From boatsetup.com
Carbed Motor Decarbonize Procedure
By Rowdy
Updated 01/03/04
Required materials:
1. Engine Tuner Cleaner part# 771297
2. BMCA Fuel System Cleaner part# 772031
Optional materials (recommended):
1. BMCA Carbon Guard part# 772048
2. Oil tank filter screen part#174377
I use 1 spray can of Engine Tuner Cleaner for each cylinder (a V6 would get 6 cans). I recommend adding BMCA Fuel System Cleaner before starting the decarb treatment. Each bottle will treat from 12-20 gals. The 20 gal mix ratio would be for a routine treatment but we want to mix it to the 12 gal mix ratio, so buy how ever many bottles needed for your fuel capacity. If you have 24 gals of fuel on board at time of doing this, slug her with 2 bottles of the Fuel System Cleaner. Get that in there before you start the process and get it shook up well in the fuel by driving around the block towing the boat. This would also be a good time to start to use the BMCA Carbon Guard in the fuel to help keep the carbon from building so quickly. If you choose to, one bottle treats 96 gals of fuel, so mix it to how much fuel you have and then add as necessary when you refuel.
Oil is the next thing to consider. This would be a great time to start the use of the Ficht Ram oil as well if you have not done so. It has carb-X in it and is a better oil than the plain TCWIII oil. You should drain the oil tank and check it once a season for crud that could get into it anyway. It is easy enough to unhook it leaving the hoses attached, lift the tank up and pour it out. You might even change the filter screen in it as well. You will need to take the top out of tank with a torx driver and slip the nylon filter mess media off the suction tube. Then just put the tank back in boat and add new oil. It should still be primed as you should not drain hoses. Look all the hoses over though and replace them if needed.
Now that we have that all out of the way, as an annual routine I would:
1. Get a new fuel bulb as well. Make sure to get the right size for what HP motor you have. 2. I think this would be a good time to change the lower unit oil too.
3. Change water pump impeller if it’s been over two years since last replacement.
4. Pull the prop off, grease the splines and check for fishing line and get that all squared away.
5. Get a new set of plugs for the motor as well so that you can replace the old with new after you get through decarboning the motor.
Once you get on a routine of all this, I would try to decarbon her once every 75-100 hours if you use the Ram Oil and Carbon Guard. Every 50-65 hours if not. That will keep that under control.
We’re almost ready to start the decarbonizing. First, any spin on fuel filter in the fuel line should be removed, dumped, filled with Tuner Cleaner and reinstalled. Then pump the fuel bulb to get her ready to light off. Remove the hood and air box, hook motor up to a flusher on hose and get the motor warmed up to operating temp. With motor running, shake the first can well and hold the throttle bodies open enough to keep her running with one hand as you spray the tuner through each carb for about 15-20 seconds per carb. NOTE: If can(s) have a hose attached, cut off to about 3″ in length. DO NOT, in ANY CASE, attempt to inject cleaner through the Schraeder valve! This will need to be done as quickly as possible too, so that you leave as much chemical as possible in each cylinder. Just keep going from one to the next with the spray and keep the R’s up to 1800-2500. That will help pull the tuner down in the motor. Once the can is just about empty, let the motor start to load up somewhat and keep giving the carbs a shot from the can and let the motor load up and die if you can. If not, shut off the engine as quickly as possible and let soak for one hour.
While she soaks, take the hose and rinse off the drive way so as to keep it clean or the carbon will stain it somewhat for a while. The white smoke will leave you wondering what it will do to you as you had to breathe quite a bit of it. Well, you will glow in the dark for a while but not forever. I figure the perks would be that it kills Anthrax spores though LOL….
Start the motor one hour later and let warm up at a fast idle. About 1500 would do the trick. Once she gets all warmed you need to bounce the throttle a little to blast the loose carbon out of the engine. This is where it gets somewhat tricky to tell you how to do this as I don’t want any hang time here, so just punch the throttle and right back out of her. Bounce the throttle enough to get 4000-4500 R’s but no hang time there at all. Do this 4-5 times with some idle time (about 20 seconds) between each bouncing of the throttle. Get the second can of spray and repeat the treatment, letting the engine soak for one hour.
Repeat this for each can till the last one. For that one, I want to let it soak for over nite as this will be where you get the hardest to remove carbon off her. Once you get the last can in her and soaking, clean everything up good, put the air box and the hood on, leave her trimmed down all the way over nite. In the morning, make her ready for a lake trip and go run the hound out of her. I mean go run the lake WOT! This will finish getting the carbon out of her. Once you are happy with that, take her back home and install the new plugs. Put the new plugs in her while you are at the lake if you like, then go run her some more. Wouldn’t hurt anything.
While you were letting her soak between each treatment, you could have been changing the lower unit oil and all that stuff, but I like to do that before I start the decarbonizing. That way I can leave the motor tilted down all the time so that the chemical will run through the motor. This chemical works like oven cleaner, so doing this with a warm motor is best. While doing this though you can cleanup things on her as she soaks and make the most of it….Tackle boxes need to be cleaned once in a while anyway LOL….