Slick harness alignment

K

Keith Diamond

Filing Flight Plan
Joined
Jan 25, 2018
Messages
25
Display Name
Display name:
Iceman
Hey all- working with my A&P to replace both harnesses on my io-540 with a slick mag right and a surefly left. The surefly was not touched- only the harness replaced. The left mag was removed and inspected.

question to the group- and I searched for a while- how do you identify the harness to magneto alignment? The harness has 1 stamped by cylinder 1 but where is cylinder one on the magnetos? We replaced the harnesses and we cannot get any fire from both.
 
If you are referring to the ignition harness cap that attaches to the magneto with three screws, I believe it can only be fitted with one orientation on the back of the magneto (the 3 fasteners only line up one way).
When I replaced the 4 ignition harnesses on the IO-540s on my Aztec I installed the caps on the magnetos and then routed the wires in sequence to the individual spark plugs.

If you aren't getting any spark there's probably something else wrong.
 
Last edited:
Keith Diamond said:
Hey all- working with my A&P to replace both harnesses on my io-540 with a slick mag right and a surefly left. The surefly was not touched- only the harness replaced. The left mag was removed and inspected.

question to the group- and I searched for a while- how do you identify the harness to magneto alignment? The harness has 1 stamped by cylinder 1 but where is cylinder one on the magnetos? We replaced the harnesses and we cannot get any fire from both.
Click to expand...
Did you snap the mag into #1 position prior to timing the mag? is the timing light showing the Mag is timed correctly?

the #1 circle on the harness shows the #1 wire the one first to the left.
 
Yes we pinned the mag to #1 before hanging it. I see the 1 one the harness/cap but there is no marker on the mag.

We both double checked all the wires are at the correct plugs.

the surefly was not touched other than the cap- but we noticed the LeD on the surefly isn’t lighting up so it looks like a series of issues possibly.
 
Keith Diamond said:
but we noticed the LeD on the surefly isn’t lighting up so it looks like a series of issues possibly.
Click to expand...
Maybe reinstall one of the old cap/harnesses and see if you regain your spark?
 
Check the power wire to the surefly..It should have an always hot 12v wire to it. Might have touched it to ground while messing with cap and blew fuse.
 
You probably just nailed it on the left side surefly.

That will leave us with the right side slick mag also not getting fire.

anyone able to snap a pic of their harness on the right mag and label where the 1 cylinder is relative to the mag? Super appreciated.
 
All set. We did pop the fuse and without the impulse coupling she wouldn’t start. Both harnesses were on correctly.

thanks all for the conversation.
 
Pretty sure a slick cap can only fit properly in one location.
 
Since installing my surefly, I have done a lot of cleaning up between the firewall and the engine. More than once surprised myself with sparks, generally a blown fuse results. The back of the surefly is in a bad place to have an unprotected always hot power lead. I ended up covering the terminal with one of those little rubber booties that you see on magneto p-leads. No issues since. In my opinion this should have been part of installation requirements of the STC
 
In the automotive world, step one of purd near any repair is to disconnect the the battery negative terminal.
 
You must log in or register to reply here.
Back
Top