502 timing after ignition tune up
 

Hello,

decided to replace ignition components on my 502 mpi. Cap, rotor, plug wires, pick up coil, module, coil and spark plugs. All the parts are from boats unlimited.

Got the boat to TDC, marked the distributor to block with a line as well as the distributor under the cap before taking it apart.
Replaced everything and lined up the marks on the block and have a hard starting rough idling (with the throttle bumped up) engine. I have the a and b pins jumped in the dlc plug. Rpms don’t hold too steady (-/+ 300 rpm) at 1,500 rpm and making it difficult to check set timing. Cleaned off the timing marks, and even painted them and still no luck.
Any advice is appreciated.

thank you

check your plug wires. firing order

I have verified they are the right spots. When I set my timing gun to 8 degrees and shoot the crank, it’s past 60°, when I twist the the distributor and start getting to 50 and 40 the rpms start climbing much higher.

if you never removed the distributor there is no need to mark things or move it to adjust the timing, why did you need to get it to TDC ?

I removed the distributor to replace the pick up coil when I was doing the ignition tune up.

So I have it running and idling good now. However my aligned marks before removal and now are probably 1/2” off clockwise or better. I set my timing light to 8° and rotated the distributor further than I thought I needed to and got the tdc line on the crank and the timing cover mark aligned. Is this normal to be that much different?

I’d post a picture but can’t until I reach 10 posts

if you had to reclock the distributor and its that far off then I think the wires were one hole off when you replaced them

Hmmm. I’m looking at my old cap with the wires still on. I removed one wire at a time, and pulled them back, ran the new wire to the plug and put it on the new cap accordingly. I also looked at the new cap for any markings to indicate cylinder 1

I’ve looked at drawing of the distributor, but does anyone have a real photo with the #1 cylinder highlighted or circled for reference?