OctoberSea
Seaman Apprentice
- Joined
- May 27, 2009
- Messages
- 30
1996 5.7l Volvo penta duoprop (SX-C1 outdrive) and 24' Reinell. Throttle-body fuel injection. The motor was fully winterized last fall with new fuel filter, fuel stabilizer added to the tank. New spark plugs this spring. Have started it a few times in the driveway, and just run it at idle to check things out. Started and idled fine. IT wintered with the tank just about 1/3 full, so after idling it for while I checked the racor - no water, but some sediment in the bottom of the bowl (which hasn't been checked since early last season). Added Gum-out to the tank before filling it up (added 3 small bottles for about 55 gallons fuel).
Just launched the boat last night - first time this season. Started fine, idled well. I let it warm up and then pushed it up on plane for a test run - nothing really remarkable, but it felt a little sluggish and a bit of a vibration in the mid-range (2000 rpms or so) right when I was getting it up on plane. Then it ran well for about 20 minutes. I gradually varied the rpms up and down, and then heard a clacking sound again in the mid-range (2000-2500 rmps). To give you an idea of what it sounded like... the first time I heard it, I stopped, took off the engine cover and started back up. I heard it again, and was sure that it was a plastic trim tab hydraulic line slapping against the plastic cover that sits over the distributor cap and backflame arrestor. I zip-tied that down, but the sound showed back up. I slowed down a bit, and the clacking quit, but I could feel the motor being sluggish again, then (with my hand off the throttle) - surging up and down a bit. Not huge surges, but enough to pick up a MPH or two on the GPS. I don't know much about this motor, but it made me guess some kind of intermittent firing, because I could feel the power up when it would 'catch' or fire, then lay back for a few seconds, then pick back up. No stalls.
Like I said, the sparkplugs are new, and I added gum out that day... Could I have dislodged some junk that's clogging the fuel injection? Should I try replacing the cables, cap, rotor? What in the world was that clacking? Thanks - I really appreciate any advice.
Just launched the boat last night - first time this season. Started fine, idled well. I let it warm up and then pushed it up on plane for a test run - nothing really remarkable, but it felt a little sluggish and a bit of a vibration in the mid-range (2000 rpms or so) right when I was getting it up on plane. Then it ran well for about 20 minutes. I gradually varied the rpms up and down, and then heard a clacking sound again in the mid-range (2000-2500 rmps). To give you an idea of what it sounded like... the first time I heard it, I stopped, took off the engine cover and started back up. I heard it again, and was sure that it was a plastic trim tab hydraulic line slapping against the plastic cover that sits over the distributor cap and backflame arrestor. I zip-tied that down, but the sound showed back up. I slowed down a bit, and the clacking quit, but I could feel the motor being sluggish again, then (with my hand off the throttle) - surging up and down a bit. Not huge surges, but enough to pick up a MPH or two on the GPS. I don't know much about this motor, but it made me guess some kind of intermittent firing, because I could feel the power up when it would 'catch' or fire, then lay back for a few seconds, then pick back up. No stalls.
Like I said, the sparkplugs are new, and I added gum out that day... Could I have dislodged some junk that's clogging the fuel injection? Should I try replacing the cables, cap, rotor? What in the world was that clacking? Thanks - I really appreciate any advice.
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