I've used this forum to solve problems before but this is the first time I've joined/posted. I have a 1979 Cobalt with the 260 hp engine I think that is the 5.7. (350 chevy engine). I have done the following... checked compression (all around 115-120), new starter, new alternator, and new carb.
Boat cranks right up and will run all day smoothly in the parking lot. Put it in the water and it bogs down. I'd say around 2000-3000 rpms. Starts popping and I've seen a little too closely down the carb when it does because there is a small explosion in there. If I lay the throttle all the way down, it will maintain that 3000-3500 rpm without the popping but still no more power than that.
Tach, speedo, and oil pressure gauge do not work. I replaced temp gauge and it works shows boat at a constant 140. All gauges needles jump to one side and then the other when I turn on the key, but the temp, gas gauge and trim are the only ones working after the boat is running. The tach needle stays maxed out and the speedo goes back to zero. Oil pressure switch goes back to zero as well. I only bring this up for insight, dont care if they work unless that could be a reason electronically the engine won't push harder.
I've read most likely culprit is timing but then I also read something about grounding tach wire when checking compression and I didn't do that. What would that have damaged by not doing? My next move is distributor cap, wires, plugs and coil. I'd think if it's a timing issue it wouldn't even run right on the hose ???? Bad coil be the reason my tach doesnt work and loss of power after 3k rpms?
Boat cranks right up and will run all day smoothly in the parking lot. Put it in the water and it bogs down. I'd say around 2000-3000 rpms. Starts popping and I've seen a little too closely down the carb when it does because there is a small explosion in there. If I lay the throttle all the way down, it will maintain that 3000-3500 rpm without the popping but still no more power than that.
Tach, speedo, and oil pressure gauge do not work. I replaced temp gauge and it works shows boat at a constant 140. All gauges needles jump to one side and then the other when I turn on the key, but the temp, gas gauge and trim are the only ones working after the boat is running. The tach needle stays maxed out and the speedo goes back to zero. Oil pressure switch goes back to zero as well. I only bring this up for insight, dont care if they work unless that could be a reason electronically the engine won't push harder.
I've read most likely culprit is timing but then I also read something about grounding tach wire when checking compression and I didn't do that. What would that have damaged by not doing? My next move is distributor cap, wires, plugs and coil. I'd think if it's a timing issue it wouldn't even run right on the hose ???? Bad coil be the reason my tach doesnt work and loss of power after 3k rpms?