Re: Evinrude 88 SPL
Bob..... The 1000 idle rpm on a flushette is normal if the engine is a 20" shaft. A 25" shaft on a flushette would require 1200 rpm. The idle would drop to normal when in the water due to exhaust back pressure.<br /><br />You made no reply about the spark. With the s/plugs out, is the spark jumping a 7/16" gap with a strong blue lightning like flame? A engine will run on weak ignition to a degree, but not properly.<br /><br />The compression concerns me. The way that you explain it.... you have normal and even compression of the port bank (#2 & #4) of 130 psi, but on the starboard bank (#1 & #3) there is 120 and 125 psi respectively. I realize that ten (10) psi difference doesn't sound like much, but it is a difference that shouldn't be there and could be the start of a larger problem.<br /><br />I wouldn't recommend removing the cylinder heads right now, but keep my remarks in mind. If all else fails, then remove the heads to inspect the pistons, cylinder walls, gasket sealing surfaces etc.<br /><br />The spark plugs should be Champion QL77JC4 plugs, gapped at .040 .<br /><br />Back the carb roller away from the cam. Check the linkages between the carburetor throttle butterflies. The butterflies should open and close at the same time. At dead idle, both butterflies must be absolutely closed... not one closed and one ever so slightly open.<br /><br />The throttle butterflies should just start to open when the scribe mark on the cam is dead center with the carburetor roller... not before.<br /><br />Last resort, if all of the above is as it should be (excepting the head removal)..... then yes, I would recommend removing, cleaning, and rebuilding the carburetors with complete carb kits.<br /><br />If the problem persists after that, then the cylinder head scenario falls into place.
