Setup a 2D timing offset with MAT vs MAP. Enter how much timing (-) you want to pull at certain areas of the map.
Example


I do this for all of my safeties. If I have below 0-20 PSI oil it will wait 5 seconds and then pull -4000lbs of fuel. My engine will shut down

becareful with safeties. merc guardian mode will never ever completely shut your engine down.
our holley "guardians" limit you to about 2000rpm. reason being, you never want co completely lose control of your vessel. could be in a shipping lane, dealing with a current, or trying to avoid hitting the dock.
case in point, if my engine is overheating but im about to go over niagara falls- f@ck the engine, im getting out of there.
you want to know there's an issue sure, but keep it gentle. major power drop at high rpm can be lethal in the wrong boat. back out of the throttles hard in a cat and hang on tight.
we have used input/output to trigger a mil light or an alarm as well.

Good information above.
Regardless how he sets them up, he needs to setup some safeties. If not, might as well put a blow through carb on and start reading plugs.

Johnny, Rookie,

Tuner built in some safety triggers. OP, FP, CT, I think. All set to limit RPM. After reading the plugs, on Smitty’s advice (he doesn’t tune hardly any boat engines), he also dropped AFR at a handful of key spots about 0.2pts and smoothed the table. I’m going to Cumberland this weekend, and I’m going to have a laptop with me with the Holley software and TeamViewer installed. If anything is amiss, he can capture my laptop and make any adjustments from home. We’re not anticipating any complications, though.

Thanks. Brad.

Does the Holly system have a the ability to log data?

Wildman,

I believe so, but I have no idea how to do so. As of right now, it's in open loop and the WBO2 is out. I asked the tuner about it a couple days ago, and he said it's just about as easy to just read the plugs from this point. They tell the real story, anyhow.

Thanks. Brad.

Why doesnt the 02 sensor read? To read plugs you have to start with a fresh set, go wot shut off , "read" plugs (I couldn`t ever tell anything ) then what about midrange how you read plugs there?
When there is a o2 available why not tune off that? It`s by far the most accurate annd super easy way.
Running open loop doesnt have the system account for weather, temps, etc it`s basically a carburetor at that point. The whole point of Holley(for me anyways) is to have it compensate from 1500rpm onward.

Holley data logs , very easy to bring all that data up:
I would pull data after every weekend.

Dan,

Did you run yours closed loop? Ever have any issues losing WBO2s? I've always been told that one doesn't run closed loop in a boat because water will eventually kill the WBO2, and then you're dead in the water. Once the decision to switch to the Holley was made, the intent was to tune it and run it in open loop. Pretty much every Merc engine out there runs open loop. Would it be better to run closed loop, maximizing efficiency and output full time? Absolutely. But the juice isn't worth the squeeze in my opinion, nor that of the tuner. We've got it tuned safe; in the "rich" half of the "OK" range all around. We are going to run it this weekend and see how it does, then I'll touch base with the tuner and discuss.

The WBO2 reads just fine. We used it to tune the ECM with the tuner manually modifying the table as he watched the ECM correct from the base tune, holding his target AFR. It was really cool to watch him do this. He used the mouse pad with his index finger while he tapped on the number pad with his pinky and ring finger, manually inputting numbers on the grid where he saw need, based on the corrections he saw the ECM making to hold target AFR. The boat just kept running better and better. After a short convo between him and Smitty, he made an adjustment to the target AFR and we went through the process all over again. He was even making small adjustments to timing as he went. By the time he was done (about an hour total time), he was seeing nothing but 0% corrections from base tune, no matter what I did to the throttle. He accounted for weather, given the weather we typically see vs what we had that day. It was very obvious he'd done this many, many times.

The ONE thing I'm even remotely concerned with is that it died twice, shifting into gear, after dropping him off to pick up the trailer. It also shifted into gear several times without incident, but it did sag a bit each time. I now understand why Merc went with the Ford PWM IAC: It reacts much quicker to the sudden change in load when shifting into gear. After telling him about this, he made a quick change to something (he told me, but I don't remember) that he said SHOULD solve that problem. But we haven't run it since. We'll find out.

Thanks. Brad.

The whole point to me for Holley is closed loop compensation.
There was never a time where compensation was 0 in my case.
Water temps, pressure, water conditions, ambient temps it all changes the tune on the fly all the time.
Once very close I would limit the compensation to 10%. if the o2 took a $hit the tune wouldn`t change drastically. I never had any o2 issues however.
That being said I built 'garbage motors' so I wouldn`t take my advice, seems like you have it under control, if it runs great that`s all that matters.
shifting is the hardest thing to tune as are cold starts.
But again I`m just some dildo trying to play engine builder and most of the time it didn`t work out for me.

Dan,

The whole point for the Holley for me was an alternative to the 555 that could be tuned in a moment's notice (proverbially). When I was speaking with Mark Boos about the prospects of tuning the 555 (we were talking about changing cams at the time), he indicated that there would be at least two round trips for the ECM, shipping it to him, him adjusting the tune and sending it back for me to test and build an AFR table, then shipping it back to him for refinement. Farq that. The Holley eliminated all that and the tuning was done in a day. It fires up cold with a roar, just like it did with the 555 and idles stably at ~700RPM, even cold, even at zero throttle position, just like the 555 did. I'm happy as a pig in sh!t. I've got my boat back, and I don't have to worry about those damned wet biscuit cast pistons or PM rods anymore. It would appear that any/all the measures we did to gain some muscle might have been for naught, but it's all good. I'm on the water again.

Personally, I think the engines you built are badass, and I've shown pics and videos of them to many people.

Thanks. Brad.