boatforever
Recruit
- Joined
- Mar 22, 2006
- Messages
- 5
I have a 1984 3.7L Merc 4 cylinder with the following verified set-up, new points with a measured dwell of 28, timing measured at 4 BTC. New plugs and wires, cap, rotor and coil. Rebuilt carb and set to factory settings. Idle screw is 1.25 turns out, also i replaced the float needle with the spring load verision which eliminates flooding during idle. Compression is 155 on all 4 cylinders.
When i hit the gas hard the engine pops, aka back fire and the idle is ruff.
Usually i will change the gap or timing when the engine backfires but the engine has great power when you ease into the throttle and will pull up any skier.
Also I am not 100% sure how the timing advance, my thought is that it mechanically increases with RPM and it does not have an assisted advance which might cause the backfiring during hard throttle.
Is this normal for the motor, the ruff idle might be normal but i dont think backfiring is ok.
When i hit the gas hard the engine pops, aka back fire and the idle is ruff.
Usually i will change the gap or timing when the engine backfires but the engine has great power when you ease into the throttle and will pull up any skier.
Also I am not 100% sure how the timing advance, my thought is that it mechanically increases with RPM and it does not have an assisted advance which might cause the backfiring during hard throttle.
Is this normal for the motor, the ruff idle might be normal but i dont think backfiring is ok.
