73 evinrude 115 v4 misfire

[TONY MONACO]

Hello. I have a 1973 evinrude115 v4. It runs great when I first take off but it picks up a terrible miss after it warms up and only at full throttle anyone have any suggestions. Thank you

 

[ezeke]

Re: 73 evinrude 115 v4 misfire

That could be from several causes including a fuel pump unable to keep up with the demand or ignition coils breaking down when heated.

If you are using fuel supply components of less than 5/16 ID, you may want to upgrade.

If the ignition coils are cracked, discolored, swollen or if the potting material is distorted, it would be a good time to replace them before they destroy your powerpack.

Check your fuel supply carefully for air leaks as well.

 

[TONY MONACO]

Re: 73 evinrude 115 v4 misfire

Thank you for the info. Let me ask ,do you think if all that checks out that one of the head gaskets could be bad, or separating when she gets hot

 

[tashasdaddy]

Re: 73 evinrude 115 v4 misfire

doubtful, also old wires arc to the block and the rear cowl locks. easiest way to check is start it in the dark, but those motors do not like muffs.

 

[Ksmith0110]

Re: 73 evinrude 115 v4 misfire

I have the same motor and ran it on muffs a couple of weeks ago and burned up the water pump. Not the muffs fault - I forgot to turn on the water So I replaced the water pump 2 days ago and got it running again, on muffs, and the overheat buzzer went off. This time no damage, but I quickly found out that the muffs don't seem to seal well enough to force the water into the water pump cavity. While I had the L/U off I hooked up the muffs and held the cups on both sides with my hands and the water was forced up into the water pump cavity. I put 'er all back together and started it and held the muffs and the water started to pump. Just below the rear of the cowling there are a couple of holes that have a little spray of water (like a mist) when it's working correctly.