1977 Johnson 115 HP will not WOT

[smm96sam]

My 1977 115 Johnson runs good at low and moderate speed but will not go full open. The mechanic I bought it from told me to start it and pull one plug at a time to see if a coil is going bad. I went through the process of pulling one off and restarting it when it died for each plug and two made the engine stall but two did not. My problem is (please don't laugh) I don't know which ones to tell him are bad. If I'm at the back of the motor looking at it, which two are on the right side? 1 and 2, or 3 and 4?

 

[iwombat]

Re: 1977 Johnson 115 HP will not WOT

looking from the back


2 1

4 3

 

[tashasdaddy]

Re: 1977 Johnson 115 HP will not WOT

look at the spark plugs,, they are not directly across from each other one is higher than the other. #1 is the highest, #4 is the lowest this is the easiest way to tell.

also read about ethanol and older motors . http://forums.iboats.com/showthread.php?t=299680

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Thanks for the quick response guys. I guess my next step is to find my test light and check for bad wires before I jump to conclusions and spend money on new coils. I'm just hoping it is a bad wire or coil and not the power pack. I just had the carbs and fuel pump rebuilt, and replaced the fuel lines so i know it isn't ethanol build up.

Okay, I have a new question. I was checking the wires and discovered the the plug wires for 1 and 3 were switched. By putting them back right, should it run right now, or could it have messed up the coils? They were like that when i bought the rebuilt motor.

 

[emdsapmgr]

Re: 1977 Johnson 115 HP will not WOT

The reversed coil wires could be a problem. Usually when this happens, though-you will get significant backfiring, esp through the carbs. The switched coil wires may not be a problem if the coil leads connect properly to the power pack. You can mount them wherever you want, but they must be connected properly. You'll need to check their connections to the power pack terminals with the factory wiring diagram.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Thanks for the feedback. The wires were in the right spots on the power pack but the plug wires were on the wrong plug. When I put them on the proper plug and restarted the motor, a big puff of black smoke came out and it seemed to run okay but I still need to put it in the water and run it. Running it on a water hose doesn't show me anything. Is it possible that the coils might be okay even though they were on the wrong plugs?

 

[emdsapmgr]

Re: 1977 Johnson 115 HP will not WOT

Yes.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

I have a new question concerning my dilema. I took the boat out again today and it still will not WOT after switching the coil plugs the way they are suppose to be. Can the power pack go bad to where just two plugs won't fire? And, if that isn't possible, can two coils go bad at the same time? Numbers 2 and 4 fire but 1 and 3 don't. I'm at a loss as of what to do now. I have a new coil to put on but the boot isn't on the wire. How do i assemble it, and what are the two spring looking things for?

 

[emdsapmgr]

Re: 1977 Johnson 115 HP will not WOT

It is unlikely the coils are bad, but you can swap the coils from side to side and rewire them correctly for operation. If the problem moves with the coils, replace the bad coils. Yes it is possible to have a bad power pack. Packs tend to fail more than the rest of the ignition system. Ignition components are expensive, so proper diagnosis can save $ in the long rung. The factory service manual indicates checks for all the ignition components, power pack. stator, coils and timer base. You can get the original manual through Ken Cook Co. in Milwaukee.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Thank you for getting back to me. I switched the coils and the problem did not move with them. I put a test light on them while running and here's what I got:

#2 dim flickering #1 Bright steady
#4 Bright flickering #3 Bright steady

I am waiting for my neighbor to bring his multimeter over so we can get readings but in the meantime, does this look like a bad power pack? Shouldn't the light be the same for all four coils?

 

[ezeke]

Re: 1977 Johnson 115 HP will not WOT

A lot of the problems with the ignition on your series of V4 motors came from wiring problems, especially from poor grounds. Before you replace anything, make sure that all of the contacts are perfectly clean.

The rack that holds the ignition coils and powerpack is part of the problem, so make sure that the gounding straps connected to the cylinder heads are clean and tight as well.

If any moisture gets under the cover of your powerpack, you can have ignition problems, so you need to check it and then seal the connections.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Thank you for the quick response. I will check all of those things before replacing the pack.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

I have a new question for anyone that may know. What size socket do I need to remove the flywheel nut? I think it's 1 3/8 but not sure. I have troubleshot everything up to the flywheel to include all the ground wires and can't find the fault. The power pack and all four coils are good but the right bank (1 & 3) still has no fire. Does this sound like a problem with the points?

 

[iwombat]

Re: 1977 Johnson 115 HP will not WOT

This motor has no points. Could be a timer base issue though. How did you determine the power pack was good?

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

I put a brand new one on after swapping the coils and checking all wiring.

 

[iwombat]

Re: 1977 Johnson 115 HP will not WOT

You can change the leads from the timer-base to the power pack and retest on the spark checker. If the problem changes cylinders you can suspect the timer-base.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Those are the sensor wires (3 &4) on the power pack? I know I swapped the coil wires to test them.

 

[iwombat]

Re: 1977 Johnson 115 HP will not WOT

Yes, those are the ones. You can follow them back to the bundle that comes out from under the flywheel.

 

[smm96sam]

Re: 1977 Johnson 115 HP will not WOT

Awesome. Now, do you know what size the flywheel nut might be? I think it is 1 3/8 or 35mm but not quite sure. I don't have one big enough so i have to go buy one.

 

[ezeke]

Re: 1977 Johnson 115 HP will not WOT

1-5/16. 1-3/8 is too large.