|Posted on Sunday, July 03, 2005 - 06:49 pm: ||
Woodworker looking for some engine advice...
I've got a pair of P-392's in a 1953 42' Chris Craft Constellation. I have just recently purchased the boat and the lovely engines (an impressive 325.8 hours total or at least that is what the Hobbs says, maybe this was after the rebuild?).
I am not able to obtain 4000 RPM under load. The engines run, idle and start fine. I'm able to obtain 4000 RPM without the transmission engaged. However when I attempt to demand power above 3000 RPM, the engines just won't respond (max RPM is 4000 according to the plate on the cylinder cover). I've noticed the exhaust smoke tends to be black (but only when under load). I have recently replaced the carb's on both engines. I'm wondering if at some time someone put on some props that just were not built for these engines? Supposedly this boat gets up on a plane and I would like to be able to do so again. I have replaced the carbs on both engines and am contemplating if there is a fuel/air mixture problem, but that doesn't seem to be the problem while not under load.
The starboard engine is continually backing down after about 5-10 minutes of operation under a load. It tends to hold 2000 RPM well but as I advance to regain 3000 RPM the RPM drops back down as if the engine wants to quit. I'm thinking a fuel demand problem? Where should I start? The prevoius owner must have had a similar problem, the fuel filter had been replaced as well as the pump. I'm wondering if this relates to Problem #1?
I would appreciate any help, looking to try to enjoy the summer in Boston Haba!
Post Number: 8
|Posted on Thursday, July 07, 2005 - 10:25 am: ||
Try opening the main high speed needle on your carb 1 to 2 turns.
Post Number: 2
|Posted on Sunday, July 31, 2005 - 10:43 pm: ||
Have you checked the timing?