bud37 wrote:Source of the post390Express wrote:Source of the post It’s my understanding that my distributor is the AC Delco <a href="tel:1104060">1104060</a>, and it’s the same distributor as most of the TBI/MPI distributors for Merc and Crusader, ECU controlled timing).
Plug wires are new this year, routed the same as factory. I was checking the timing in neutral, looking at the time at idle (750), off idle around 1500, then near the full advance mark of 2800. Engine was slowly brought up to RPM and monitored through acceleration to see if it was jumping around a ton. Nothing out of the ordinary, just seemed unusually high at full advance.
Just cause wires are routed factory doesn't mean all is ok,...... I still cant figure how you are getting such high timing numbers on both engines......at idle maybe around 8 btdc and maybe full in around 32, I say maybe because I dont know what the spec actually is. It is possible to get higher numbers with a knock sensor to help control things under acceleration. Something is fishy here.
Do these engines run hot ? What does your mechanic say about the timing , he must have some opinion on those numbers....
The engines don’t run hot. The initial and total advance for the Stb motor were both high by about 10 degrees (checked 18/45, supposed to be 8-34). Changed the plugs today and took 10 degrees of timing out of it. Not much change. Mechanic didn’t offer any reason why the prior initial was set so high, it was that way when I bought the boat, I never messed with it.
Just did a little test. The motor runs fine for 3-5 minutes, then you hear a slight change, and 5 seconds or so later, the check engine soon light comes on, and it runs like hell. I left the check engine soon light on, fires it up again, ran like hell again. Shut it off at the breaker, wait 5 min., start it back up, runs great for 5 min again.
Is there a way to test the knock sensor? It appears to be on the left side of the block, as you’re standing at the front of the motor, right by the fuel pump. Also, is there a way to bypass the knock sensor to test it? (Leave the circuit open, or jump it). Knock sensor appears to connect with a quick disconnect. What’s the proper way to remove it?