check....


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