Why all the "De-carb" talk???

[Cortes165]

This might be a dumb question, but I see people talking about this all the time. This is the first year i have owned my "own" boat so I'm just learning what should be done. Now I have snowmobiled for 20 years and have never heard of anyone "de-carbing" their sled engine. A 2 stroke is a 2 stroke??? I have taken my sled engines apart after 5 years of running and carbon is never a factor. Is it because outboards operate between 3-5000 rpm where a sled is a lot higher??? Just curious. Please educate me.

 

[Dhadley]

Re: Why all the "De-carb" talk???

Actually you have it pretty much figured out. While a sled or bike can have the correct gearing from the factory so the motor is never lugged, an outboard isnt like that. Propping it out correctly is part of the initial set up.<br /><br />Setting a modern 2 stroke up to top out at 5000 will cause coking (carbon) rather quickly with todays fuel. Set the same motor up to top out near 6000 and the coking will take longer to form, if ever.<br /><br />Not a dumb question at all!

 

[Stumpknocker]

Re: Why all the "De-carb" talk???

Nope, I learned something too. I have never de-carbed my engine either. Guess the setup really sets the stage.

 

[JB]

Re: Why all the "De-carb" talk???

Forty to fifty years ago we decarbed our small 2 stroke outboards and chainsaws regularly.<br /><br />We used 30W non-detergent motor oil at 16:1 and 24:1 ratios and we ran the engines at low rpm most of the time. Carbon was an ever-present threat to stick and break rings. . .or worse.<br /><br />Not only did we not have the great TC-W3 oils, there was no solvent based preparation on the market to decarbon the engines.<br /><br />We cranked the engines, got them hot, ran them to about 2,000rpm and sprayed small amounts of water into the carb with a spray bottle. The cylinder, head and piston got steam cleaned. After the white smoke let up, we ran them for another 5-10 minutes to cook off the last molecules of water.<br /><br />If we didn't do this we had to tear the engines down after as little as 50 hours.<br /><br />Even with todays oils and mixes decarbing is one key to long engine life. It never does any harm, and usually does a lot of good.

 

[Cortes165]

Re: Why all the "De-carb" talk???

thanks for info. You know the old saying, "I learned something new today".

 

[james roach]

Re: Why all the "De-carb" talk???

Because it is the number 1 killer of 2 stroke outboards.

 

[daveswaves]

Re: Why all the "De-carb" talk???

JB, we used to decarb our 38 Studebaker that way too, rev it up to 2000 and pour water into the carb. lumps bumps and bevel edged pieces usually blew out the back. Thanks for the memories!

 

[peeterb]

Re: Why all the "De-carb" talk???

When I was about ten I used to have to push on the gas peddle of my dads old truck while he poured water into the carb.I always thought he was nuts.I never thought about it till now.<br /><br />Glass

 

[minocqa]

Re: Why all the "De-carb" talk???

hi<br />i have question i'm going to rebuild my carburetors on my 1976 70 hp johnson<br />my engine has never been decarbed either should i do it before i rebuild the carb's or doe sit matter i just dont want to rebuild them and then gum them up right away when i decarb you know what i'm sayin? Plus how often should i decarb my motor it after that, is that something i should do seasonally? <br />thanks<br />Don<br />thanks<br />Don

 

[minocqa]

Re: Why all the "De-carb" talk???

thanks Middleground<br />i just wasnt sure if i should do it before or after rebuilding the carb's.<br />also should i do this in the lake or on the muffs?<br />thanks again<br />Don

 

[Scuda11]

Re: Why all the "De-carb" talk???

I'll toss my 2 cents in here. Did my last one on the muffs, in the driveway. Needed it real bad and man I am glad I did it at home and not on the lake, serious ka-ka as the Chief put it!<br /><br />However, being the time of year it is, less lake trfc, etc, I plan on doing it this week (weekday) on my lake, so I can do some WOT after a few minutes. <br /><br />Good luck.

 

[Cortes165]

Re: Why all the "De-carb" talk???

I'm not Mr. Enviroment but I do watch what I'm doing to keep things green. I read something here that is sort of ironic since we all go boating because we like the outdoors. Some people are saying when you de-carb an engine, you should not do it at home. Makes a big mess of your yard and/or driveway. But it's perfectly ok to perform this in the lake, and let all the oil and carbon crud to fly out of the exhaust ports. Just my 2cents.