1979 Johnson 100 HP ignition question

[ceddon46]

Model J100TLR79S

Having idle issues , so am checking everything , my question is when motor is running and I take any plug wire off starboard side engine has no effect at all take any plug wire off port side engine changes , checked for spark on starboard side and have good blue spark at 7/16 , shouldnt the engine change when plug wire is removed like port side ? Help

 

[Daviet]

Re: 1979 Johnson 100 HP ignition question

You should notice a change in RPM. Have you checked the compression on the cylinders?

 

[boobie]

Re: 1979 Johnson 100 HP ignition question

Agree. Do a compression check on it.

 

[ceddon46]

Re: 1979 Johnson 100 HP ignition question

Yes I did had 120 on all cylinders last night gauge is old going to get a new one and try it , if compression is good what to check next ? I feel like this is my idling issue cause at higher rpm it can run ok on 2 cylinders but bogs down on low rpm,also I just noticed after engine is warm water only comes out of the hole under power head on port side and that is the side that it is running on no water out of starboard side after warm up and that side is not running cause remove plug wire has no effect on engine what so ever

 

[ceddon46]

Re: 1979 Johnson 100 HP ignition question

Should I remove all plugs and ground them to do the compression check ? way I did it yesterday was each cylinder by itself with other plugs and wires installed

 

[Daviet]

Re: 1979 Johnson 100 HP ignition question

Remove all the plugs, ground the plug wires or jump the solenoid, that way the ignition system is dead.

 

[ceddon46]

Re: 1979 Johnson 100 HP ignition question

ok she is fixed and running like a new , here was the problem the reason it would not idle was cause it was only running on 2 cylinders which was port side believe 3 & 4 ...had spark and fuel and good compression to the 2 cylinders that would not run which was 1 & 2 after lots of trail and error this was what fixed it , just bought the boat a week ago and previous owner had replaced the coils on the cyclinders that would not run but he wired them up wrong the 2 wires that come off the coils that go in the connector to power pack was reversed so switch the plug wires and she took off like a singer sawing machine ran awesome at the lake , so with 4 new coils new plugs and carbs rebuilt she runs like a dream... Thanks all