Decarb question

Like this site very helpful, I have a question about the decarbing that is mentioned often here. I have a 86 Johnson 15hp. that runs very well, after reading about the decarb process I have a few questions. Since my motor seems to run so well is a decarb in order? I'm guessing decarbing should be done only when needed? I have noticed Seafoam has changed its formula to work better with ethanol, does it make any difference when decarbing? I have also been told to use gas that has no ethanol for me that means a gas with a 91 octane is this still the way to go when buying gas used for the outboard? Thanks for the help guys. Oh and to my knowledge this 15hp. has never been decarbed anything for me to worry about? Again thanks for any advice

Re: Decarb question

I'd say if it ain't broke don't fix it. If she's running good leave her be. On the other hand, a decarb almost never hurts and can only help. Seafoam is a great product and I would just follow the directions on the can when in doubt. I don't know that you need to use 91 octane either. Most folks run 87 octane (midgrade) without trouble. There are many threads and vids online showing various decarb methods, but I've had good success with spraying the seafoam directly into the carb throat during med-high idle. The motor will temporarily bog down a bit, you may have to give it some throttle to keep it running, and she'll smoke like crazy (seriously!), but that's sort of the point. That's all the old carbon burning off and coming out of the exhaust. I usually do that 4-5 times with a 4-5 second spray each time. I then shut the motor off and let it sit for 15-20 min and fire it up again. It's best if you're on the water so you can open her up all the way, but if not just run her in a tank at a brisk idle for 10 min, or until all of the excess smoking is finished. That may not be the by the book method, but it's worked great for me. You should notice your motor running smoother and quieter afterwards and many folks notice a much lower idle. Hope that helps. Good luck.

Re: Decarb question

http://forums.iboats.com/showthread.php?p=2648076#post2648076
Have a look at this from the Top Secret File at the beginning of this forum. I made myself a little gas tank (about a one quart bottle) as to decarb a small motor they just don't consume enough gas for the mix rate given. I've found that motors don't seem to carbon up as bad if normally they are driven in the upper end of their rpm range. On motors that I troll a lot with they have a lot more carbon deposit. Once I decarbed a 4 HP and was surprised at how little smoke it produced. A couple of weeks later I checked the compression and it had gone up close to 15lbs. a cylinder. TD said it must have freed up the rings even though there was little to no carbon. I think debarbing is a good thing to do but it is up to you. Best of luck. Rick.

Re: Decarb question

Thanks for the info, I'd like to use a mid-grade fuel but all that I've found have ethanol in them! Do most folks use seafoam regularly in there fuel mix?

Re: Decarb question

I use a product called Marine Stabil in every tank of fuel. Even if I think I'm going to burn it within the next day or two. As fall starts to approach I mix smaller batches of fuel so I don't end up with six gallons at the end of the season. What I don't use in the boat season goes in my vehicle, snow blower or what ever. Start each season with new gas. I really don't worry all that much about ethanol. I would be far more concerned with an internal tank that held 15+ gallons. Rick.

Re: Decarb question

Decarb should be part of routine maintenance in my humble opinion

Re: Decarb question

Thanks for the info on decarbing!!

Re: Decarb question

No prob. As I'm sure you've seen, there are lots of different methods to dcarb. I would say that Seafoam and Sta-bil are the two most common products, partially because they're so readily available and really do work well. It's gonna be hard not to find gas with ethanol in it these days. If you're lucky you might have a marina near by that sells ethanol free gas, but they're getting harder to find. They do make additives that supposedly offset the effects of ethanol, but I've never trued them. I think you might just have to resign yourself to it. That may mean shangin the fuel lines every few years, but it shouldn't do much more than that. Keep us posted on the decarb. Good luck.