Merc25strokin
Recruit
- Joined
- May 29, 2012
- Messages
- 1
Hey guys this my first post and unfortunately its about my engine troubles.
Its a 92 mercury 25hp 2 stroke od155757. Was running fine but occasionally had to pull it twice then take off fast or before it died. Also it developed a lean pop/ sneeze when coming to a stop after running fast and shifting from foward to neutral (sounded like a really loud ear peircing "chirp"). So I tried moving the air fuel screw in and out from two and it didn't really help so its currently set back to two. I cleaned the carb but it didn't make a difference. Now the engine only starts if you pump the primer plunger a few times then once it fires shift it to foward very quickly then throttle it to keep it running. I followed this procedure and ran it for about 10 mins in the yard and pulled the plugs to see what they had to say. Top cylinder looks ok and mostly dry, bottom cylinder was more wet with fuel and covered with a grey film that I suppose is a gas/oil/water mixture.
So now I'm thinking a water leak explains the trouble starting and idling. Can anyone confirm my suspicion that the symptoms indicate a water leak, and if so where is the most likely place to find the leak? I've had my hands on many four strokes and understand the principles of two strokes, but I've never worked on a marine engine so the take down procedure and terminalogy is new to me. I can't seem to find the correct service manual seeing how they are referenced through serial numbers. Some help with that would be much appreciated as well. Thanks in advance.
Its a 92 mercury 25hp 2 stroke od155757. Was running fine but occasionally had to pull it twice then take off fast or before it died. Also it developed a lean pop/ sneeze when coming to a stop after running fast and shifting from foward to neutral (sounded like a really loud ear peircing "chirp"). So I tried moving the air fuel screw in and out from two and it didn't really help so its currently set back to two. I cleaned the carb but it didn't make a difference. Now the engine only starts if you pump the primer plunger a few times then once it fires shift it to foward very quickly then throttle it to keep it running. I followed this procedure and ran it for about 10 mins in the yard and pulled the plugs to see what they had to say. Top cylinder looks ok and mostly dry, bottom cylinder was more wet with fuel and covered with a grey film that I suppose is a gas/oil/water mixture.
So now I'm thinking a water leak explains the trouble starting and idling. Can anyone confirm my suspicion that the symptoms indicate a water leak, and if so where is the most likely place to find the leak? I've had my hands on many four strokes and understand the principles of two strokes, but I've never worked on a marine engine so the take down procedure and terminalogy is new to me. I can't seem to find the correct service manual seeing how they are referenced through serial numbers. Some help with that would be much appreciated as well. Thanks in advance.