I have a 1996 Evinrude 115 Ocean Pro 60 degree outboard Model E115SXEDR, Ser # G04140796 that is getting a small amount of moisture into the bottom (#4) cylinder. There is no water in the fuel. I experience an occassional close hydro lock while cranking, but it doesn't stop the engine totally from cranking, but you know its close. I also get an occassional misfire at idle and off idle. Each time I go out and return, I can pull the #4 plug and it is severly rusty from the salt water intrusion. Compression is very close to same for all cylinders, although its hard to tell for sure due to bendix disengaging while cranking. This engine is the o-ring head gasket design.I have read a lot of feedback on this same problem for the same generation of outboard, but I have not seen any definitive conclusions for what the problem ever turns out to be. Can anyone share their results? Thank you.
Here is more information for anyone who can help.Compression on all cylinders except #4 is 115 psi. Number 4 cyl is 100 psi. Pulled head and found nothing wrong with O-rings nor any visual cracks in head. Cylinder walls on number 4 show residual marks from surface rust which probably accounts for lower compression. Rings are not stuck in piston as the piston can be moved around and you can see that at least the top ring is not broken. The number 4 piston has many pock marks from apparent predetination.This engine does NOT have a removable exhaust plate on the powerhead itself.Pulled the powerhead and inspected the gasket sealing surfaces between the powerhead and the mid section exhaust insert. Although it looks like any of it could have possibly seeped water into the exhaust ports, there was nothing obvious except the following.Toward the front of the engine there is a section of the flat aluminum block that serves at the ceiling to the apparent front mid section exhaust loop section. This flat part of the powerhead is near the large front motor mounts. The entire front edge of this portion of the aluminum powerhead has collapsed/cracked and has severe corrosion buildup. If not for the buildup of corrosion, it should have allowed the exhaust to have leaked from this area (assuming I properly understand that pocket to be a part of the exhaust looping), however there was no indication of any exhaust leakage through that area of gasket and metal. However, due to the amount of corrosion it is possible that there was salt water intrusion into that area and possibly that portion of the exhaust looping. I intend to fill the void area with Devcon epoxy to and replace the gasket.I also noted upon disassembly there was a small stream of light colored sludge exiting the number 4 cylinder beginning at the exhaust port of the cylinder sleeve, confirming the water/oil mix from that cylinder. However, it is concievable that the cylinder sleeve could be leaking water right at the cylinder port, and due to its proximaty it could be getting sucked into cylinder from that location. However, I wouldn't expect there to be a large spray of water from a sleeve seeping.Having said all this, I don't have a high level of confidence as to whether the powerhead base gasket is the real problem. I dont want to do the job twice. So my question is along the lines of what else should I be looking at on this design that would cause my problem?As for the crankshaft bottom seal sucking water spray into the engine, it is not likely to be the culprit in this case based on what I'm seeing.
I feel this problem may be a porous or otherwise defective casting in the powerhead block waterjacket. Has anyone been successful with lining water jacket area with epoxy. Please advise on the process and materials. Thank you.