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Discussion Starter #1
Hoping to get a little help diagnosing a problem with a B&S 18.5 hp Intek motor on my riding mower.

If anyone knows their way around small engines and can help I would appreciate it.

When I try to start the motor it turns over fine (new battery less than a month ago) but it won't fire. If I hit it with a little starter fluid it fires up and continues to run without a problem. When I shut it off and try to restart it does the same thing. Doesn't matter if the engine is cold or hot.

Today I replaced the spark plug and fuel filter but still have the same problem.

I'm using 100% gas, no ethanol.

I had just changed the oil and filter but can't imagine that would have anything to do with it.

I'm pretty much out of ideas as to where to look next

Suggestions??? :feedback:
 

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No expert, but had similar problem with12 or 16? hp briggs. With some tryin" I could get it started but if I shut it off it wouldn't start back up!

I talked to a guy with a small engine- lawn mower shop and he said that happens when the compression gets low??? I that it would've been electronic? I never checked it, the mower had other problem so I sold it to a guy for parts...

All I got??
 

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Harley Rider
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Sometimes when the carb isn't flowing correctly, it will flood the cylinder and wont crank up. You might double check and see if there is gas in your cylinder. I have one with that problem now. It requires a rebuild kit on the carb.
 

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Pork Jockey
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Carb. Take it off, clean it, re-install, put fresh gas in it, and start 'er up.

Had to do this recently with a Husky Generator and another power washer. One with a small Honda motor and the other with a Subaru. Easy...
 

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Fla Cajun
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Thats weird, i had to take the carb off my pressure washer today and clean it. It was gunked up around the float. Had to use about a half a can of carb cleaner to git it flowing again. it would crank with a shot of either......If it'll crank with either....it's the carb.
 

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Pork Jockey
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Thats weird, i had to take the carb off my pressure washer today and clean it. It was gunked up around the float. Had to use about a half a can of carb cleaner to git it flowing again. it would crank with a shot of either......If it'll crank with either....it's the carb.
Haha!

A few weeks ago, I did both - Generator and Pressure washer. Heck, they're both essentially brand new. While I've owned 'em for a couple years, they've both seen VERY minimal use.
 

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Most small engine that I've had and had some starting/running problem ended up just needing carb clean and or rebuilt.

Friend gave me a 77 yamaha champ for helping him with his truck yesterday, didn't want anything but he insisted?

Been sitting in his garage for four years and another three before that in his cousins garage.

So last night out in garage and thought I'd tinker with it,

It would act up and chug spit and carry-on with either,pulled carb off and it was like concrete in the float bowl, cleaned it with can and air, ran but not real well, carb dip over night and the thing will go about 45 mph and cop followed kid home on it!!
 

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While I've owned 'em for a couple years, they've both seen VERY minimal use.
There's the key! I have lawnmowers, power equipment, chainsaws, generator. 2 cycle and 4 cycle. User manuals in all cases talk about draining the fuel, running the engine until it clears the carb and stops -- this for when you intend not to use the item for a period of time.

Evidently shellac and deposits gum up the carb. Carb cleaner should fix it. And spring for CARB CLEANER. Don't settle for some sort of "bubba solvent" you found in the woodshed! Carb cleaner comes in handy for cleaning up firearms too!
 

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On the loose
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Ya carbs that sit with gas in them get gunked up with today's fuel. Pull the carb , take the float bowel off, get a can of carb cleaner , put the straw on it and shoot it through every passage you can find followed with compressed air , might as well spray the rest of it while it's off. Check that when it's in the start position that the butterfly is closing , if not it should just be a cable clamp you loosen to adjust it.

Even storing with the legendary Seafoam I've had to pull my float bowel off my snow blower the last 2 yrs and dump some nasty crap outa it .

PS :I agree with xero's post
 

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Discussion Starter #10
i appreciate all of the tips and will follow up on each and every one.

what confuses me is that i used the mower twice within the last month and didn't have a problem either time. cold or hot, when i hit the switch it started right up.

now all of a sudden it just spins unless, as mentioned in my OP, i give it a shot of starter fluid.

i'm using fresh gas and the gas that was in it over the winter was treated with Sta-bil.

thanks for all of the suggestions!!

bob
 

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I used to have same problem every single year with a lawn boy 2 cycle and an 18hp Briggs. Started using Amsoil Sabre in the 2 cycle and started putting Redline injector in the gas for the riding mower about 4 years ago and haven't had a single problem since then. I think both products have some stabilizer in them.


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Try'n to behave
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There's a little tiny opening on the bowl nut that routes gas up to the jet. I've missed cleaning that one on more than one occasion and been given fits over why it won't run.
 

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I worked for almost five years in the rental business as a mechanic and heavy equipment delivery. You would be surprised by the small amount if gunk that would stop a engine from running.

That being said. If you have room in the feed line to the carb, add in an extra filter. Stabil and seafoam work wonders on all things mechanical!
 

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One thing I've found that's works real well is the carb cleaner made by amsoil.
Use to be just adding stabil to the gas was enough but not no more. Ethanol is murder on small engine carbs. And they want to add more.


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STAND AND FIGHT!
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real carb cleaner is very corrosive to anything non-metal,

rubber plastic cork paper gaskets will all be degraded or ruined,

be careful where you use the real thing. If you can get it.

...
 

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Keep on Ridin’
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It's possible that there is an electric shut-off valve on the bottom of the carb bowl that might be clogged or sticking. You might want to look into its operation if you see wires going to the bottom of the carb.
 

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real carb cleaner is very corrosive to anything non-metal,

rubber plastic cork paper gaskets will all be degraded or ruined,

be careful where you use the real thing. If you can get it.

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What he said! If you can (and don't want to buy the carb kit) remove the o-ring on the bowl and if there are any rubber ends on the needles and adjustment screws keep them away from the carb cleaner. If you stretch the o-ring a little, place it in the sun or heat it w/hair dryer and it will shrink.
 
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