DartDriver
Member
Hi All,
I have an IO-360 with dual PMAGs, 500 hours. NGK plugs with 250 hours on them.
Operation has been flawless up to now (hangared almost all the time), but circumstances have caused me to position my RV-8 outdoors for the last week (with intake plugs and a canopy cover keeping the rain out pretty well). It rained everyday, and this morning a warm front brought warm humid air after a cool night. My fuel sump check showed no water in the gas (100LL). When I peeked inside the oil access cover it was clear that condensed moisture was all over the engine, EMS box, ignition wires, etc. I use dielectric grease sparingly on the ignition harness boots (spark plug side only).Temp was 70 degrees after a 50 degree night, with high relative humidity.
I was able to get a solid initial start, which petered out after a second. That's not unusual, but there was a slightly different sound when it quit. Not the normal sound when there's just not enough fuel to keep it going (I worry about flooding the engine so I prime minimally ... with the electric boost pump the FF reads 8-12 GPH then settles down to 4 GPM and I turn it off). I believe the ignition system failed.
Thankfully, I upgraded to dual EarthX batteries last year. I ran the starter for 1.5 minutes oven the next 10 minutes, trying flooding procedures, etc. A single plug would occasionally fire, but it was more like a pop. No luck starting. Walked away until the warmer temperatures (hopefully) cleared the (presumably) moisture problem.
Returned 6 hours later after the warm, dry day had a chance to do it's magic, but had a lot of trouble:
1. Took a minute or 2 of cranking to get a plug firing.
2. Took another minute of cranking to get enough plugs to fire to start it.
3. After running for 3 minutes the mag check passed, so I know all plugs are working.
4. Ran it for 15 minutes to recharge the batteries. The starting problem seems totally attributable to moisture.
I've researched online and this does not appear to be normal, so I've attempted to identify potential problems, but I don't have enough experience to identify the culprit. Ideas, anyone? Is it:
1. Condensed moisture in the PMAGs that is limiting the spark?
2. Arcing shorts in the ignition harness or spark plug boots?
3. Deteriorated NKG plugs that are degraded by the moisture in the engine?
TIA for anyone who responds!
I have an IO-360 with dual PMAGs, 500 hours. NGK plugs with 250 hours on them.
Operation has been flawless up to now (hangared almost all the time), but circumstances have caused me to position my RV-8 outdoors for the last week (with intake plugs and a canopy cover keeping the rain out pretty well). It rained everyday, and this morning a warm front brought warm humid air after a cool night. My fuel sump check showed no water in the gas (100LL). When I peeked inside the oil access cover it was clear that condensed moisture was all over the engine, EMS box, ignition wires, etc. I use dielectric grease sparingly on the ignition harness boots (spark plug side only).Temp was 70 degrees after a 50 degree night, with high relative humidity.
I was able to get a solid initial start, which petered out after a second. That's not unusual, but there was a slightly different sound when it quit. Not the normal sound when there's just not enough fuel to keep it going (I worry about flooding the engine so I prime minimally ... with the electric boost pump the FF reads 8-12 GPH then settles down to 4 GPM and I turn it off). I believe the ignition system failed.
Thankfully, I upgraded to dual EarthX batteries last year. I ran the starter for 1.5 minutes oven the next 10 minutes, trying flooding procedures, etc. A single plug would occasionally fire, but it was more like a pop. No luck starting. Walked away until the warmer temperatures (hopefully) cleared the (presumably) moisture problem.
Returned 6 hours later after the warm, dry day had a chance to do it's magic, but had a lot of trouble:
1. Took a minute or 2 of cranking to get a plug firing.
2. Took another minute of cranking to get enough plugs to fire to start it.
3. After running for 3 minutes the mag check passed, so I know all plugs are working.
4. Ran it for 15 minutes to recharge the batteries. The starting problem seems totally attributable to moisture.
I've researched online and this does not appear to be normal, so I've attempted to identify potential problems, but I don't have enough experience to identify the culprit. Ideas, anyone? Is it:
1. Condensed moisture in the PMAGs that is limiting the spark?
2. Arcing shorts in the ignition harness or spark plug boots?
3. Deteriorated NKG plugs that are degraded by the moisture in the engine?
TIA for anyone who responds!
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