What do these Spark Plugs say??
 

Have been having issues with excessive soot and a minor mis while under heavy load. Boat still runs excellent once up on plane and has no issue reaching it's peak RPM and speed. I have been thinking my issue is with Fuel Injectors. Had a guy tell me it also puffed a small bit of smoke when the mis was present. I ran a cuple of bottle of FI cleaner through it and the soot does seem to be clearing up. I changed the plugs Friday and it also feels like the mis may have gone away.

These plugs have been in for about one season. They are in order the way they were in the motor (if looking a it from back seat). I took 2 pics, one of the cleanest side of each plug and then flipped them over to get the dirtiest side of the plug. Looks like the dirty side was the side exposed to the fuel injector?? Anyway, what do these plugs say to you engine experts?? The lighting appears to have been bad in the photos, they are not nearly as dark as they appear in photo.... Engine is 496 mag (non-ho).

http://www.bradzgarage.com/velocity/plugs1.jpg

http://www.bradzgarage.com/velocity/plugs2.jpg

Need to cut the threaded portion off so we can see the base of the porcelain

I can do that... But how would I do that? Never really cut one before. Just a cut off wheel at the base of the threads (obviously cutting around and not through...)?

From my (admittedly scant) experience, the plugs won't tell you much. Since the boat has been run at idle, part throttle, maybe even WOT at different times over the course of a season, you won't be able to tell much other than early signs of detonation, which would be exhibited by flecks of aluminum on the porcelain, melted electrodes, etc. None of that is obvious in the pictures. Plug readings have to be done with a full or part throttle run on a new plug with immediate shutdown - don't let it return to idle for any length of time. As red posted, the coloration ring would then be found at the base of the porcelain. There are people who have been reading plugs for many years who will tell you that it is an imperfect science, especially with the ethanol and oxygenators in today's fuel.

If this is an EFI motor wouldn't you expect some codes to be thrown by the ECU if you are having a misfire or injector problems?

The plugs say its running rich, but all merc engines are set up rich. I haven't seen plugs from any other 496's to tell if those are darker than normal.

It is definatley rich, as evident by the soot on the transom.... I guess I am hoping some one can magically say "looks like a bad injector in cylinder #"... I know that isn't the case, but would be nice. I think I will pull the plugs on Friday (ran it one day on new plugs) and look at them. See how things look. I am really hoping it was a dirty injector, but things are never that easy...

+1 on this. No lead gas and now ethanol make plug readings very difficult. And to do it correctly you need new or freshly cleaned plugs, run at the condition you are trying to evaluate, then chop the ignition and pull the plug to look at it. Tough to do on a boat. Having said that mine look just about like this (496 Mag also) when I pull them out.

It does look like a couple of them could have an excessive gap. Measure that and set to the Raylar recommended 0.050 gap (stock is 0.055).

Dan

I put all new ones in at .050. I will check the gap on the old ones tonight.

Looks like you burn premimum...

90 octane free, that's what is at the docks. But it was actually tuned by whipple to run 93. But because it runs so rich, I haven't run 93 in a long time.

I would suggest you call Whipple and get some guidance. The plugs look reasonable but the soot on the transom says rich and new plugs aren't going to change rich.

I would tell you to check thermostat, but with whipple what is cold start temp set at in program. those are what normally aspirated fail-open t-stat looks like that I worked on.

If this motor is in your "03 you have listed in your avatar. They had a "not so talked about" recall on incorrect pushrods in the mag. motors "mostly". I think mercury put a white paint spot on the back, top side of the heat exchanger to let you know the motor had the new upgraded pushrods. Dont quote me exactly on the color of the paint, But read it somewhere before. Have done a couple just here recently that have broke off the ball on the end of the pushrods and the operator didnt really know they had a problem for a while (months). One had the same symtoms you are talking about. If you do have this DONT buy the merc. pushrods !! Way too expensive you can get them through any auto parts store from speedpro $70 a set. Merc. is $200+ Good Luck Just a heads up, hope that is not wrong with yours !!

Well if your ECU mapping is for 93, and your running 90. There is a good chance you could be seeing knock. Ecu pulls timing which results in a rich condition.

First think first is to remove the 90 and Put 93 Octane in like your mapped for before you do damage.

With 93 the soot was 2x as much. We do not run it hard at all and seldom in temps over 85-87 here in MI. it has a 120 T-Stat as recommended by whipple, which may be contributing to the last bit of soot i now see. t is run at less than 1/2 throttle... The push rods are interesting. Also I am aware that changing spark plugs won't fix the condition. I had suspected fuel injectors being the problem so I ran FI cleaner through it, then changed plugs to see what I end up with. The soot has gone WAY down. Almost not there, but still present. What is there now may be normal for the 496.... As I haven't really heard of anyone who has zero soot with that motor. I will do a plug check again this week. As far as bad push rods, since the mis has cleared up with the FI cleaner, I have to assume the pushrods are ok, but yes, my motor is an 03.

My 496 MAG was built in Sept. 2003. The only time you will see a really, really faint hint of soot on the transom is if I run in cold temps early or late in the year. There is never a hint of soot anywhere during the normal boating season.

here another thing to think about ,,you had Dustin at Whipple recalibrate your original ecu with a stage2 program ,,that program is meant to run on a 496 mag HO engine 425 hp,,if I am not mistaking you have a 496mag 375 hp engine,,you need to have the ecu reprogramed with the latest cal for a 496 mag with latest anti soot calabrations and start running 87 octane like its programed to do..

I put my ear up to the screen and I could not hear anything your plugs said, fail!

I agree with giving Dustin a call with the serial numbers off your computers to see what set up it was calibrated for. Ask which plugs, thermostat and octane fuel to run.
Also if you are using an oiled style air filter/arrestor make sure you clean it with the cleaning kit once a season.
BTW, I like the NGK plugs better.

I spoke with Dustin in great detail before sending him the PCM. I am pretty sure he flashed it with a Stage 2 program designed for the 496 Mag (non-HO). But I will certainly follow up with him again to be sure. I will say this, the motor runs a whole lot stronger after the Whipple Stage 2 flash. If it was a choice between light soot (now) w/Stage 2 or No Soot and go back to Stock PCM Flash, I will choose the Stage 2 every time. Even though the soot is a pain in the ass, the boat has so much more low-mid-range torque now. No way I would go back.... (This is the 3rd season with the Stage 2 Flash).

all right then ,,leave it alone and use it,,you have been going round and round with this for a while now,,


the stage 2 is a upgrade to the HO program not the Mag..you have the wrong cal in there,,to make it run right you need to install a HO cam and drill out you throttle plate idle bleed hole from 3/16 to 1/4,and the stage 2 requires and different thermostat,but if you like it then leave it and dont worry about what the plugs look like..
been doing this a long time and have been round and round this issue,,

Boatnt that is incorrect information. Whipple has a Stage II flash for both Base and HO PCMs. See below for the email discussin between myself and Dustins this morning..

My email:
"My name is Bradley Lynn and a few seasons ago you did a stage II flash on a PCM for a 496 Mag for me. I originally had you do this because I had a lot of soot and wasn't certain of timeframe Mercury had given me. Anyway, after talking with you we ended up going with stage II flash. You mentioned I would see some soot still as it was tuned for premium fuels. Well I have still been fighting a lot of soot. One of the issues was a leaky intake gasket that was pulling oil in under high vacuum. Once I fixed the gasket I still saw a decent amount of soot, but not greasy as it had been. It appears that may have led to dirty injectors, which I think I have gotten straightened out. I now still see a little bit of soot, enough so that I have only been running 90 octane ethanol free, which does cut down on the soot a bit. Since I don't run hard, I don't think I am damaging it by running 90, am I?. Anyway it was mentioned in a thread I have someone thought the Stage II flash was only for the 496 Mag HO. I have a 375hp 496 Mag Non-HO. Is there a way for you to verify the flash that was put on my PCM is correct for the Non-HO motor. It runs so good I assume it is correct, but I guess it couldn't hurt to check. DO you need the serial number or can you look it up by my name? Also can you confirm the fuel and plugs it was calibrated for? Pretty sure you said 91 or 92 Octane... Any help you can lend would greatly be appreciated."

Dustins Reponse:
"Thank you for the info. 90 octane will work under most conditions, 91 is better but most of our 91 has 10% ethanol and run hotter in the combustion. The 90 octane should have no issues.

We have cals for both the Base and HO models. I don’t have your PCM flash serial number or date, but if it came as a Base, it would be a base. The motors, with the wrong file, run just awful."

If I had a HO Stage 2 flash on a base motor, and Dustin says they run awful, I doubt I would be seeing GPS speeds in excess of 70........ Which I have done a few times this year. So there is a Stage II flash for the 496 Mag Base Engine, and it is what I had Dustin put on it. I am also running a stage II 120 T-Stat as what was purchased when Dustin Flashed My PCM. So I am confident the PCM can be ruled out at this point.

Your right I have, and the problem still exists..... That's why I am posting in hopes someone else has an idea... The PCM is correct, Doesn't show any faults, yet runs rich beyond what it should. I have addressed Flame Arrestor, Intake Gasket (which was at fault for the greasy soot, no longer an issue) and yet I still have a problem. So I posted a pic of the plugs in hopes someone might notice something outside of the obvious, like maybe one plug lookes a little different (maybe narrowing down the search to a side of the engine or even a cylinder or two that looks like it is firing a bit different). I have done compression checks and leak downs and all are well within spec, again boat can run full RPM and expected Top Speeds without issue.

firing issue (weak)....i just went thru this on my boat....for me i changed distributor and it fixed the problem

496 uses a crank and cam sensor and 8 coils no distributor

ok,,if you say so....

I didn't say so... Dustin @ Whipple did. So I will go with his knowledge of his product/work...

as Boatnt said, the 496 is distrubitorless.. It has a 1 coil per cylinder. I wish there was something that stood out like one really bad plug, then I could pursue maybe a bad wire, or bad coil. Thats why I posted the picture of the plugs, hoping something would stand out to the experts that maybe the normal untrained eye didn't see...

i understand it has no distributor. im only saying that the exact thing happen to me and the plugs look identical to yours and it was my distributor. i chased it for 2 months.

So after another half tank of fuel and another 2 bottles of FI Cleaner, the soot issue is all but gone. I ran 10% Ethanol in it Friday, which I know contributes to the soot a bit, and after a good solid run had less soot than ever. So I think running Ethanol free and a few more runs to clean it out and it should be like any other 496, soot free.... and it seems to be stronger than ever in the mid-range (which it was never a slouch). Haven't checked my plugs, but really don't see the need to at this point. :thankyouthankyou:

cool.... thats a cheap fix!