On my first outing of the year I noticed a miss in my 85 Evinrude 90 hp model E90TLCOS which I suspected was bad fuel left over from the season before. I drained the tank of the remaining 7-8 gal of fuel, replaced the water separator filter and pulled the spark plugs for replacing. I was disappointed to find the plug from the lower left cylinder exhibited a milky sludge (pic) and a bead of water still clung between the two contacts.
Assuming a blown head gasket I conducted a compression test to confirm my suspicion but found all cylinders relatively equal at 105, 104, 108, 106 (since I acquired the boat the readings were low but seems to run fine) The 104 reading was from the cyl. with the badly fowled plug. Ignition spark is good in all cylinders.
Since I will be needing to replace some gaskets what other issues could be the cause of water entering this one cylinder? Is it wise to replace the water passage deflectors as well? Also, the parts diagram for my model # here on Marine Engine shows a "bubble back" outer exhaust cover but mine is flat?
Assuming a blown head gasket I conducted a compression test to confirm my suspicion but found all cylinders relatively equal at 105, 104, 108, 106 (since I acquired the boat the readings were low but seems to run fine) The 104 reading was from the cyl. with the badly fowled plug. Ignition spark is good in all cylinders.
Since I will be needing to replace some gaskets what other issues could be the cause of water entering this one cylinder? Is it wise to replace the water passage deflectors as well? Also, the parts diagram for my model # here on Marine Engine shows a "bubble back" outer exhaust cover but mine is flat?
