1979 Evinrude 115 hp acts like running on 2-3 cyl.

[Sherman]

This happens only on startup. The engine starts and idles ok but runs poorly for first minute after I move the throttle to mid range. After this minute something kicks in hard and the engine runs fine the rest of the day. Although, last trip this happened once after repeted stop and starts at different fishing holes. I have rebuilt the carbs twice, replaced all the coils and everything else electrical seems to check out ok in the driveway. I have been working this problem for over two years don't know what to do next.

 

[fireman57]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

Does it only run this way on a cold start? You might have to let her warm up a few minutes. Maybe your choke is sticking on and then releasing. It also could be a coil breaking down even though you say you replaced them. check the ground wire and make sure it has a good clean connection and that it is making good contact with the plug.

 

[Sherman]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

Thanks Fireman for the reply. I will check the choke tomarrow. Ya I would say it is almost always a cold start problem. But it is a ways out of the harbor and I warm it up at the dock. Probably a total of 15 min at idle. But when I put the throttle forward this thing acts like it's running on three cylinders for about 1 min. then it takes off.

 

[Walker]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

What plugs are you using and what are they gapped at.

 

[Solittle]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

After it is good and warm and you have run it WOT for a while - - if you shut it down for a bit & restart it, will it run poorly as if it were cold?<br /><br />What you describe so far still points to some crud in the carbs.

 

[fireman57]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

The new coils that you bought, were they already assembled or did you have to put them together yourself? If you had to put the plug wires in yourself then you might not have gotten it seated well in the powerpack. Went through this with a 77 35hp and pulled my hair out for over a month.

 

[Sherman]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

Well on the spark plug issue right now I have a set of NGK BR7HS10 in although this was just another attempt as I was using the Champion number out of the factory manual. Both were had gap set a .40 per the manual. I did try .35 with no change. It does generally run great on the second and subsequent start-ups. When I installed the new coils I souldered the primary wires together after removing the rubber connector. The new coils were different with separate spark plug wires and I did find one of the plug ends with high resistance during one of my checks and thought I had found the problem but alas no. Thanks again for any help. I still have to check the choke operations. Do you think it makes a difference on the choke if I actually start the engine or not.

 

[Walker]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

I'd try Champion L77JC4 or QL77JC4 gapped at .030 and see if that helps.

 

[Sherman]

Re: 1979 Evinrude 115 hp acts like running on 2-3 cyl.

I checked the choke today and they seem to open and close fine. I will put in a set of the L77JC4 plugs before I go out the next time. Can the power pack and stator check ok but still be bad? I could look around for some used parts as I understand these parts are expensive. I also went through and cleaned all the ground connections right before my last trip. I saw a post for a junk motor like this for 150 I thought of buying something like that and just start trading parts.