1979 evinrude 70 missing at idle

[jtexas]

Give just a bit of throttle, in gear or in neutral, it smooths out just fine. Starts without problems. Don't have a tach, but a buddy clocked my boat at 44 with his GPS the other day, which I know it won't do on two cylinders.<br /><br />Pretty sure it's the bottom cylinder, which I found out by pulling the plug wires. Also when I changed the plugs the other day that one was a just a little bit darker than the other two.<br /><br />This is the first time I checked for spark, so please excuse a rookie question: When I pulled the wire, it arced around my pliers (insulated handle). Is that normal or is there any chance new spark plug wires could fix the problem? The other two arced to the engine block but not like this one.<br /><br />Would there be any point to testing the plug wires for resistance to determine if they're shot, & if so how many ohms should I get?<br /><br />Or, what would my next step be in troubleshooting?<br /><br />thanks very much,<br />john

 

[DJ]

Re: 1979 evinrude 70 missing at idle

jtexas,<br /><br />You're no rookie.<br /><br />Anyway, a $5.00 spark checkher from an auto parts store will answer your spark questions.<br /><br />The triple cyl. 70's are very particular about clean carbs. You'll be surprised at how well they'll run on two cyls. Yours may be running on two (idle circuit) and opens up for WOT..<br /><br />My bet is on a thorough carb cleaning.

 

[imstillatwork]

Re: 1979 evinrude 70 missing at idle

the 70hp triples (and other HP too probably) do indeed hide a problem very well at idle. <br />You may not even notice if you pull a plug wire at idle they still idle at proper rpm, but with a slight miss sometimes. I simple carb cleaning or carb rebuld (cheap AND easy! Yea!!) could work wonders.

 

[jtexas]

Re: 1979 evinrude 70 missing at idle

Ok you convinced me. This'll be my first (told you I was a rookie ). My seloc manual has the rebuild procedure but doesn't mention a simple carb cleaning. A short description would really be helpful.<br /><br />Is it possible, and would it make sense, to just do the one?<br /><br />thanks very much,<br />jtw

 

[imstillatwork]

Re: 1979 evinrude 70 missing at idle

as easy as it is, go ahead and do all three. check ebay for the carb kits, they are usually cheap, and oem brand if you look around.