Ethanol + Seafoam will kill your outboard!!
I felt it was proper that I relate a recent problem I had. Since there is much debate about Ethanol in gasoline both good/bad. And while I have been a proponent of enhanced fuels maybe it's time I re-evaluated my opinion.
I just returned from a fishing trip in Northern Ontario. I took my 14' boat fitted with my 1991, 15 horse Mercury/Mariner 2 stroke outboard up with me. The motor had never given me any trouble in the 14 years I have owned it and has never seen anything other than regularly scheduled maintenance (according to Merc guidelines), which I do myself.
Since I have owned it (and like my two other small outboards) I run a TinyTach with hour meter. My very first issue occured just at the 2200 hour mark (don't know what the hours were on the motor which was 6+ years old when I got it - but safe to add a hundred or two for sure).
The motor started fine and idled at the launch. It did a full throttle run for the 7 miles down the lake to the spot where we were setting up camp for the week. When I throttled down, it let out a helacious "sneeze", the rpms slowly dropped and she stalled dripping raw gas from the lower cowl. Removing the hood revealed all the signs and symptoms of a blown crank seal - no doubt about it, I have seen it before, just not on the little Merc's. That really sucks when you are 800 miles north of home and almost 200 miles (half of it dirt road) from the nearest Merc dealer.
Anyhow, the week wasn't lost. As long as you gave it a touch of throttle it would run fine - but the gas mileage probably sucked running on about a cylinder and a half. On Sunday past I pulled the flywheel, removed the ignition and saw the seal - it was definately defective
The seal puller plucked it out an it was quickly replaced with a new seal (20 bucks, can you believe it - seals for my Evinrudes go for under $5 - oh well). I put her all back together and it's running like it always has, nice and smooth once again.
That got me thinking though, what could have caused it - hmmmm. I have been running ethanol in it since I got it. E-10 the first 11 years and E-15 for the past three. Maybe it was a cumulative effect....
WARNING - After running ethanol enhanced gas at rates of 10% or greater for 14 years you will destroy the upper crank seals in 25 horse and under Merc 2 strokes.... OR
Maybe it was the combination of E-15 and Seafoam. In the U.S. you guys/gals are well familiar with Seafoam. It only became widely available here in Canada in the past few months (now carried by Walmart Canada and Canadian tire). I had occassionally "smuggled" some accross the border but this is the first time I can clearly remember using it with my 15 horse.
That must be the lethal combination. After all, the motor is 20 years old and until this mishap it had never had any repairs done to it - never pulled and cleaned the carb, much less a rebuild. No ignition troubles, leaky lower unit, chewed gears, never stalled, hiccup'd or burped before.
So trust me when I say this (I now know from first hand experience) - NEVER mix Seafoam and Ethanol gas - even if your 20 year old motor has never had a problem ever in it's life, the lethal combination will EAT the upper crank seal right out of your powerhead
I'm now starting to think about selling her and getting a nice new 4 stroke - they NEVER give you problems like this....
(and if anyone is confused, the last statement really is sarcasm
A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)