Hi guys !
Please excuse possible unprecise terms, since English is not my mother language.
My engine runs very roughly and has no power when put to gear. Looks like severe missfiring.
Idle timing is set (at cranking speed) to 2° ATDC and 24° BTDC for max. speed.
I get sparks on the 3 plugs, (rather white-yellowish than blue), even with spark tester set at 7/16 in.
Following electrical measurements seem to be OK (Clymer manual)
- Trigger : 1.2 Kohms on the 3 circuits
- Stator : 30 ohms (red to gnd) - 1.4 Kohms (blue to red) - Low Speed : 272 DVA - High Speed : 16 DVA
- Switch box : - stop circuit 265 DVA - Bias 4.5 VDC
- Coils : primary 0 ohm (meter sensitivity too low) / secondary : 935 ohms (all coils)
BUT, DVA values of Ignition coils primary input (green wires from switch box to gnd) are VERY wrong.
When measured at cranking speed (600 rpm) as for above other values, the meter rises slowly from 5 to 15 DVA, instead of min. 150 DVA
At higher speed (around 1500~2000 rpm), the value raises slowly to 30 DVA.
When disconnected from the coil, reading from green wires to gnd gives a 285 DVA value, but without any load, I doubt this value has any meaning.
I cannot understand how sparks can be produced with such a low voltage applied on a coil.
According to the various trouble shooting guides (Clymer, CDI) the switch box is defective, and I was ready to buy a replacement.
But according to a couple of marine repair shops I asked for the part and questionned, since the engine can start, and I get such sparks, the switch box is NOT defective.
I point out that the fuel system is OK. Pump, carburetors, synchronisation have been checked. Idle mixture screw is set to default (1-1/8) and may need to be adjusted, but I do not believe this is so important. It cannot be done anyway before the engine runs properly.
I would be very grateful if anybody could confirm / justify whether this switch box needs to be replaced or not.
Thanks a lot for your attention, and have a good day.
Please excuse possible unprecise terms, since English is not my mother language.
My engine runs very roughly and has no power when put to gear. Looks like severe missfiring.
Idle timing is set (at cranking speed) to 2° ATDC and 24° BTDC for max. speed.
I get sparks on the 3 plugs, (rather white-yellowish than blue), even with spark tester set at 7/16 in.
Following electrical measurements seem to be OK (Clymer manual)
- Trigger : 1.2 Kohms on the 3 circuits
- Stator : 30 ohms (red to gnd) - 1.4 Kohms (blue to red) - Low Speed : 272 DVA - High Speed : 16 DVA
- Switch box : - stop circuit 265 DVA - Bias 4.5 VDC
- Coils : primary 0 ohm (meter sensitivity too low) / secondary : 935 ohms (all coils)
BUT, DVA values of Ignition coils primary input (green wires from switch box to gnd) are VERY wrong.
When measured at cranking speed (600 rpm) as for above other values, the meter rises slowly from 5 to 15 DVA, instead of min. 150 DVA
At higher speed (around 1500~2000 rpm), the value raises slowly to 30 DVA.
When disconnected from the coil, reading from green wires to gnd gives a 285 DVA value, but without any load, I doubt this value has any meaning.
I cannot understand how sparks can be produced with such a low voltage applied on a coil.
According to the various trouble shooting guides (Clymer, CDI) the switch box is defective, and I was ready to buy a replacement.
But according to a couple of marine repair shops I asked for the part and questionned, since the engine can start, and I get such sparks, the switch box is NOT defective.
I point out that the fuel system is OK. Pump, carburetors, synchronisation have been checked. Idle mixture screw is set to default (1-1/8) and may need to be adjusted, but I do not believe this is so important. It cannot be done anyway before the engine runs properly.
I would be very grateful if anybody could confirm / justify whether this switch box needs to be replaced or not.
Thanks a lot for your attention, and have a good day.