I got one of these nice purring little gennies used, and now I need to know what to do with it!I have zero experience with small gas engines. Never had a gas lawnmower.I dumped the gas out of it and ran it dry, on the suggestion of a friend. Now, should I get special ethanol-free gas for it? Or can I use regular? I suppose it predates unleaded regular...?Should I add stabil? How much?What do I need to do in terms of ongoing maintenance? I think I can print out a manual, but I figure some of these aspects (like what fuel to run) will be outdated and I need to ask you guys. I did get a gardening knee mat to put under it, on the advice of somebody here (smkettner?) but I don't have a rear rack for it yet.

First things first.... put some regular fuel in it, run it for about 10 minutes, and then drain the engine oil and replace with some good synthetic 5w-30 motor oil in the crankcase. Not sure if it takes 1/4 qt or about a 1/2 qt per oil change. Oil needs to be hot, hot hot and mixed up/homogenized from running before draining out and replacing. Additives to fuel... Stabil should be in the fuel, 1 oz per gallon, or get a 6 pack of Chevron Techroline at Costco. Needed to keep the jets unclogged if you don't use the generator regularly. Read the label for mix ratio.

The if you can find itWhile give you the octane rating for the gasCurrent regular is around 82 octaneThat stuff did not exist when the ex650 was mfgI think 89 octane was regular then92 mid gradeNumbers might have been even higherI would buy premium, it doesn't use much, try to give it fuel / octane, it was design for

x2 on multigrade synthetic. I use sta-bil when storing gas in anything. If used regularly I don't bother. With my portable gens normally I just run all of the gas out of it and store it dry.Check the air filter.

Thanks, guys!Ninerbikes, Do unused Stabil and oil go bad? I think I have both sitting around, in jugs a couple years old. Or do I have to go to the store?Ductape, Is the air filter the fuzzy white stuff that lines the exhaust outlet, or something else? It is pretty clean, not perfect. Are you implying I can actually buy a new one? Should I?Mr Wizard, do you mean that unleaded is ok???

Here's a link to a manual:EX650YMMV, but I run ethanol-free fuel in all my small engines. Any fuel over a month old goes into one of my vehicles. I don't use a stabilizer but I run the carb dry at the end of the season and haven't had any issues.This spring I had to clean the carb on SIL's string trimmer. He let it sit all winter with a load of E10 in it.

Care and feeding of my ex650? | Good Sam Community

21 Replies

Naio
Explorer II
Aug 06, 2015
NinerBikes wrote:
So OP, how is your EX650 working out for you on a daily basis? Did you get the oil changed and replaced with the proper oil in the proper quantity? Clean out, wash and re oil the foam air filter too?

Aw, Niner, thanks for asking :).

My van has been in the shop for 2 weeks, getting some electrical mods. I left the genny in it, so have not had it around to mess with. No time anyway! But today or this weekend I hope to get to it, change the oil, clean the air filter, get some nice (or decent) gas. That's why I dug up this thread, to refresh my memory. What is up with shop guys who keep out rigs forever?

I am happy to have my van back, anyway!
jplante4
Explorer II
Jul 31, 2015
You can get 100 low lead at any small airport. Stuff has a 2 year shelf life with no additives. Price is around 5-6 bucks a gallon these days.

I work at an airport but don't bother with 100LL. I get <10% ethanol pump gas and put stabil or Lucas in the can when I get it.

However, I'll be south this winter so I'll fill the mower and snow blower with 100LL before I leave.
NinerBikes
Explorer
Jul 31, 2015
So OP, how is your EX650 working out for you on a daily basis? Did you get the oil changed and replaced with the proper oil in the proper quantity? Clean out, wash and re oil the foam air filter too?
jodeb720
Explorer
Jul 24, 2015
FWIW,

I inherited an ex800 from my father in law - it wasn't running - hadn't been run in years.

I dumped the old fuel, flushed the tank and cleaned out (rebuilt) the carburetor.

Changed the oil, cleaned the air filter (it's a foam filter)

That was 13 years ago. I gave that generator to my brother in law. Since then, he's never cleaned the air filter, never changed the oil, never dumps the gas.

All he does is shut the generator down at the end of his trip and puts it away for months at a time.

It's still running.

I don't know what honda did to make this carb setup so robust, but it's just awesome! If I did this to my EU2000, it wouldn't run right.

Maybe the vintage that it was built was to have more "slop" in the design specifications because things were known to be problematic.

Bulletproof!
Naio
Explorer II
Jul 24, 2015
Wow, you guys are awesome, thank you!
NinerBikes
Explorer
Jul 23, 2015
If you are running your generator regularly and burning up a tankful of E10 gas every week or two, then fuel stabilizer or additive is unnecessary. If you are not using it regularly or burning a full tank of fuel in it every month, then you do need the additives.

If you buy ethanol free gasoline, it's a non issue, for up to a year or two. Still better to run the generator 1x a month under some load, to keep the carb clean.
Tom_M1
Explorer
Jul 23, 2015
About 4 years ago both my Yamaha 1000 watt generator and my Kawasaki KLX250 motorcycle developed carburetor problems using E10 gas. I ran some SeaFoam through both and after that used only non-ethanol gas. Since then I have had no problems. Ethanol-free gas is also called non-oxygenated or recreational fuel.

Here's a link for stations selling non-ethanol gas:
Ethanol-free gas stations
pnichols
Explorer II
Jul 23, 2015
Naio,

I use whatever gas in my little EX650 ... and sometimes keep Stabil in it's gas storage can and sometimes not. It has never seemed to care much about the gas I use in it.

It was given to me back in the late 1980's in like-new condition and still looks and runs like new. I use the most expensive synthetic oil in it that I can find - Mobil 1 Extended Performance. I also use an E3 spark plug for a slightly less labored, smoother sound and longer run time per tank of fuel.

You can also use a shot of SeaFoam in it's tank once in awhile. :)
NinerBikes
Explorer
Jul 23, 2015
Naio wrote:
Thanks, guys!

Ninerbikes, Do unused Stabil and oil go bad? I think I have both sitting around, in jugs a couple years old. Or do I have to go to the store?

Ductape, Is the air filter the fuzzy white stuff that lines the exhaust outlet, or something else? It is pretty clean, not perfect. Are you implying I can actually buy a new one? Should I?

Mr Wizard, do you mean that unleaded is ok???

Shake oil up thoroughly, to mix up additives. Is it full synthetic and the proper oil weight/grade? You just bought a generator you are counting on to fill up your batteries daily, don't cut corners or a few bucks on motor oil, it is the lifeblood of that new to you generator.
Stabil keeps just fine, just make sure you put the cap on securely for storage.
westend
Explorer
Jul 23, 2015
Don't worry about the gas unless you are going to carry 5 gallons or more when using the generator. If you do carry that amount, mix the Stabil into the gas can. ISTR, the EX650 has a metal tank. If so keep the tank filled when stored. If it has a plastic tank, you can run it dry or keep it full, your choice.

Either E-10 gas is blended differently in different regions of the US or it is just bad on the West Coast. Here, in the Midwest, we've had it for years and nobody seeks any special gas for their small engines. For a few years, I maintained a fleet of small engines (*125) and all were stored for more than 6 mos. with E10 gas and Stabilizer. I didn't have any problems from the gas. During the six mos of summer use, all operated on E10 (no stabilizer) with no problem.