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First time poster - looking for help on diagnosing an '87 9.9 four stroke with no spark. Had the engine since new. About 15+ years ago, I found an early 90's 9.9 and swapped over the electric start and carb from that engine to replace the problematic thermal carb in the original engine and gain electric start. It ran great for years, but pulled it out of the water ~4 years ago and it sat on the trailer. Fast forward to today and trying to get it back in service but not getting any spark at either plug. I have the SELOC manual and have been going through the troubleshooting section, but need help in interpreting the results:
First, disconnected the white wire to the kill switch. No change, so I believe that rules out the kill switch.
Next, checked the Pulser coil. W/R to B yields 217.7 ohms, which is just out of the 173-211 range in the manual. I did the dynamic check by putting the DVM on AC volts across the W/R and B wires and saw 0.3VAC while cranking the starter. Spec is 4V no load, so this seems suspicious.
Next checked the Charge coil: Br to Blue yields 347 oms, which is outside of the spec for the 84-90's (569-625) but in spec for 91-95 (280-420). Dynamic test while cranking, no load yielded 83 VAC, which is also out of spec (95V no load). One question I had on the dynamic test for both coils is whether simply cranking the motor with the starter is sufficient to get the prescribed values in the table or does the engine have to be running? The reason I mention two different spec ranges is that I vaguely recall pulling the flywheel when I did the swap, and I may have swapped the coils at that time, but I just can't remember for sure. Sucks getting old
Next the ignition coil. The orange/black primary winding measured 0.4V which is out of spec (84-90 = 0.09-0.12 ohms, 91-95 = 0.08-0.11 ohms) . Measuring the secondary coil resistance across the two spark plug caps showed an OPEN. Spec is 2890-3910 ohms for 84-90 and 3485-4715 for 91-95. I assume I am measuring this correctly across the two spark plug caps, the manual was not crystal clear on this.
It seems like I have several readings that are out of spec. Making an assumption that not everything is bad, I'm wondering where to start? My first inclination is the ignition coil, since it shows an open when measured between the two spark plug caps. I realize that I could have a bad cap or bad wire, but it looks like the wires are glued into the coil and I am not sure how to remove the spark plug ends from the wire?
Looking for some suggestions/advice from the experts on next steps before I start throwing parts at it!
Thanks,
John
First, disconnected the white wire to the kill switch. No change, so I believe that rules out the kill switch.
Next, checked the Pulser coil. W/R to B yields 217.7 ohms, which is just out of the 173-211 range in the manual. I did the dynamic check by putting the DVM on AC volts across the W/R and B wires and saw 0.3VAC while cranking the starter. Spec is 4V no load, so this seems suspicious.
Next checked the Charge coil: Br to Blue yields 347 oms, which is outside of the spec for the 84-90's (569-625) but in spec for 91-95 (280-420). Dynamic test while cranking, no load yielded 83 VAC, which is also out of spec (95V no load). One question I had on the dynamic test for both coils is whether simply cranking the motor with the starter is sufficient to get the prescribed values in the table or does the engine have to be running? The reason I mention two different spec ranges is that I vaguely recall pulling the flywheel when I did the swap, and I may have swapped the coils at that time, but I just can't remember for sure. Sucks getting old
Next the ignition coil. The orange/black primary winding measured 0.4V which is out of spec (84-90 = 0.09-0.12 ohms, 91-95 = 0.08-0.11 ohms) . Measuring the secondary coil resistance across the two spark plug caps showed an OPEN. Spec is 2890-3910 ohms for 84-90 and 3485-4715 for 91-95. I assume I am measuring this correctly across the two spark plug caps, the manual was not crystal clear on this.
It seems like I have several readings that are out of spec. Making an assumption that not everything is bad, I'm wondering where to start? My first inclination is the ignition coil, since it shows an open when measured between the two spark plug caps. I realize that I could have a bad cap or bad wire, but it looks like the wires are glued into the coil and I am not sure how to remove the spark plug ends from the wire?
Looking for some suggestions/advice from the experts on next steps before I start throwing parts at it!
Thanks,
John
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