Warrenfromkingston
New member
Hello everyone,
Just before I packed away my 1990 36ft Tiara last fall, I was aware that the port engine took 3-4 tried before it started, and once it started, it sounded like maybe one cylinder wasn't firing properly. It was getting too cold here in Ontario to deal with it before storage.
When the boat was Spring launched last week, I observed the same starting trend....3-4 tries before it started (no surprise). BUT in addition it would misfire or stumble a bit as I maneuvered the 100ft from my launch ramp to my slip.
The first thing I thought of doing to correct the problem was to pull the plugs and check for anything odd. No other items were adjusted or altered in the carb, timing, or distributor before this happened., so I was pretty sure I would find a spark plug issue, a spark plug wire issue, or a distributor issue, so I planned to start with the plugs and work back from there.
I am not a mechanic, just a guy with average screw turning skills and a step by step mind set.
Due to work and family commitments last summer, the boat never left the dock, except for a quick trip to the pump out and back. The only other times the engines were run would have been for 5-8 minutes every 10 days or so.
When I pulled the plugs....as expected, there was a uniform modest, (but not severe) carbon build up on each of 7 plugs . The 8th plug was perfectly clean and shinny...as if I had just installed it !!!! Is this shinny plug telling me my answer ????
This was what I was hoping to find....one or more plugs that didn't match the rest.
The owners manual calls for ACMR44T plugs but the previous owner used ACMR43T.
I'm thinking the carbon build up is most likely due to the frequent engine cycling for short periods at low/idle speeds....the engine simply didn't get hot enough to burn the fuel properly. The fact that the previous owner installed "43" instead of "hotter " 44 plugs didn't help.
I plan to put the original specified "44" plugs back in....but having a heck of a time finding them at NAPA. Their books now show a #10 plug covers both 43 and 44???
The one perfectly clean spark plug raises another issue...... Why is it so clean? Did that cylinder not fire, and the fresh gas simply poured through that cylinder and acted like a bathroom shower? Should my next step be to check this cylinders plug wire.....that what I am thinking,....
Any suggestions would be much appreciated..........
Just before I packed away my 1990 36ft Tiara last fall, I was aware that the port engine took 3-4 tried before it started, and once it started, it sounded like maybe one cylinder wasn't firing properly. It was getting too cold here in Ontario to deal with it before storage.
When the boat was Spring launched last week, I observed the same starting trend....3-4 tries before it started (no surprise). BUT in addition it would misfire or stumble a bit as I maneuvered the 100ft from my launch ramp to my slip.
The first thing I thought of doing to correct the problem was to pull the plugs and check for anything odd. No other items were adjusted or altered in the carb, timing, or distributor before this happened., so I was pretty sure I would find a spark plug issue, a spark plug wire issue, or a distributor issue, so I planned to start with the plugs and work back from there.
I am not a mechanic, just a guy with average screw turning skills and a step by step mind set.
Due to work and family commitments last summer, the boat never left the dock, except for a quick trip to the pump out and back. The only other times the engines were run would have been for 5-8 minutes every 10 days or so.
When I pulled the plugs....as expected, there was a uniform modest, (but not severe) carbon build up on each of 7 plugs . The 8th plug was perfectly clean and shinny...as if I had just installed it !!!! Is this shinny plug telling me my answer ????
This was what I was hoping to find....one or more plugs that didn't match the rest.
The owners manual calls for ACMR44T plugs but the previous owner used ACMR43T.
I'm thinking the carbon build up is most likely due to the frequent engine cycling for short periods at low/idle speeds....the engine simply didn't get hot enough to burn the fuel properly. The fact that the previous owner installed "43" instead of "hotter " 44 plugs didn't help.
I plan to put the original specified "44" plugs back in....but having a heck of a time finding them at NAPA. Their books now show a #10 plug covers both 43 and 44???
The one perfectly clean spark plug raises another issue...... Why is it so clean? Did that cylinder not fire, and the fresh gas simply poured through that cylinder and acted like a bathroom shower? Should my next step be to check this cylinders plug wire.....that what I am thinking,....
Any suggestions would be much appreciated..........
