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AZUDO
07-16-2006, 03:48 AM
Have 7530T in jetboat. I want to use 3 or 4 different curves for different tracks. Obviously I have no gears, so my question is which color wire/s to 12v to run simple retard curve?
Exactly how do I set my static timing? I want all in 40@ around 4000 with retard from there up.

I 12v the dk blue thinking that we tell the unit we are in 1st all the time.
This seemed ok except that when we put a timing light on it was idling @40 and retarding as revs came up rather than the other way round. What have I done?
Please help in words of one syllable.

SteveM
07-16-2006, 03:07 PM
Below 800 RPM use the Start Retard for your intial timing then begin your first gear curve at the same start retard valuer ramping up to your maximum timing at 4000 RPM them ramp your retard in above 4000 RPM.
For example if your maximum timing with no retards is 40 deg BTDC and you want to start at 20degBTDC at start up then allow timing to ramp from 20DEG to 40 deg at 4000. Set Start retard to 20Deg, set the first gear curve at 800 RPM to 20Deg and the next point on the curve to 40 deg at 4000 RPM, set your lowest timing at your revlimit speed or 12,500 RPM. You will need to apply +12 volts to the dark blue wire at startup and keep it connected. Check to see that the launch retard value is set to zero deg or else extra retard will result. Optionally you could generate the same timing curve for last gear as well so that at power up if the blue wire is not at +12volts the last gear retard curve is activated giving you your desired retard curve above 800 RPM.

AZUDO
07-25-2006, 06:03 AM
:confused: Hmmm. Seem to have sorted the "one curve" deal by copying curve to all gears and only connecting battery power and switched power.
Timing was erratic. As far as we can tell, we had EMI from leads to coil harness, have moved harness and seems to have fixed. Now have crackle at 6000 and plugs are reading rich. Could this be low resistance leads? Would appreciate all input. Thanks.
P.S. Posted problem a week or so ago and did not receive reply from msd tech.

msdtech4
08-04-2006, 11:47 AM
AZUDO,

Here are several items that you can check, first the only 2 wires that should be physically touching the coil, should be the orange and small black of the MSD unit. Check voltage at higher RPM's it should maintain above 10 Volts, if voltage is falling to much this can cause a miss. The wires that go from the MSD unit to the distributor, make sure these wires are not close to any other power wires, try to isolate these wires away from any other power wire or spark plug wires. If you have already tried isolating these wires, you may want to check spark plug wires for resistance, to much resistance on a wire may cause alot of RFI noise. When checking the resistance, shake them around and see if there is any resistance change or breaking up. If you have any electrical component like a electric fan or water pump try to shut these items down for testing purposes and see if it clears up. These items can cause the engine to miss at higher RPM's. Keep in mind we do also recommend using a crank trigger with the digital boxes as this is the most accurate way of triggering the ignition.


Thanks,
MSD Tech4