Bang Bang update and soot comment

[Don Sargeant]

The bang bang just went away, but while trying to analyze it, a mechanic friend ran the engine up in reverse while attached to the mooring. The exhaust was pumping copius amounts of black water and left a trail of soot on the sea. Not a lot of smoke, but a lot of black water. The engine has been run for over a hour under load this way and the black stuff keeps on coming. Could the bang bang noise have been a result of a partially blocked exhaust? The engine won't run over 2100 RPM hooked up in reverse, but I can get more out of it going FWD or in neutral. I know I'm too conservative about running the engine -- I don't need it except that my wife insists that I see if it's working "just in case" so it never gets a proper workout and only shows 213 hours on the meter. Of course you always find what you're not looking for in these investigations -- I was running with the alternator bracket bolt sheared off and wouldn't have found it if the mechanic hadn't been trying to figure out the unrelated bang bang.

Don Sargeant
~~COQUINA~~
CD25D #189
Greenwich Cove



don@cliggott.com

[Don S.]

Well, we repaired the alternator bracket, cleaned the bottom and then carefully noted the RPM/smoke state underway. We got smoke at 2200 fwd or reverse, and black water at anything over that. With the clean bottom the boat reaches hull speed at 2000. The bang bang hasn't returned. But it seems to me that the engine used to run faster without smoking. Am I crazy? Tell me, 10/2 owners, what RPM do you run at? When do you smoke?

Thanks for your input,
Don Sargeant
~~COQUINA~~
CD25D #189
Greenwich Cove

The bang bang just went away, but while trying to analyze it, a mechanic friend ran the engine up in reverse while attached to the mooring. The exhaust was pumping copius amounts of black water and left a trail of soot on the sea. Not a lot of smoke, but a lot of black water. The engine has been run for over a hour under load this way and the black stuff keeps on coming. Could the bang bang noise have been a result of a partially blocked exhaust? The engine won't run over 2100 RPM hooked up in reverse, but I can get more out of it going FWD or in neutral. I know I'm too conservative about running the engine -- I don't need it except that my wife insists that I see if it's working "just in case" so it never gets a proper workout and only shows 213 hours on the meter. Of course you always find what you're not looking for in these investigations -- I was running with the alternator bracket bolt sheared off and wouldn't have found it if the mechanic hadn't been trying to figure out the unrelated bang bang.

Don Sargeant
~~COQUINA~~
CD25D #189
Greenwich Cove

do@cliggott.com