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Mower engines and fuel type

Regular unleaded; that’s 87. Anything else is a waste of money.

@Bing mentions problems with really small fuel holes used in some carb-equipped small engines getting clogged. I’ve had this problem happen to me quite a few times w/my Sears Craftsman 3.5 HP 4-stroke push-type lawnmower engine. It’s easy to tell when it has happened. It won’t start no matter how may times you push the primer, or pull the rope. I use 87 octane and a fuel container w/a super fine sieve in the outlet for filling, so I think the solution for me is probably what Bing mentions, using specialty fuel and fuel conditioner.

The reason I don’t is that this problem only happens once in a while, and is very easy to fix. You don’t have to remove and/or disassemble the carb, so this takes maybe 5 minutes total. Use a combo wrench (8 mm) to unscrew the hollow brass bolt that screws into the carb fuel bowl from below. Pinch off the fuel line first. And don’t lose the bolt’s gasket. With as good of light as you can get, easiest in bright outdoor sunlight, maybe even use a magnifying glass, look very carefully at the shaft of the brass bolt, right where the threads stop. There’s a really tiny hole, almost impossible to see. That’s what clogs up and causes the no-start condition. A little Berryman’s B12 sprayed into that hole, then the other holes, make sure spray is freely emerging from that tiny hole. Then replacing the bolt, that will usually fix the no-start problem.

You can drain the tank but if you habitually run the carb dry, you are more prone to these kinds of problems.

And you’ll run into problems by NOT running it dry…like varnish. I’ve had carb varnish on me before. Remove carb…soak it in carb cleaning solution for 24 hours.

@GeorgeSanJose: How I always did it was to take a pair of pliers and pull off a brass wire from a “wire wheel” drill attachment. Then work it in the carb jet orifice to gouge out the schmutz. Soak 'er in carb cleaner for about an hour and re-install.

Better head this back to a auto centric discussion,dont like alcohol for cars-but if I could get pure alcohol for a pure alcohol designed small engine I might bite,because emissions seem to be better on a alcohol engine,have seen a string dimmer designed to use small bottles of propane.while the emissions picture seems better on a propane engine for cars-Kevin

Heres my take on it…

I have a 2003 honda mower that has been stored with gas in it every winter for 11 years, it always fires right up and runs perfectly. I have used whatever gas was easily available in it. No problems, I never use fuel stabilizers and probably have had ethanol gas in it.

I recently started buying 91 octane ethanol free fuel and running it in my 2 stroke equipment and my 4 stroke mantis tiller. Its hard to find ethanol free gas around here, and when you do find it its 91 octane.

My echo 2 strokes specify 89 octane fuel, I forget why this is.

“Better head this back to a auto centric discussion”

Thing is if it wasn’t for mower questions and GM ignition switches, there wouldn’t be much activity.

WheresRick, I never had any problems either until a few years ago then hit my mower and generator. I suppose it just depends on the batches of gas that are available from time to time but the quality of gas is not getting any better. The other thing is that the EPA is putting strict standards in place for small engines so the new ones have no carb adjustments whatsoever. They either work or they don’t and if those teeny tiny holes plug, they won’t work.

WheresRick, I never had any problems either until a few years ago then hit my mower and generator. I suppose it just depends on the batches of gas that are available from time to time but the quality of gas is not getting any better. The other thing is that the EPA is putting strict standards in place for small engines so the new ones have no carb adjustments whatsoever. They either work or they don't and if those teeny tiny holes plug, they won't work. </

I agree, I have a 2010 echo leaf blower and a 2013 echo weed eater and I have had to pull the plugs that hide the carb adjustment needles on both of them to get them to run right once they broke in. It seems they are set very lean from the factory probably due to emissions.

If the 2 stroke engines run considerably better after backing out the needles to enrich the mixture there is a good chance that the mesh screen is becoming clogged and/or the diaphragm is becoming brittle, @Rick. Also, the fuel filter and hose in the tank might be getting emulsified. I was amazed at what came out of the tank on my weed-eater.

Better head this back to a auto centric discussion

This was a lawn mower question, which is now a lawn equipment discussion.

I used to have a black and decker battery powered weed eater, but I switched over to using grass/weed killer spray once or twice a year to clear around the house and other obstacles in the yard.
I didn’t spray before I started mowing, and that’s how I wound up running over a tree stump in my yard with my new rider(delivered that day). It was so short that the grass covered it up. While I thought I was close, but not close enough to run over it, I wound up hitting it and bending the left side blade.
I’ve bought new blades for the mower last week and put both new ones on. I figure this way I’ll know if I just bent a blade or damaged other parts as well. Because the mower is so new, Sears just had the mulching blades available; separately or as part of the mulching package. The blades we $40 or the kit was $55, and the only difference is the kit has a plate that goes where the discharge chute is for the deck; hardly worth $15, IMO

Remember we are not permitted to do anything but auto related discussions(general discussion as long as its auto related){come on give us a real general discussion forum}-Kevin

I know it comes as a disappointment to some that a true General Discussion forum isn’t in the offing from Car Talk. I do encourage you to continue this discussion via the private messages or other means. It started out with a question that was car/engine/fuel related, but it seems that answers have been provided.

geez, this is about fuel and internal combustion engines and fixing carbs and that’s not close enough to car talk?

it was interesting, so of course, close it. have you guys been studying china s internet policy for ideas?