My 3.0 GS MNCS when set to base timing w/ shunt to 0 degrees per the manual, it starts and idles fine, but when going above 1/3 throttle it stutters and backfires. Based on what I have read it would appear to quite possibly be a lean fuel issue. However, if I advance the timing with the shunt to about 4 BTDC the backfire goes away and acceleration smooths out and the boat sounds/runs pretty well except for low WOT. If I advance the timing a few more degrees the boat sounds/runs excellent and it hits WOT without a problem.
Am I incorrect in thinking that I should focus on ignition or the timing chain with this issue? I don't want to mask an issue, but I feel like if it were a fuel issue I would not be able to clear up the backfire and lack of WOT just by advancing the timing.
Your input is much appreciated. Thanks in advance!
Am I incorrect in thinking that I should focus on ignition or the timing chain with this issue? I don't want to mask an issue, but I feel like if it were a fuel issue I would not be able to clear up the backfire and lack of WOT just by advancing the timing.
Your input is much appreciated. Thanks in advance!