How often should I decarb?

[erosenwinkel]

Read a few postings on doing a decarb. I have a 1985 125hp (1258x5a). How many hours should I run the engine before doing a decarb? I run my engine approximately 40 hours per year, in freshwater. Very careful about the 50:1 mixture and I am pretty sure the carbs are adjusted right per the sticky. I have heard positives and negative regarding this procedure. Is there a preferred method, if so what is it? Thanks in advance, Eric

 

[Frank Acampora]

Re: How often should I decarb?

Never, unless your engine is exhibiting specific problems that it might help.

 

[erosenwinkel]

Re: How often should I decarb?

Makes things simple, thanks.

 

[erosenwinkel]

Re: How often should I decarb?

Alright, curiosity has gotten the best of me. I can't help but ask. What specific problems would, or could, be helped by decarbing an outboard. My understanding is that carbon can get built up in the cylinders and this can reduce compression. As long as everything is adjusted correctly, the goal is that carbon build up will not occur. I read a few posts and saw what looked like a mosquito sprayer video and I am just a little nosy.
Eric

 

[Frank Acampora]

Re: How often should I decarb?

Carbon build-up in the cylinders is not the problem. Carbon and varnish get into the ring grooves and "weld" the rings to them. When the piston contracts upon cooling it pulls the rings away from the cylinder walls and compression drops.

SO: low compression on all cylinders would be one reason to use Snake Oil.

However, some engines will do poorly and actually be damaged by decarbing when they show no running symptoms.

Modern TCW-3 oils are formulated to prevent carbon and varnish deposits and somtimes will actually help clean rings and cylinders.

SO: While some people swear by decarbon treatments and some swear at them, I take a more moderate view. While I jestingly call these treatments Snake Oils, they can occasionally have a use. I however would not use them regularly. I consider them a "Hail Mary" move and consider regular use of them a waste of money, like using high octane gas or oil additives or octane boosters or ignition boosters.

 

[erosenwinkel]

Re: How often should I decarb?

Thank you for the explanation. I'm new to boating, thus new to boat maintenance so any little nugget of information or advice is very much appreciated. Eric