109 Not running right and pink exhaust valve?

[J-Mech]

Originally Posted by specthompson

Carb is set to factory settings. I thought you meant if the top of the piston had scores or marks in it. Im telling you guys, it was running VERY good then all of a sudden it tuns terrible. Also I cant get 87 octane fuel without ethanol in it around here in Illinois

The ethanol won't hurt a thing. I live in Illinois too. All the fuel I run is 10% blend. It's fine, no issues.

[Merk]

Originally Posted by Maxwelhse

I might be the only one that sees it this way, but I don't see any evidence of a problem that would have been "sudden". Running fine one day, and running for crap the next, doesn't usually happen with the signs of the lean condition shown unless something flat out broke. About the only thing we can't clearly see is a crack in the piston or broken rings. I wouldn't expect it to idle too happily with either problem but I guess it could happen. I agree that it looks like it could used fattened up, but I don't see that as being your end solution. That's just my opinion, I'm not trying to start a P match.

The brand of the plug isn't your problem either. Condition? Possibly.

Like J said, clean it up, maybe post some more pictures without the carbon, and start at the beginning including proper carb adjustment and a new plug (I do like Autolites but my 149 has a Champion right now... no issues).

It takes time for a lean condition to cause the problems specthompson is having. Something doesn't have break. Champion sparkplugs used to be a good plug. They foul out to easy. I have a new Briggs 2 cylinder Van Guard that will foul out a champion plug 10 to 25 hours. Never the same cylinder. I ran a set of Autolites over 100 hours with no problems before I change them.

[sawdustdad]

I'd be looking for a fuel flow restriction. Plugged screen in the tank?

Do you get good flow from the fuel line when you pull it off the carb?

I don't see anything causing a sudden problem either--but the lean condition could be due to a fuel restriction.,..

[Maxwelhse]

Other than burning the plug up, I'm not sure what a lean will cause without broken parts that will cause a sudden failure (his plug looks lean, but doesn't look burned up to me at the angle the picture was taken). When I say I'm not sure, I mean just that. Coming from the automotive world I'm used to seeing a lean blow up parts or pretty consistently cause performance issues.

My 149 has had its Champion for at least 4 years (100-200hrs.. hard to guess) with no problems. I did buy a super fancy Autolite e-z start for it to put on the shelf for when it needs replacement. I've never tried one before in a larger small engine but my smaller small engines love them. I've had very few problems with Autolite plugs and generally put them in my power equipment. The 149 came into my ownership with the Champion so it stayed.

In regard to taking pictures dirty vs. clean, I was advocating for BOTH.

[specthompson]

I didnt clean anything when I took those pics

[specthompson]

Also it has very good flow of gas coming from the fuel line

[J-Mech]

Originally Posted by specthompson

Also it has very good flow of gas coming from the fuel line

Then you probably had the carb set too lean, or the main is plugged. Or you have a vacuum leak either in the throttle shaft or the carb base gasket.

Maxwelhse, Merk didn't say it was burned up..... he said he can tell it's a lean condition by the look of the electrode. Which I see also. You can also see the hot-spot on the head, and around the piston. Pre-ignition.

Oh, and to answer the original question, the exhaust valve looks like that because of the heat.

[specthompson]

So pretty much i gotta put a new plug in, ritchen up and clean my carb then my problem should be fixed? By the way ive ran that engine since march with the factory carb settings and 90 octane fuel. Also i dont like the idea of running fuel with ethanol in it and 90 octane is my only choice so should i keep running that?

[olds45512]

i prefer 89 octane but i doubt 1 more octane will hurt.

[Maxwelhse]

Originally Posted by J-Mech

Maxwelhse, Merk didn't say it was burned up..... he said he can tell it's a lean condition by the look of the electrode. Which I see also. You can also see the hot-spot on the head, and around the piston. Pre-ignition.

I gotcha and I see it too. I was pointing it out as about the only thing I'm aware of that will make an engine run bad, suddenly, based on a lean without breaking parts. I'm participating as much for my own education as anything so I was hoping for some more info about sudden failures from a lean without engine damage.

Originally Posted by specthompson

So pretty much i gotta put a new plug in, ritchen up and clean my carb then my problem should be fixed? By the way ive ran that engine since march with the factory carb settings and 90 octane fuel. Also i dont like the idea of running fuel with ethanol in it and 90 octane is my only choice so should i keep running that?

90 isn't HURTING anything but your wallet and the tractor doesn't need it. I not one to fret over ethanol either, but to each their own. My Cub has seen nothing but 87 its entire life (well... since the mid-late '80s), winter/summer/ethanol or not.

As I've read the thread, check your carburetor and the entire fuel system over for trouble, replace the plug, and check your timing. Seems like a solid plan to get started with the rest of the diagnosis.