As a outboard dealer and 5 star gold certified service center we see a great many outboards with preventable fuel related issues.
Probably the number one most preventable running/starting issue is from not running your small carbureted outboard out of gas when you are done using it. Leaving the carburetor bowl full of fuel to evaporate each time leaves heavy solids behind that eventually cause a “varnish” or “sludge” issue the will surely cause starting and running issues. We see this day in and day out here at the shop, the customer always swears they’ve done everything right and it’s the outboard manufacturer who’s at fault. WRONG! Guess again sailor! When our certified mechanic gets into the system it’s almost always fuel residue and deposits. This failure modality is preventable and if suffered, treatable by a complete disassembly of the inflicted carburetor, and subsequent ultrasonic cleaning in special solvent. You better figure $150+ a carb to get it done properly and remember to do your job running it out of fuel before you put it away for awhile.
The second most common fuel related problem we see is carbon deposits from using the wrong octane fuel. There is no doubt that ethanol in our fuels serves no purpose other than line the pockets of our elected government officials and those of the industries which manufacture and promote this fake science. Testing clearly shows you get better cleaner burns in fuels without ethanol and better gas mileage to boot. Too many well intentioned but poorly informed people have thrust the ethanol economy on us and unless it’s voted down it will be with us for a long time. People trying to escape the hygroscopic tendencies of ethanol will proudly state that they buy ethanol free fuel from the fuel dock and think they are good to go. We hear it all the time at the shop, try telling someone they are wrecking that new motor with the wrong octane and they will tell you that the high octane gives them more power. I guess I missed this in physics and chemistry class but hey what do I know? We all know a sea lawyer or two, you know they guy who knows everything about boats and the water but has no “Time On The Pond”. Our advice on octane is to run the recommended rating for your motor by the manufacturer, which in most cases is 87 octane. This will be debated by sea lawyers until the sun burns it’s self out but a quick look on the subject to Yamaha’s tech pages confirms this number. The real question then becomes why are you running 92, 94 or 108 octane av gas? Running this fuel requires a high compression motor to get it to burn correctly, you are not likely running a high compression small outboard motor for your inflatable or your trolling motor so you’re better off buying the cheaper e10 ethanol fuel and running it out of gas every time. If you know Mike here at IBC then you know he’s a proponent of not storing gas in that little remote fuel tank. His advice on the subject is to dump old gas in your car and burn it up. Old to him is a few weeks, but to most other people it’s measured in months to years. More on this later! So your trolling motor runs like crap and it’s making oil now (magic) and you only run the best most expensive ethanol free fuel available. Well you’re doing it wrong. That motor is clogged with carbon deposits, and you are getting fuel dilution in your oil. Run the proper octane, open the motor up once in awhile and get some rpms going to prevent this failure modality from occurring.
The third fuel related issue we see here is from storing fuel and mixing new fuel with old gross fuel. There are any number of fuel “stabilizers” on the market that make claims for long term storage that will outlast a zombie apocalypse. The short answer is “NO” don’t store fuel. By trying to store that three gallon tank full of fuel for a year or two then running it because you are cheap and lazy means you just clogged up that carb like in the first paragraph. Pour it out (dispose of properly) or don’t store it to begin with. By mixing bad gas and new gas you are just making more bad gas that will ultimately clog up the carb works and make your motor run poorly. You don’t pour new milk onto spoiled milk do you? Do you…..? Our season is short in the NW don’t make it even shorter and more complicated. Follow some good housekeeping rules about fuel and spend your time on the water having fun, not radioing for a tow.
Call us (503)235-2628 we don’t call ourselves experts, but some of our customers do.