Started out on a trip from Nassau to Highbourne cay Exuma with my son and his family for 4 days, I had Traveled about 5 miles and realized I had forgotten something at home.
I went back which obviously involved docking and 10 minutes at low speed and idle, when I attempted to get back up on plane mu gremlin which I have not seen in several trips returned, one engine would not rev beyond 3400 rpm (again), I shunted the test wires but no fault codes were displayed, I did the clear fault reset several times and got the double beep indicating there were no faults, but the problem remained.
My mechanic kindly met me at his shop ( he does not work on saturday) , checked for overheating with a heat gun, no issues there, checked that all cylinders were firing no issues there either took him out so he could see the problem, went back to his shop and he switched out the ECM, tried it again still would not go beyond 3400 rpm, the fact that the green light went out when the issue occurs had him stumped. He said he would have to do a more extensive trouble shooting, so we decided we would leave that for another day.
Now, heres the really strange part, I had figured out that if I revved the engine quickly in neutral, she would spin up to 5500 no problem, but if I tried it slowly she would quit at 3400.
So I trimmed that engine way out so she would have a lot of prop slip and reved to 5000 , gunned the other two and gradually trimmed the problem engine down, low and behold she ran fine, I spent 4 days in exuma covered 250 miles and never once had the issue again.
I do thing it may be related to the HO2 sensor, as I am getting a lot of soot out of the exhaust ports after each 2 hours or so running, on all three engines, they have always had a little since day one, but this is much worse than normal, there is no smoke of any kind while running at any rpm so I am also wondering if I might have leaking exhausts, anyone got any thoughts?
I went back which obviously involved docking and 10 minutes at low speed and idle, when I attempted to get back up on plane mu gremlin which I have not seen in several trips returned, one engine would not rev beyond 3400 rpm (again), I shunted the test wires but no fault codes were displayed, I did the clear fault reset several times and got the double beep indicating there were no faults, but the problem remained.
My mechanic kindly met me at his shop ( he does not work on saturday) , checked for overheating with a heat gun, no issues there, checked that all cylinders were firing no issues there either took him out so he could see the problem, went back to his shop and he switched out the ECM, tried it again still would not go beyond 3400 rpm, the fact that the green light went out when the issue occurs had him stumped. He said he would have to do a more extensive trouble shooting, so we decided we would leave that for another day.
Now, heres the really strange part, I had figured out that if I revved the engine quickly in neutral, she would spin up to 5500 no problem, but if I tried it slowly she would quit at 3400.
So I trimmed that engine way out so she would have a lot of prop slip and reved to 5000 , gunned the other two and gradually trimmed the problem engine down, low and behold she ran fine, I spent 4 days in exuma covered 250 miles and never once had the issue again.
I do thing it may be related to the HO2 sensor, as I am getting a lot of soot out of the exhaust ports after each 2 hours or so running, on all three engines, they have always had a little since day one, but this is much worse than normal, there is no smoke of any kind while running at any rpm so I am also wondering if I might have leaking exhausts, anyone got any thoughts?