Re: benefits of decarb?
Opinons vary, but the general concenus is that there is a benefit from removing the carbon from the motor (hence, the reason such products for that specific application are available from the outboard manufacturers and others as well).<br /><br />It's not just that the build up carbon comes out of the exhaust...more importantly, it's where that carbon is coming from in the first place...obviously, a nice new clean running engine, mostly used at higher RPM's should in theory be cleaner to start w/, and buildup might be negligable.<br /><br />But, figure where the carbon comes from, mostly either at the top of the pistons, or the face of the associated head, or from within the grooves that the rings ride in...removing the buildup allows these parts to work as theyre supposed to. When you free up the ring a bit, should carbon be building, it'll seal better, perhaps improve the compression, and reduce the risk of potential for breakage in extreme cases. Also, heavy carbon deposits, act sort of like a glowing charcoal inside any combustion engine. What this means, is rather than having the firing of the spark plug be the primary source of igniting the fuel, the residual glowing carbon could very well set off pre-ignition and cause the explosion inside the chamber at a time its not supposed to...and bad things can happen, knocks at best, heavy damage and uselss pistons or more at worse.<br /><br />It would seem, like anything else, a well maintained motor will run better and last longer...so, over time (or especially when re-awakening a sleeping outboard) it's a good practice to follow.<br /><br />In any case, it's a simple enough, very cost effective way, to check one more maintenance item off the list that just very well may lead to noticeable improvements in the running of the motor (especially at lower RPMs).<br /><br />I too, was initially skeptical about how much could be gained from the practice...but figure, if you do it, using something like SeaFoam, and you get the black gook out...you know it had to come from somewhere, as it's a natural by-product of combustion, and keeping the insides clear of carbon is better than worse, for sure.<br /><br />It's kind of one of those yearly or bi-annual tasks, like impeller replacement.<br /><br />I'd vote for doing it, as I know it definately helped improve the low idle on my motor, and I'd swear it smokes less now (after the initial wave of burn-off). $6 or so a can for Sea-Foam, worth a try to see if it works, at least you can rest a bit easier knowing you did what you could to help clean the motor (and that goes for any motor that's been around for a while, boat, car, lawnmower or otherwise...you don't need carbon buildup in the combustion chamber or it's components).
