I've got a 79 165 inline 6 cylinder that has developed a popping sound at throttle. Sounds like it is backfiring thru the carb... A bit of history:
I bought the motor and out drive in a 79 Marquis with bad transom as a donor for my 69 Sea Ray 185. Motor and out drive both ran great in the Marquis on test runs. Small issue with transition from idle to throttle but nothing major.
Moved motor over to new boat, new lower shift cable while it was apart. First test run showed the transition issue to be a bit more pronounced but again, no real issue if you worked the throttle a bit. After around 30 min. of moderate to fast (tops out at 34 MPH, I was hoping for a bit more) cruising motor developed this noise described at full throttle only, cruise at 1/2 throttle or so was good back to the dock (5 min. or so).
Asked about a bit and came up with the possibility of leak in intake causing lean (explained the transition issue as well). New intake gasket, checked point gap, dwell, new plug wires and it seemed to be running much better on muffs. On the lake this weekend and the popping seems worse, starting about 1/4 throttle. transition to throttle seemed a bit better at first but deteriorated as I tried retarding timing a bit to see if that helped (no luck, stayed the same no matter the timing).
Back at home and installed new points, condenser, distributor, rotor button, and coil. Still has issue... If throttle is advanced quickly at the carb motor will make popping thru carb sound, same as on the lake.
Thoughts or suggestions?
Thanks,
I bought the motor and out drive in a 79 Marquis with bad transom as a donor for my 69 Sea Ray 185. Motor and out drive both ran great in the Marquis on test runs. Small issue with transition from idle to throttle but nothing major.
Moved motor over to new boat, new lower shift cable while it was apart. First test run showed the transition issue to be a bit more pronounced but again, no real issue if you worked the throttle a bit. After around 30 min. of moderate to fast (tops out at 34 MPH, I was hoping for a bit more) cruising motor developed this noise described at full throttle only, cruise at 1/2 throttle or so was good back to the dock (5 min. or so).
Asked about a bit and came up with the possibility of leak in intake causing lean (explained the transition issue as well). New intake gasket, checked point gap, dwell, new plug wires and it seemed to be running much better on muffs. On the lake this weekend and the popping seems worse, starting about 1/4 throttle. transition to throttle seemed a bit better at first but deteriorated as I tried retarding timing a bit to see if that helped (no luck, stayed the same no matter the timing).
Back at home and installed new points, condenser, distributor, rotor button, and coil. Still has issue... If throttle is advanced quickly at the carb motor will make popping thru carb sound, same as on the lake.
Thoughts or suggestions?
Thanks,
