Evinrude 70 hp

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charlesp

Recruit
Joined
Aug 26, 2007
Messages
3
I have a 70hp Evinrude. I think it is a 1977 and I need to know what spark plugs to use. I bought Champion 828M that is what the book at West Marine said to buy, but when I searched online it says to use an 821. Also, does anyone know what ratio to use for oil/fuel mixture for this model? The guy that sold me the boat told me to use 50:1, but my boat is bogging down and will only creep at times. Thanks in advance for any help.
 
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papasage

Senior Chief Petty Officer
Joined
Jan 12, 2003
Messages
785
Re: Evinrude 70 hp

i think it would be QL77JC4. and a 50:1 gapped at 30 . that is what i run in my 1979 55 hp and a 1974 75 hp
 
jtexas

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: Evinrude 70 hp

I concur with QL77JC4 at .030 and 50:1

Bogging is a classic symptom of clogged carbs. Solution is a rebuild with new carb kits. Disassemble & soak overnight. Don't try any shortcuts, you'll just end up doing it again.

Find the model # on the engine mounting braket port side, something like "70773" - from that we can look up the year.

welcome to iboats!
 
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charlesp

Recruit
Joined
Aug 26, 2007
Messages
3
Re: Evinrude 70 hp

Thank you. I will send the motor info as tomorrow. This is an awesome site.
 
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WaterWitch2

Chief Petty Officer
Joined
Jun 14, 2007
Messages
545
Re: Evinrude 70 hp

My Clymer manual says Champion plug L77J4 gapped @ .040" for a 1975-1984 70 & 75 HP, however I'm not too impressed with Clymer. I still need to get a factory Johnson manual for my 1977 70 HP.
 
jtexas

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: Evinrude 70 hp

Have heard many folks who do mostly slow speed running or trolling open up the gap to .035 or .040 to cut down on fouling......seloc '73-'91 and '79 OEM manual both say .030 - you'll enjoy the factory manual, WW.

L77J4 superceded by L77JC4, Q indicates radio interference suppression, champion recommends it for our ignitions, my last set went about 3 years - I run 'em long as the electrode looks fairly flat across the top. Check the gap every so often. 2x per month useage on average burning about 10 gal per outing. Had a set of NGK's once, electrodes wore down I mean fast.
 
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