Ran the boat yesterday and the things have definitely improved. I'm idling about 625 in gear and able to dock without killing. If i'm in a long now wake zone I'll advance the throttle one detent which bumps rpm to 750-800, sometimes will leave one in neutral and one in gear. Either way seems to work fine, so I'm headed in the right direction. I only started the engines a few times over concern of the kickback issue, fortunately everything worked as it should. I plan to reduce the start retard from 10 to only a couple of degrees since that's all I'm getting anyway. The boat was essentially floating when I made the last round of carb adjustments so I don't think float level was working against me but I do need to verify float levels anyway for good measure. My plan is to put them closer to the bottom of the glass although Holley says half glass. Seems like a boat would need a little cushion. Running the boat and warming engines seemed to make very little difference in idle quality. It idled the same after about a minute as it did at full operating temp. In fact there was condensation all of the manifold and carb so I don't think the Dart single plane manifold every really warmed up. I think the fresh plugs helped although they still came out pretty dark. I did a lot of idleing and docking before putting it on the trailer. I guess I need to go run it and check the plugs and see if they clean up any.

In any case I've made improvement and can at least use the boat now while I try to dial things in. i have an innovate AFR, I need to get bungs welded in the tail pipe so it'll read properly. I tired using their tail pipe clamp but both idle and cruise AFR's were way lean, like 26 idle and 17 cruise. My plan is to mount the sensor permanently before I really do any further tuning,

Thanks to all that participated in this chat so far. The idle stabilization seems to work better with lower initial timing. I'll be interested to see how well stabiliztion works once the plugs stop coming out black. On the flip side the device providing the stabilization appears questionable when it comes to start retard. So if you can get it started without destroying a starter it should idle better, LOL!

I just stumbled across this video explaining rotor phasing.


One of the first things mentioned was starter kick back. After watching the video I can see how at some point the spark could jump from the rotor to the wrong terminal on the cap. As I understand it no special rotor concerns exist when using the Daytona Sensors with a MSD Pro Billet distributor. I would imagine that the more retard (delay) that is in play the more the phasing becomes important. I haven't fully digested all of this to come to any conclusions regarding my kick back issue. But it seems that the more retard in play the more important it is for everything else to be perfect.

If I understand things correctly 22.5* is half way between any 2 terminals on the cap, any additional delay and the spark could likely jump to the next cylinder. My trigger is at 38* but I don't think I'll ever be more than 36 when I'm finished tuning and I think my starter is more than capable of starting above 20* initial. I think I'm going to reconfigure things for 36* trigger with total timing set to 35*. I'm going to set my initial at 16* and turn of start retard. This would put my maximum amount of retard at 20* and leave me a little more tolerance between potential crossfire.

Good explanation and I think you`re on the right track. That may even by why Daytona doesn`t allow the timing at start to be retarded past that 13.5 per log. ??
Only one of my engines had a hickup every now and then with start retard at 10* .. I put it back to 6* , was out all day yesterday no issues... we`ll see. I may turn it off completely also.
Good find

i agree to. Rotor just too far away from cap's cyl terminal and misfires/arch's to another., Good thinkin stinkin.

Be cool if we could run a much larger diam cap. And then could use a rotor like you find in some 4cyl Toyota's and such. Very wide tip rotor. Oh well.

Glad its running better. Id try to keep the floats up a bit. Too low, and you can get alot of fuel aeration into the jets. The bowls can get pretty foamy in there at wot

are you still getting that timing spike on the datalog? If it was a crossfire issue, i dont think the datalog would show the spike on it.

What kind of condition is the cap in? Is it possible you are getting tracking from the terminals?