Hey, I'm trying to figure out why after getting a normal range on land, I can't get it on the boat. The carbs are rebuilt, the compression is good all around. I tried different props but that didn't do it. I am considering swapping lower units with my 225.. Any other suggestions?
The terminology "good all around" doesn't really tell us anything. With all s/plugs removed, what is the psi compression reading of all cylinders? With the s/plugs still removed, and a spark tester gap set at 7/16" (Gap is important), the spark should jump that gap with a strong blue lightning like flame, a real SNAP!... Does it?
S/Plugs should be Champion QL77JC4 plugs gaped at either .040 (strong spark) or .030 (long life).
If the above two areas are as they should be, either the timer base is sticking under the flywheel or you're overlooking something (high speed jets) within the carburetors.
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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
