Small engine (5-25hp) fuel additives

Good morning. It?s almost spring but that?s kind or irrelevant. The fuel additive thread below got me thinking about the fuel used in these small engines.
I have about 15 -20 small engines Honda?s real red ones and a few blue, also a couple kohlers, Kawasaki and B&S. The fuel I get is probably mid grade... whatever we get delivers from the Co-Op and marked red for Ag use. Over all I don?t have too many fuel problems. I try to put add on plastic fuel filters in line wherever possible, as well as the big filter on the gravity tank.

My real question is, should we add anything to the fuel, at least in the fall after we slow down the use on some of them. Occasionally we will run out of gas and I grab a the chainsaw fuel 50:1, I never see them smoke and power is never an issue. Is that 2 cycle oil good for living the valves? Is there something else better we should use?
I do change a lot of spark plugs, but nothing is ever really fouled, they just get changed regardless... cheap insurance to keep the equipment running.
Anyway, what do you all uses for regular use and before storage.
Thanks, Grant

The only additive I use is Sea Foam, and then only when I sense a engine is not running quite perfect. I use E-10 in all my 4-stroke engines, but I do buy ethanol free premium for my 2 stroke engines, and we have about 10 of them. I always use 40-1 mixed gas for priming engines, but to use it for a prolonged run could cause some carbon buildup. I do run some mixed gas in the roto-tiller and snow blower before storage, because they sit for a long time.

No additives. I top all tanks off in fall to keep air at a minimum.
Then in spring I run all the gas out before fill again.

Throw away all mixed gas or burn it in old tractor,

Have read the others. I only use hi-test gas in all of my small engines. They are much happier. If you really want to be impressed, go look at my entry about IRIDIUM sparkplugs in the lawn tractor thread. Many small engines today use the same plug. I use NGK plugs. Most engines take the same plug so the number is BPR6ES. Go on Ebay and order a 4 plug box of BKR6EIX-11 /4272 IRIDIUM plugs. You will be astounded how nicely they work. Every Briggs and Honda I own has these.

Thanks guys. Good info.
I typically use NGK BPR5ES in everything except the gator engines (Kaw) they are a different number NGK, hotter I think and don?t run well without them.
I will get some iridium plugs and try.

I must say SeaFoam does work well. I had a very smoky 4 cylinder diesel Isuzu engine in our Morooka. I changed the fuel filters and filled them with SF as per the instructions. Primed and fired right up. Smooth running and no smoke. It must have cleaned the injectors a bit ... and everything else. Once the diesel came through it was noticeable but ran much better. Probably change the filters again and do it again.
Maybe worth adding to the small engine gas every now and then.

Thanks for the input.
Grant.

Yup...the 5 is just a little hotter and they say if you are running a 5 or 6hp engine that is the one. Don't know but I have always run the 6 heat range. Those IRIDIUM plugs will blow you away. Once your engine has a little warmth shut it off and start it again. You can't get your hand off the key fast enough cause it is already running. Instant starts. BAMM.

I have a 2002 Mercury 115 hp, 2+2, 2 stroke outboard. After putting premium gas and iridiums in my small mowers (along with my regularly added Sea Foam) after your suggestion worked so well I thought I'd try them in my outboard since the lower 2 cylinders don't generate power at low rpms and as a result the plugs, although firing, aren't causing the cylinders to come up to the temperature required to burn off contaminants on the plug insulators.

Pulled up my NGK catalog, and somewhere around page 268 (recollecting) I got into the "IX" (Iridium) plugs section and cross referenced my OEM recommended plugs to IX. In the process I decided to go to a hotter plug too so I dropped down from 8 to 6 on the heat range. I was already using 91 octane gasoline as fuel so I didn't need to change that....engine is rated for 87 octane minimum but with 20-22* BTDC at WOT, pre-ignition could be a problem anyway so I already had that addressed.

Water testing revealed starts faster than you could operate the key switch and contrary to reports of rough idling with these engines, with the engine tilted up slightly so that any un-ignited fuel wouldn't puddle in spark plug area, idling around in the no-wake zone and all, you could have placed a full glass of water on the engine and not spilled a drop.

I started running ethanol free recreational fuel in all my equipment I fill with gas cans 5 years ago. It's usually $1.00 a gallon more and I go thru 70 to 100 gallons a year. If the equipment is going to sit for an extended period of time, I add Seafoam to the last tank before shut down. I also add Seafoam to all my mixed gas just because. Have virtually eliminated all my carb issues (and I had a bunch of carb issues with 10% ethanol). For all the people who have no issues with regular gas, I sure wish I could get that lucky.