77 Johnson 115 no spark port side cyl

[whitejamie99]

I have no spark on cyls 2 & 4. Spark is fine on cyls 1 & 3. Motor will start on muffs and sounds like its running OK. In the water it has no power and will only go very slowly. When I change the sensors, the spark moves to cyls 2 & 4 and none on 1 & 3. After doing a search on the forums, i believe this to be either a timing base problem or a power pack problem. The manual says to test with a neon test light - cant find one. How can I tell which part to replace - the timing base or the power pack. These are both relatively expensive and I would like to not guess wrong for $200 +/1 bucks.

Any suggestions?

 

[dooma_Flatchy]

Re: 77 Johnson 115 no spark port side cyl

Mine was doing the same thing as yours and I replaced the power pack and that fixed my problem. Did you change the wires from the coils at your power pack to make sure?
Yours may be a different problem though. I had the same problem as you did trying to find a neon test light. The thing about your power pack is, If your stator is bad it will ruing a new power pack, I got lucky that it was just my pack, I also found a used power pack for $40 at a well known boat mechanic in my area that has boats and motors stacked like cord wood. I would check around if you have places like that in your area.

 

[whitejamie99]

Re: 77 Johnson 115 no spark port side cyl

Mine was doing the same thing as yours and I replaced the power pack and that fixed my problem. Did you change the wires from the coils at your power pack to make sure?
Yours may be a different problem though. I had the same problem as you did trying to find a neon test light. The thing about your power pack is, If your stator is bad it will ruing a new power pack, I got lucky that it was just my pack, I also found a used power pack for $40 at a well known boat mechanic in my area that has boats and motors stacked like cord wood. I would check around if you have places like that in your area.

Thanks for the info. I only swapped out the sensor wires. Didnt swap the coils. I will try that tomorrow. Should I swap the sensor wires and the coil wires at the same time? How do I test the stator? So many questions, so little time. LOL

 

[iwombat]

Re: 77 Johnson 115 no spark port side cyl

If you swapped the sensor wires and the problem moved then you've got a problem in your timer base. With a bad power pack the problem wouldn't move.

 

[dooma_Flatchy]

Re: 77 Johnson 115 no spark port side cyl

If you swapped the sensor wires and the problem moved then you've got a problem in your timer base. With a bad power pack the problem wouldn't move.

I thought that was correct but I wasn't sure myself. There have been lots of water under the bridge since then.

 

[whitejamie99]

Re: 77 Johnson 115 no spark port side cyl

Why is it the timer base? The timer base appears to be in good shape.. no oozing sticky substances and the base moves smoothly through the throttle range and all the way to the stop. I performed Joe Reeves check but did not mess with the four retaining clamps that he said may be the cause of a sticking timer base. I guess I'm trying to understand the theory of how a faulty timer base keeps one bank of plugs from firing. It looks like it is one of the most expensive parts on the motor and I would hate to change it for nothing. The power pack looks like it has been replaced by a previous owner as it has a Sierra part # on it. It may be the original timer base and has only lasted 32 years. LOL

 

[whitejamie99]

Re: 77 Johnson 115 no spark port side cyl

New info:

I ran the checks Joe Reeves says to check the power pack. I do have some small voltage on the black/yellow wire. With the key off I have no voltage. With the key on I get a reading o 0.7 with the voltmeter set to 2 volts. When I disconnect the black/yellow wire at the key switch I still get the same reading with the key on. When I unplug the big red plug the reading goes down 0.13.

Its obvious I'm getting some battery voltage to the black/yellow wire. Is this small amount of voltage killing my power pack? Could this be the problems of no spark on the port side? How do I troubleshoot/isolate the short?

 

[jonesg]

Re: 77 Johnson 115 no spark port side cyl

any voltage on the black/yeller wire kills the PP.

not sure how to track it down from there but I'd look at the ignition key,
if the problem persists with the red plug disconnected then its at the engine end...somewhere.

 

[whitejamie99]

Re: HELP 77 Johnson 115 no spark port side cyl

Re: HELP 77 Johnson 115 no spark port side cyl

Its very likely that I will need to replace the timing base. However with the small voltage on the black/yellow wire I'm worried about replacing the power pack and then frying the new one. Here is the readouts from my testing:

Red lead on black/yellow wire & black lead on ground key off 0.00 v
Same except key on 0.07 v
remove black/yellow wire key off 0.00 v
same except now key is on 0.07 v
disconnect big red plug 0.01v

Am i right in assuming that there are 2 possible causes here? My logic tells me that the boat side harness is putting 0.06 volts on the black/yellow wire and the engine side harness is putting 0.01 volts on the black/yellow wire. I have no clue if that is correct.

Apart from buying a timing base, power pack, boat side harness and engine side harness (at least $600) is there a way to find this short/ground/whatever?

Is that small amount of voltage enough to screw up my new power pack? Last is it possible that all of the problem is in the timing base?

 

[iwombat]

Re: 77 Johnson 115 no spark port side cyl

Your particular timer base is adjustable. That being said, you will need the proper spacing tool to make the adjustment. The tool is a collar that slides over the crankshaft and you adjust the timer base pickups until they touch the collar. I've had two go out, and one was fine after the adjustment. The other needed replacement.


Edit: Add part# and edited procedure.

CDI Gap Gauge 553-9702 is recommended for adjusting the three-cylinder and four-cylinder timer base. To regap, remove the epoxy covering on the sensor pick-up fasteners and loosen the small nuts on the center bolts going thru the heat shield. Loosen the anchor screws holding down the sensors located on the side of the sensors inside the heat-shield. Slide the sensor in toward the crankshaft until it touches the gap gauge (CDI #553-9702 available here: http://www.marineengine.com/newparts/part_details.php?pnum=CDI553-9702).

Paint the face of the sensor or the trigger magnet on the flywheel, with a contact detector, and reinstall the flywheel. Crank the engine over several times and remove the flywheel, checking to see if the trigger magnet is striking the sensor face.

 

[whitejamie99]

Re: 77 Johnson 115 no spark port side cyl

Thanks iwombat. That might actually work. I will know more once I get the flywheel off.

Does anyone have any ideas about the very low voltage going to the power pack? I may have dodged one bulled with the timer base and hoping to dodge more.

 

[McGR]

Re: 77 Johnson 115 no spark port side cyl

The timer base is simply two inductors (wire coils) that mounted on a flange/ring under the flywheel. When the magnets in the flywheel whiz by a voltage is induced in the coils that fires SCR devices in the power pack.

A good general practice is to check the coils DC resistance with an Ohmeter. When good they will generally read around 10 Ohms. Sometimes other factors regarding timer base performance will come into play such as coil/sensor alignment and magnet strength. Nonetheless, the Ohmeter gives a quick idea of the electrical condition of the sensor coil windings.

 

[whitejamie99]

Re: 77 Johnson 115 no spark port side cyl

Just to finish out this thread. Its taking me forever but I have replaced the power pack, stator and timer base along with new engine side harness as well as the remote side harness. Also have installed new shift and throttle linkage. Timing was set according to Joe Reeves method (worked great) and carbs are synced. I get a bright blue spark on all four cylinders and compression in the 120's and all within 2-3 points of each other. Will start her on the muffs this evening and then to the lake this weekend. YEEHAW SHES ALIVE.