496HO with Raylar kit and Whipple Stage 2
 

I know there are previous posts on this, but I just wanted to clarify before making changes to my motor. I have a 2002 496HO with Raylar's 103kit and Whipple's Stage 2 PCM Calibrations. Engine runs strong, but has serious transom soot, black oil, and strong fuel odor from exhaust. I run a low temp thermostat (runs 140-150 on guage) and use 91/92 octane. I heard to use 89 or less, tried that didn't help. I'm going to put the stock themostat back in this weekend to see if that helps. Is there any type of re-flash that can be done to the PCM that might also help? I know some degree of soot is common with 496's, but mine is terrible!
Ray, Dustin - help please!!

A "re-flash" for the computer is the only way you can help it. You can send the computer back to Whipple and tell them the syntoms so they can make a change in the fuel calibration.

Once you have Whipple calibrate your computer they put a password in it so only they can axcess it to change it. So you have to deal with Whipple now. Not a bad thing, just telling you. It may take a few tries but you need to do it!

That sounds like a cool motor (particularly for a 25OL). How many hours do you have so far?
What drive and prop are you running?

Take it easy until you get the PCM right. Unburnt fuel in the exhaust means you are taking the lube off the exhaust valves, and that isn´t good for them and is a sure sign that the settup isn´t right yet. Whipple will get that sorted, I´m sure, but talk to Ray about it, too!

Our stage cal is for stock motors. Raylar tested these cals with his packages and confirmed they do in fact work together. You might want to contact Ray because he has more data with the computers and his engines. For a custom tune, we'll need air fuel, rpm and manifold pressure data, no other way to do it. Our stage program already runs 14:1 at part throttle and 12.5:1 @ WOT on stock engines, not to mention a ton more timing everywhere, so not much can be done on stock engines, but with your engine, it might be possible to tweak.

Thanks for the reply, Dustin. I don't have the set-up to measure A/F ratios (wish I did). I read on another post that "Hot 4 Teacher" was having the same issues with an identical set-up (496, Raylar103, and whipple stage 2). He has all the gear to read his Air/Fuel, pressures etc and relayed the #'s back to you. He said it took a couple tries, but his engine is now running great and soot free. I guess every engine is different, so what works on one may not work on another? Do you think the CMI Sport Tubes I'm running could have any affect?.
I heard Raylar recommends keeping the stock thermstat when using his aluminum heads with the Stage 2 calibrations, I thought I would give that a try this weekend and see if it makes a difference. I pulled a few spark plugs and they looked good, not loaded up at all.
Any input is greatly appreciated.
Thanks,
Bruce

Thanks, Wild Card. I have 134 hours on the motor (about 80 hours since the Raylar kit was put on). It also has CMI Sport Tube headers - looks and sounds awesome. The previous owner had the modifications done over the last couple seasons (I bought the boat in March). He was very meticulous and took amazing care of it - it looks like brand new inside and out!
Right now I'm running a labbed 28p Bravo on a Bravo X leg. Best speed so far is 74.4 on GPS at 5100 rpm. I think there's a little more there - need to get this fuel/soot issue figured out first (don't want to hurt a good motor!)
Your 25OL is something else - how's the 600 treating you? Looks awesome in the bilge (seen pic's of it on other posts). My brother-in law has a 25OL with a blown 540. He's been hitting 88 with a Sportmaster and Stock 28p Bravo. I think he picked up a labbed 30p to try - tons of fun!!

Bruce, the only way you can get a custom tune is to provide the #'s Dustin mentioned. IMO, it's a good idea to monitor the A/F in an aftermarket motor and FASS makes it really simple. Your CMI's have O2 bungs, right? I wouldn't run 91, nor would I run 87...89 is where you need to be with a stock stat. I guess it matters how aggravating your soot problem really is. Mine was bad enough to get the right #'s and send it to Dustin a few times.

Good luck!!

Hi Hot 4 Teacher, I didn't notice any bungs on the headers - I'll check again. What rpm's did your motor produce the most soot at? It seems like mine is worst at idle and low rpm (under 3000), but maybe it just sticks to the transom easier at lower speeds. I ran a tank of 89 from Chevron (no Sunoco up here), on the long weekend but it didn't seem to help compared to Shell's 91. Hey, were you also seeing your oil turn black after only a few hours?
Your Crownline must haul a$$ with the Raylar 496 in it! I met a guy last summer that had a stock 496HO in a 22 foot Regal with the Fastrac hull - he was hitting 70+ no problem! Took a lot of bigger boats by surprise!
Bruce.

Just checked the headers and there are bungs on them (in the collector part of the headers - before where the water enters the exhaust) They already have something connected to them - Mercury's Smartcraft doesn't use O2 senors do they? There are two wires coming from them, looks like a pinkish beige wire and and dark brownish wire with a light stripe. They go up over the valve covers into a wire connector and then kind of disappear under the manifold cover.
Anyone have any ideas?
Thanks,
Bruce,

Sounds like you're already measuring A/F somewhere and I'm not familiar with smartcraft.

I produced the most soot @ idle & cruise speeds. (750 - 3,000rpm) I haven't really notice the oil turning dark either, I'd say the two problems are directly related though. I run Amsoil 20/50 racing oil, if it matters.

Believe it or not, my boat is a 550hp turd. I don't have dyno #'s, but it's been bored 30 over with all forged goodies too. The best I've seen is 68 mph with a light load. However, I've beaten a few "70+" boats with it. :D I keep it only because of all the room it has. I had 4 adults and 6 kids in it last weekend and it's still small enough to yank a skiier out of the water and plane @ less than 20mph for the youngin's watersports.

I know how you can go faster :)

Those might be the stock temp sensors. The bung size you need is 18mm. Mercury does not use 02 sensors except for the 2009 motors and some late 2008 engines.

Dustin you dirty dog.....stop teasing us!!!
mike:p

Me too.. lol :D :D Jamie / Lakeside

Raeburn:

Check your fuel pressure settings with a calibrated fuel pressure gauge and make sure they are not higher than 50psi key on, engine off. You might also try turning down the fuel pressure just a couple of pounds to lets say 48 psi and try that briefly to see if most of the overfueling that you see occuring disappears. As I have posted before, some of this black soot is from our new wonderful gasoline blends and not unburned fuel. Look at the tail pipes of most new GM vehicles and touch with your finger inside when cool and you will see the same black soot and these vehicles run very lean on closed loop O2 systems.
As for fast boats, "Want a really fast boat, then purchase a fast boat hull to begin with, Want a big, mass produced pleasure type hull then be happy with mid 70 mile per hour speeds" You won't see any race teams using performance pleasure hulls and equipment for racing!

Best Regards,
Ray @ Raylar

I put the stock thermostat back in and also a fresh set of spark plugs. The motor's running around 170* now. I'm a little chicken to run 89 octane in it with those temps so I used Shell's 91. It ran great, a little lower speed than earlier in the year, but it's a lot hotter out now too. There's still soot on the transom, but it's definately not a bad as before (it washed right off when I got home). I can still smell unburnt fuel in the exhaust when idling through no-wake zones if the wind is blowing the right way.
Raylar, I will check the fuel pressure first chance I get. I know the previous owner increased the pressure after putting your 103 kit on - maybe he turned it up too high. All in all the engine is running great - not a single glitch other than the soot, so I don't want to mess with it too much. Hey Raylar, did you do any dyno tests with your 103 kit and the Whipple Stage 2 calibrations? If so did you see any Air/Fuel or ignition timing issues in the calibrations for your higher compression heads?

Thanks, Bruce

Don't keep running it for too long with it being so rich at idel. If you smell u burnt fuel at idel, thats more than a little rich. You will hurt the engine.

Whats weird is there's the fuel smell in the exhaust, yet the spark plugs look perfectly normal. Is the high energy of the coil near plug set-up keeping the plugs clean even though the motor is over rich?

I had a 23 foot Wellcraft sport hull that I put a 525cu big block in (it dyno'd 600 hp, 601 ft/lbs - though probably closer to 540hp at the prop). Thought it was going to just fly - best I could ever get was 70mph - not bad, but I was expecting more. It's like Raylar said, if you want a fast boat buy a fast hull. Sport boats don't have hulls designed for high speeds and need a ton of power to go fast. It was fun having something different though - I bet a lot of those '70+' boats were surprised to see a Crownline bowrider spanking them!

So you know the pain I'm feeling. :D 70 is about as fast as this boat needs to go. The plan is to yank this engine and put it in my next boat. The current flavor is a Hallett 255, but you can't find one east of AZ.

Sorry Dustin, you'll have to wait until the engine changes homes for the supercharger. As you already know...the forged internals weren't done by accident. :cool-smiley-011:

I checked the fuel pressure today, it showed about 54 pounds with key on, engine off. With the engine idling it was fluttering between 54 and 60 pounds. Too high, so I go to adjust at the regulator (with #10 torx) and the screw head is stripped!! The screwdriver will grab but slips as soon as you put any torque on it. I don't know how much force it will take to turn the screw (I'm not familiar with stock GM MPI fuel regulators - there's no lock nut or anything - do you turn screw out to reduce pressure?)
Does anyone have advice on what to do with the stripped screw to make it work? I could probably replace the regulator, don't know how hard it would be, it's pretty buried under ECM, wiring etc.
Thanks,
Bruce

Are you using a tamper proof torx? Should not be to hard to turn it once all the paint is scrapped out of the way...A little trick is to drill a hole in the bracket the holds the computer then you can adjust it on the go....

Good call, we did the exact same thing!

I got a tamper-proof #10 torx, but the screw head was too stripped to turn, so I had to put on a new fuel pressure regulator. I dialed the pressure back to 49 pounds and ran it for a weekend poker run - really cleaned up the soot (still a bit there but nothing like before! The oil is staying cleaner too). I checked the spark plugs after some WOT runs and they looked okay - I find these long life platinum plugs harder to read than regular ones, they seem to stay pretty white even under overrich conditions.

We had some leakage around the head bolts for a few hours after we install the kit. We put plenty of sealent on the threads so we just made sure the bolts were tight and put some hours on the engine and sure enough the leaks stopped. I would monitor the leaking and enjoy the boat for the rest of the season if it was me.