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Hello. I am new to this. I am renovating a 1983 Mercury 18XD 2 stroke that I purchased without any history and missing the carb and some minor odds and ends. I have now got all the parts but the motor is hard to start and runs lumpy. I have checked the (replacement) carb on another engine....its fine. I have checked the reeds. Compression 130 in both. Spark very healthy in both and tested on spark tester. Engine looks to have been lightly used. Last week after I ran it briefly with hose and bellows on the lower unit for water supply, I noticed trace amounts of water in (I think) both cylinders. There were tiny droplets and hard to see as I dont have a borescope (yet!) which is why I am not 100% certain if both cylinders are affected. As part of my testing I started it on number 1 cylinder only and then on number 2 only. It ran on either but number 2 cylinder was slightly harder to start and a bit more lumpy. I am 100% convinced the water is the source of my issues but not 100% sure on the source. The fuel is fine. I assume its either getting in through the exhaust manifold (possible failed gasket or failed baffle plate) or the lower main seal. I am pretty sure that a failed exhaust gasket or baffle plate leaks can cause these symptoms but do not know if the lower main seal could equally result in similar issues. I imagine a failed lower seal would only impact number 2 cylinder and number 1 would be fine. Also, would it start on number 2 as crnakcase vacuum would presumably be poor? Before I try and pull the exhaust manifold off (I am worried about breaking bolts and then finding I got the diagnosis wrong), is there anything else I can do to confirm (or disprove) my diagnosis? All thoughts and suggestions welcome. thanks for any help on this one.</p>
Hello. I am new to this. I am renovating a 1983 Mercury 18XD 2 stroke that I purchased without any history and missing the carb and some minor odds and ends. I have now got all the parts but the motor is hard to start and runs lumpy. I have checked the (replacement) carb on another engine....its fine. I have checked the reeds. Compression 130 in both. Spark very healthy in both and tested on spark tester. Engine looks to have been lightly used. Last week after I ran it briefly with hose and bellows on the lower unit for water supply, I noticed trace amounts of water in (I think) both cylinders. There were tiny droplets and hard to see as I dont have a borescope (yet!) which is why I am not 100% certain if both cylinders are affected. As part of my testing I started it on number 1 cylinder only and then on number 2 only. It ran on either but number 2 cylinder was slightly harder to start and a bit more lumpy. I am 100% convinced the water is the source of my issues but not 100% sure on the source. The fuel is fine. I assume its either getting in through the exhaust manifold (possible failed gasket or failed baffle plate) or the lower main seal. I am pretty sure that a failed exhaust gasket or baffle plate leaks can cause these symptoms but do not know if the lower main seal could equally result in similar issues. I imagine a failed lower seal would only impact number 2 cylinder and number 1 would be fine. Also, would it start on number 2 as crnakcase vacuum would presumably be poor? Before I try and pull the exhaust manifold off (I am worried about breaking bolts and then finding I got the diagnosis wrong), is there anything else I can do to confirm (or disprove) my diagnosis? All thoughts and suggestions welcome. thanks for any help on this one.</p>
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