Thread: "Decarb" Question

Scrapper, et al,
I see you guy's talking about doing a "decarb", as I stated in a different thread I have a 1982 Johnson 60 hp, I now add carbon guard to the fuel each time I fill up; however, I really only started this practice about a year ago so I would suspect that there is the potential for significant carbon build up given the age of this motor.

Ok, so my question is: what is the best method for performing a "decarb"?

Oh, one other thing. I also have a 90 hp Merc on my pontoon, rather than purchasing Johnson/E-rude 2 cycle oil and Merc oil I am using Merc/Quicksilver TCW-3 "premium" oil for both motors---is there any reason that I should not use Merc 2 cycle oil in the Johnson??

Thanks in advance.

Howard V.

Oops---I think I found answers to both @ the "iboats" FAQ page. Sorry.

Hey Rap, that Merc/Quicksilver TCW-3 "premium" is good oil and you can use it in any outboard. Any name brand oil rated for TCW-3 will work but like you I've always used the same that you do. In those directions for doing a decarb they warn you about the mess it makes. They are not exaggerating!!

Thanks for the info Bill!:D

Originally Posted by IBNFSHN

Hey Rap, that Merc/Quicksilver TCW-3 "premium" is good oil and you can use it in any outboard. Any name brand oil rated for TCW-3 will work but like you I've always used the same that you do. In those directions for doing a decarb they warn you about the mess it makes. They are not exaggerating!!

Yeah, the iboats forum is one of the best I've found for outboard information...VERY informative and LOTS of knowledge there.

As for your oil Ibnfshn is right...you may also notice that there is a premium and a premium plus...the plus also has a carbon guard/seafoam/ring free type additive already in it. That way you are not supposed to have to add any additive to your fuel. The plus used to be at Walmart..I have not been able to find it as of late.

I use the XD30 in my ol' gt150...the xd50 and xd100 have additives in them xd100 being a full synthetic I believe.

There have been countless threads on the different oils which ones to use and which ones not to. If I can find the list I'll post it. There is a list of all the oils that are cetified by the NMMA...as of last year "i believe" penzzoil was taken off of this list. I'll see if I can find this tommorrow. Very neat read. One is done every year. As long as you see the TC-W3 and the NMMA symbols you are good to go. Any manufacture brand oil ie...johnnyrude, merc, quicksilver, yammie, will be.

Like Ibnfshn said...it WILL make a mess...but is WELL worth it. Just dont' be on the nice clean driveway...lol.

Thanks Scrapper!

Scrapper, Et Al,

I have printed the instructions for "decarbing" using the "SeaFoam" in 3/4 gallon of gas. The motor I want to "decarb" is a 1982 model and as I said earlier it has never been "decarbed" and only been using "carbon guard" for about a year.

Is there any danger that large junks could be broken free in the combustion chamber and cause the piston rings to "stick"? Am I going to do more harm than good? I am a little nervous about "messing" with something that currently isn't giving me problems.

Please help---I am unsure what to do.

Thanks,
Howard V.

Rapp, I really doubt you'll have any trouble. If you are running at the mid to upper end of your rpm range (not lugging)...and have been running carbon guard you'll be fine. Just for peace of mind...get some deep creep or somemore seafoam in a spray bottle...have engine good and warm...tilt it up to its uppermost...pull spark plugs...spray a GOOD amount in each cylinder...replace plugs...let it set overnight...preferably the night before you go out. That will soften up anything before you go out the next day to do the decarb. Don't be embarrassed at ramp though...IT WILL SMOKE ALOT!!! But should clear up after a bit...then go out and do your decarb. Should be fine. Good luck, and let us know if you need anything else.

I ain't gonna swear to anything but if you've been running Carbon Guard for a year then it'll probably be fine to just do a decarb without worry of big chunks coming out. That shoulda took care of the worst of it. Not sure about using Sea Foam for a decarb because I always use BRP Engine Tuner and it works good. I put it in at the ramp with the boat on the trailer, let it sit overnight and then go back the next day and run the crap out of it. Then go home and change the plugs.

Why do we change the plugs after a decarb. They look like brand new after that?

Dayton