I use both products in different machines.

For the outboard, use the Ringfree, its worth it.

It much stronger than Seafoam. Can you use it every other time, sure. It will work better everytime but if you stay on top of it, itll be fine. The % ratio is pretty good, 1oz per 10 gallons, so it does go pretty far. Its a whole lot cheaper and easier than pulling varnished up carbs, fuel pumps, etc, not counting down time..

I would also use some sort or fuel stabilizer as fuel tends to go stale within a month. Ringfree is NOT a fuel stabilizer..

Just as a side note, I have a 8 HP chipper /shredder I had to use about a month ago. It was idling and running fine when left last time. This time, it wouldn't idle down (W/O stalling) and had a misfire wide open (3,600 RPM). I had the machine running wide open for about 1.5 hours. Put in a strong dose of Seafoam, no change. Put in a strong dose of Ringfree. Sure as $hit, within 1/2 hour, no more misfires, idled back down again as normal. That's without touching anything else, (just busy feeding the machine branches, etc).

I have used Seafoam (straight dose) in a MC carb (dual carbs actually), dissolve and open up a clogged carb without ever pulling the carb/bowl, etc ( I was really surprised it worked as the carbs were BADLY clogged)

BTW, when I ran it in the shredder, that machine has a plastic tank, maybe 1 gallon, I put in at least a half ounce (5 gallons worth). Didn't bother the plastic, hasn't bothered the plastic Yamaha under cowl fuel filter housing either.

Ringfree is very good stuff...developed for Yamaha by the Oronite Additives Division of Chevron specifically to address prevention and/or removal of carbon on the rings and grooves, especially in 2 stroke outboards...used at specified dosages it's not that much more expensive than other additives....

Great Stuff.

FWIW my servicing dealer swears by Ring Free Plus and Starbrite StarTron fuel additive. He says 70% of his service work centers on fuel issues.

I've had similar experience to TownsendsFJR1300, on a Toro lawn mower (B&S engine). I have to refuel half way through my lawn, and previous to using Ring Free if I didn't restart it within minutes of refueling I'd have to wait nearly an hour before it would start again. Began using Ring Free and haven't had an issue since.

The past two years I've used an additional product from Starbrite, called "Easy to Store, Easy to Start." Instructions tell you to put it in your tank and run the engine for 10 minutes, prior to storing for the winter.

I can tell you that the past two years my outboard (2000 OX66 150HP) has started right up in spring, and runs with the winterized fuel no different than new fuel.

Jeff

For any of my gas engines I'm not using for awile (chain saw, chipper/shredder, pressure washer, etc), I use Seafoam in the top end.

Squirt a little into the combustion chamber with a syringe and spin over (not starting). Lubes the cylinder, head, top end.

If a single cylinder engine, I make sure its at TDC with the valves closed to keep out moist air.. The Seafoam will also loosen up some of the carbon while sitting there. It will smoke a bit on start up but goes away pretty quick.

It'll still usually start the first pull even with the Seafoam..

Second year with 98 175 Yamaha ,first year carbs need rebuilding but still had a slight drop mid range , first year Startron and valve tech fuel still had the hesitation , second year ringfree ,startron ,and valve tech hesitation is gone SOLD

If I knew about Ringfree years ago, I'd probably still have my Evinrude still hanging on my transom. (and saved $14,000)

When I traded the engine in and re-powered it, it had one cylinder cutting in and out on occasion. Actually, running it to the boat ramp ,to trailer it to the shop, it ran like a raped ape...

Excellent stuff, well worth the $ initially as you won't be at the shop with most fuel issues...