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1987 Johnson 88SPL not combusting 2 cylinders

C

Clarkbar

New member
My 1987 Johnson 88 SPL (model J88MSLCUS) is not combusting on 2 of the 4 cylinders. The engine was first experiencing intermittent power loss, where I would give WOT and I would get 50%, then get sluggish acceleration. It continued to degrade intermittently. After it stopped combusting entirely I ran it for about an hour or so still trying to get power (as Before it was intermittent)


Through initial troubleshooting, I found the power pack for the right 2 cylinders was bad (sending wrong voltage to coil) so basically not getting spark at plug. After replacing, I can confirm strong spark on all 4 plugs.


After seeing this I went and tested under full load and am still only getting 50% power. Right 2 cylinders are not combusting. After pulling plugs again to verify spark, I noted they were dry. I opened and cleaned the carb needles and jets and found no issue (they are top/bottom - does not correlate to left/right cylinders) I confirmed it is the right 2 cylinders by taking the plugs off while running and everything stays status quo, if I do that on the left, it dies.


Open to suggestions. Not sure where I am losing draw for fuel.
 

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The trouble shooting starts with a compression test.-----These motors are " world famous " in my yard for broken piston rings.----Post your numbers.
 
racerone said:
The trouble shooting starts with a compression test.-----These motors are " world famous " in my yard for broken piston rings.----Post your numbers.
Click to expand...

Did compression test on all 4 cylinders. Non combusting cylinders - top 110psi, bottom 109 psi; combusting cylinders - top 102 psi, bottom 103 psi
 
Those compression numbers are not encouraging.----But are the orange / blue stripe wires ( powerpack to coils ) on the top cylinders on both sides of the engine ??
 
Ok so good news / bad news. I had the wrong wire from power pack to coil pack probe. After I moved orange with blue stripe to top and orange on bottom, I get the engine to turn, when it combusts, it goes for like 2/3 of a sec before cutting out (noting I am running it on 2 cylinders only, the two that weren’t firing before). If I plug in all 4 cylinders it starts right up (but I want to confirm the previously bad 2 cylinders can run the engine in low power)
 
racerone said:
The sky is blue.-----That is why the orange / blue goes to the top cylinder !!!
Click to expand...

love it! Any thoughts on the 2/3 sec combustion then die? Too much oil in housing from me running it for 1+ hour on the other 2 cylinders?

perhaps I need to run it WOT for 5-10 min to open it up
 
Clarkbar said:
love it! Any thoughts on the 2/3 sec combustion then die? Too much oil in housing from me running it for 1+ hour on the other 2 cylinders?

perhaps I need to run it WOT for 5-10 min to open it up
Click to expand...
I am having the same issue with a 1996 Johnson 88SPL both right side cylinders are not firing. You can take the plugs wires off and it does not change how the motor is running. I also only have 50% power 2500 RPM max. I had a melted voltage regulator so I replaced that and the CDI box along with two new coil packs. For each cylinder that I still had no spark to now I have great spark and it is still not running those two cylinders so I’m curious to what you found out.
 
Bmerrick said:
Compression on firing cylinders 115/ 117 compression on the two cylinders that stay cold when the motor is running and are not combusting compression 111/ 108
Click to expand...
I have also now replaced the stator, timing base, still have the same problem motor runs great on the two cylinders, but the other two nothing. has anybody ever got a bad CDI box that only ran two cylinders, but not the other two?
 
Orange / blue stripe wire to the top cylinders , yes or no?-----At 108 PSI the motor would have the cylinder head removed for inspection!
 
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