As Kevin states in not so many words... do not reply with generalities such as good spark, great compression... replies which really has no meaning. You wouldn't want us advising you to take that rubber covered doo-dad from the top area of the carburetor and move it to the other side! You'd be flying back at us with... What the hell is this guy talking about, what doo-dad to which side of what?
On a flushette, out of the water, any engine will sound pretty good... and loud, especially a looper. However, usually it really isn't and the fact that the engine will not run properly (or not at all) when in the water proves it.
Standing in back of the engine, facing the spark plugs, the cylinders are numbered as follows on that 1986 Johnson 120hp Loop Charged engine:
2.....1
4.....3
* - All spark plugs must be removed during both tests:
* - Compression - What is the actual individual psi reading of the numbered cylinders?
* - Ignition/Spark - The spark must jump a 7/16" sir gap with a strong blue lightning like flame... a real SNAP! Does it?
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You state " had carbs checked (above my pay grade)" <--- What does this mean?
At the present time, I can only assume that you mean that the mechanic simply glanced at the carburetors, smelled the stale gasoline, then gave you a outrageous cost estimate to clean them which you couldn't afford.... so the carburetors are as they were in 2013 and NOT cleaned or/and rebuilt. <-- If this is the case, I can guarantee that the carburetors are fouled, gummed, clogged simply due to sitting for six (6) years.
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Air gap spark testers can be found at any auto parts store... or build the following:
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(Spark Tester - Home Made)
(J. Reeves)
You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:
A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.
Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:
..........X1..........X2
.................X..(grd)
..........X3..........X4
This can obviously be modified to a 6 or 8 cylinder setup tester.
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Get back to us with what you find and we'll do what we can to help you.