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Craftsman Lawnmower (only 1 year old) Not Completely Smooth - Video Enclosed

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  • May 4th, 2017 11:42 pm
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Jan 25, 2007
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Paris
ChubChub wrote:
Apr 19th, 2017 1:18 pm
Clean the carb, and run proper fuel; ethanol be damned, higher octane fuel will result in less power, and those carbs are pretty questionable even with proper fuel. As well, it sounds like the timing is wrong on the engine (which should basically be impossible); did you happen to stall it on a root or something?

Might want to replace the plug as well; should be fine, but running like that, it won't be nice for long.
Higher octane less power?

An engineering classmate of my brothers who works in traditional gasoline told us to only use mid or high grade gas in small engines as the preservatives in regular gas were only good for 30 days until the gas started to break down vs mid and high are 6 months. So buy a gallon of fuel at the beginning of the season and the gas has started to go bad by August.
Gbill2004: Thanks but I'll just smell the couch before/if I buy it.

jonnyb: I go in there like PICASSO and toss the glue everywhere, I don't care what house I'm on.
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Oct 9, 2010
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Windsor
Jerico wrote:
Apr 19th, 2017 1:22 pm
Higher octane less power?

An engineering classmate of my brothers who works in traditional gasoline told us to only use mid or high grade gas in small engines as the preservatives in regular gas were only good for 30 days until the gas started to break down vs mid and high are 6 months. So buy a gallon of fuel at the beginning of the season and the gas has started to go bad by August.
Less power, but more resistance to detonation ... so, you can run higher compression without detonating, so you get more power. However, if you're not modifying the combustion chamber, or somehow getting more air in there (turbo/supercharger ... porting), you'll end up with less power.

As for how long gas takes to go bad, I'm not sure; those numbers seem to be VERY conservative. My 600RR had 91 octane fuel in it (minimum recommended octane) for 5 years while I was across the country (not started once); when I came home, it started fine, and I wasn't getting any knocking.
One who is offended by truth, has no place among those who seek wisdom.
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Feb 9, 2006
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Brampton
Jerico wrote:
Apr 19th, 2017 12:19 pm
How do you test for ethanol?
A cheap way to do it but you ruin the gas is to take a small amount and pour water in it.

Note how the gas and the water obviously settles in to their specific gravities.

Shake it, give it time if the water section increases in height there's Ethanol. Water pulls the Ethanol out of the gas.
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Jan 25, 2007
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Paris
ChubChub wrote:
Apr 19th, 2017 1:29 pm

As for how long gas takes to go bad, I'm not sure; those numbers seem to be VERY conservative. My 600RR had 91 octane fuel in it (minimum recommended octane) for 5 years while I was across the country (not started once); when I came home, it started fine, and I wasn't getting any knocking.
I agree they are conservative. I think that is when the gas starts to break down.

I would say the fuel issues only started 3-4 years ago like the attached video with a rotten fuel line from a sled.


Plus storing my ZX6 next to a ZZR250 I ALWAYS had Spring gas issues with the 250 whereas the 600 fired right up. Fouled the plugs on the 250 even. That bike was otherwise bullet proof.
Gbill2004: Thanks but I'll just smell the couch before/if I buy it.

jonnyb: I go in there like PICASSO and toss the glue everywhere, I don't care what house I'm on.
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Apr 3, 2008
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Jerico wrote:
Apr 19th, 2017 12:19 pm
How do you test for ethanol?
You can buy test kits but you don't have to.



This is just an example.

Obviously most people don't have a graduated cylinder but you can just use a water bottle, etc and mark the amounts on the bottle with a marker.

Here is a terrible quality video but it shows it with a water bottle.

[OP]
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Apr 1, 2001
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I emptied the gas tank (drained all the gas out via the fuel line) and took apart the carburetor today. It's one of the new plastic Briggs & Stratton carburetors. No visible gunk or residue on it (in fact, all of the parts looked very clean), but I sprayed everything down with some carb cleaner anyway.

Will get some Shell 91 octane gas tomorrow, add Sta-Bil stabilizer right away, and see if it runs smoother... If it doesn't, I'm thinking I'll have to bring it in for the experts to figure out what the issue is.
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Jul 19, 2014
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Snow Road Station, O…
Arrow wrote:
May 4th, 2017 1:06 am
I emptied the gas tank (drained all the gas out via the fuel line) and took apart the carburetor today. It's one of the new plastic Briggs & Stratton carburetors. No visible gunk or residue on it (in fact, all of the parts looked very clean), but I sprayed everything down with some carb cleaner anyway.

Will get some Shell 91 octane gas tomorrow, add Sta-Bil stabilizer right away, and see if it runs smoother... If it doesn't, I'm thinking I'll have to bring it in for the experts to figure out what the issue is.
Splurge $5 and buy a spark plug and replace it you"ll have a better chance of success. Or at least try cleaning up the old plug .
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I put Sta-Bil into the fresh gas I bought today. Should I also put a bit of Seafoam in the same tank?

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