I have a 1978 OMC Sterndrive with a chevy 305 4 barrel engine. I bought it in a negletic state, I changed the oil, and put in nice fresh fuel and had to atleast take it on the water once, to check everthing over, and well...
First Problem, I took it out on the water, and after about an hour of running ,when i was at full throttle the engine would backfire, and loose power, and sputter, I would back off the throttle to keep the thing running, then after idling for a few minutes, i could go back to full throttle and get on plane OK, for a minute or two, and same problem. I then took it home, and then changed the spark plugs, Cap, Rotor, Points, wire, coil set timing, checked dwuell, and replaced the water seperator filter.
Took the boat on the water a second time, and problem still there, but now ALWAYS at 3/4-full throttle, and a noticable POWER LOSS in all other speeds. Double checked the timing, and it was good.
Which brings me to the second problem, while limping this boat back to the trailer, I found a nice tree stump or something. Bent the brand new prop all to hell, and stripped out the drive splines on the Torq-Flo Hub. After getting the boat home, and removed the prop, I noticed that the prop shaft was "wobblie" about 1/16" of an inch. I can't find any specs in the service manual. Can i assume that the shaft should be straight with no wobbles?
And third, just before I noticed the prop shaft possibly bent, i did remove the fuel lines, checked for blockage, changed the carb. fuel filter, checked the tank vent. and only the carb filter was somewhat dirty but, not difficult to blow air throught. And then i checked the engine compression 150 in all but 2 cylinders, and 135 in the other 2 (Cyl. #1, and #8)
Which gives with the engine problem? I have a new igniton system, and the fuel system is getting there!
First Problem, I took it out on the water, and after about an hour of running ,when i was at full throttle the engine would backfire, and loose power, and sputter, I would back off the throttle to keep the thing running, then after idling for a few minutes, i could go back to full throttle and get on plane OK, for a minute or two, and same problem. I then took it home, and then changed the spark plugs, Cap, Rotor, Points, wire, coil set timing, checked dwuell, and replaced the water seperator filter.
Took the boat on the water a second time, and problem still there, but now ALWAYS at 3/4-full throttle, and a noticable POWER LOSS in all other speeds. Double checked the timing, and it was good.
Which brings me to the second problem, while limping this boat back to the trailer, I found a nice tree stump or something. Bent the brand new prop all to hell, and stripped out the drive splines on the Torq-Flo Hub. After getting the boat home, and removed the prop, I noticed that the prop shaft was "wobblie" about 1/16" of an inch. I can't find any specs in the service manual. Can i assume that the shaft should be straight with no wobbles?
And third, just before I noticed the prop shaft possibly bent, i did remove the fuel lines, checked for blockage, changed the carb. fuel filter, checked the tank vent. and only the carb filter was somewhat dirty but, not difficult to blow air throught. And then i checked the engine compression 150 in all but 2 cylinders, and 135 in the other 2 (Cyl. #1, and #8)
Which gives with the engine problem? I have a new igniton system, and the fuel system is getting there!
