7.25 Craftsman self propelled lawnmower won't start after new carb install?

[boycottg00gle]

Hi all, my 2011, 7.25 craftsman lawnmower still doesn't want to start after installing a "new" carburetor, filter, air filter, new plug, and it's actually worse now that I put on a new carb. It was hard starting before the new carb (first start), but it at least started after oh, 10 pulls. Now it won't start at all? It has fuel, as the plug is wet, I tried the old plug too, I ordered two more new plugs just in case, it's a weird plug issue? I have spark, as it did try to start for a few seconds, but won't stay running, now it won't even do that? I set the gap to the recommended .030, and tried a few other gaps up to .035, and still no luck!

Maybe? it's just flooded from trying to start? I don't know much about it? I even pulled the bolt out of the carb bowl to make sure it's 3 holes were clear. Well, I had enough fun for today! PS, the auto choke spring is attached, as apparently they can fall off or break! Maybe? it's a carb adjustment thing that I can't seem to change? or a dud carburetor? I didn't have any problems with the bar, or kill switch linkage set up before, so don't I think it's that? Not sure where to go from here! Any incite would be greatly appreciated! Thanks!

 

[bertsmobile1]

As the plug is wet that tells us that fuel has come into the cylinder & failed to ignite
So that points to the spark failing or being out of time .
To check the timing remove the flwheel bolt and check that the 2 halves of the key ways come together to make a perfect square , if there is the slightest step between then the key has sheared and the engine is out of time .
And of course check you are geting a spark.
The old wet plug by now is useless unless you burn the fuel off as unburned fuel will leave a slight oily film on the electrode so the spark will track down the side rather than jump the gap & ignite the charge under cylinder pressure .
Sparking when outside the engine does not mean it will spark inside the engine.
The old Champion spark plug testers used to increase the pressure till the spark can no longer jump the gap.
This is a test done to every spark plug on the production line before they are labled and packaged .

 

[StarTech]

And new doesn't always means good. This is why you use a known good for testing.

 

[boycottg00gle]

As the plug is wet that tells us that fuel has come into the cylinder & failed to ignite
So that points to the spark failing or being out of time .
To check the timing remove the flwheel bolt and check that the 2 halves of the key ways come together to make a perfect square , if there is the slightest step between then the key has sheared and the engine is out of time .
And of course check you are geting a spark.
The old wet plug by now is useless unless you burn the fuel off as unburned fuel will leave a slight oily film on the electrode so the spark will track down the side rather than jump the gap & ignite the charge under cylinder pressure .
Sparking when outside the engine does not mean it will spark inside the engine.
The old Champion spark plug testers used to increase the pressure till the spark can no longer jump the gap.
This is a test done to every spark plug on the production line before they are labled and packaged .

Hi, thanks so much for taking the time to reply! I will do that, as I was going to venture into the auto choke system as well just in case it was flooding? so I will check the timing too while I'm in there!

So, if the timing is out? and it ran before my changing the carb, considering it was still hard starting, had to pull a few times to start, 1st season start was the hardest, but after that, it wasn't too bad, maybe 5-7 pulls! So, the question would be? if the timing was / is out would it have even ran, and worked so well before I changed the carb, my problem was hard starting is why I changed the carb, and instead of rebuilding it, it was cheaper to get a new one, that came with all the other things I needed? Could this timing thing have happened just now? PS, I did order two new plugs, just in case, the one I got is a dud from new. Once again thanks for replying!

 

[boycottg00gle]

And new doesn't always means good. This is why you use a known good for testing.

If you meant the new spark plug may not be good? I did order two new plugs yesterday, just in case the one I got is a dud? It's hard to check the strength of spark by myself, but will figure that out! Thanks for your input!

 

[Rivets]

If you got your new carb off Fleabay or Amazony, there is a good chance it is bad or the wrong carb. Using these two sites is a crap shoot as they often sell defective and miss labeled parts.

 

[boycottg00gle]

Oh that is super great to hear, yes I did get it off amazon!!! I just checked the valve timing and it is correct, but I watched a video where the cam shaft timing was out, even though the valve timing looked okay! Holy frickin can of worms, I'd rather be baking cookies right about now! Thanks for the info, I guess I'll take the old carb, and clean it up for now. I'll be pissed if that's what it actually is! Okay, thanks for your reply!

 

[boycottg00gle]

Oh that is super great to hear, yes I did get it off amazon!!! I just checked the valve timing and it is correct, but I watched a video where the cam shaft timing was out, even though the valve timing looked okay! Holy frickin can of worms, I'd rather be baking cookies right about now! Thanks for the info, I guess I'll take the old carb, and clean it up for now. I'll be pissed if that's what it actually is! Okay, thanks for your reply!

I just ordered a needle and seat for my old carb, sick of screwing around! Looks like the carb I bought is different (like you said) then the brigg's part # I ordered, now fuel is pouring out the carb intake! So I ordered a needle and seat for that issue! Well at least I'm learning something! I'll be a professional by the time this ends! Thanks again!

 

[bertsmobile1]

WE look forward to you becoming an expert and answering the questions of others .
usually when assessing an unknown engine that does not start I resort to an orange in line spark tester ( so I can see it in the daylight ) and a can of carb cleaner ( used as starting fluid )
With the tester installed a SHORT shot down the spark plug hole and crank the engne.
If it fires a few times then I can be sure the plug is working and the ignition timing is reasonable .
Then it is a quick shot down the carb mouth and crank again
Engine fires a few times burning off the fuel then I know that the valves are working.
If I can keep the engine running for a minute or so by shooting a small amount of carb cleaner down the carb throat then I know the valve timing is OK and the problem is in the carburettor .
The whole time I watch the spark tester to check the orange flashes are consistant and stable .

Now if it starts quickly and runs all by itself then the problem is with the priming / choke system .

For nice pictorial instructions on cleaning the carb go to Outdoor Power Equipment carb page

 

[boycottg00gle]

WE look forward to you becoming an expert and answering the questions of others .
usually when assessing an unknown engine that does not start I resort to an orange in line spark tester ( so I can see it in the daylight ) and a can of carb cleaner ( used as starting fluid )
With the tester installed a SHORT shot down the spark plug hole and crank the engne.
If it fires a few times then I can be sure the plug is working and the ignition timing is reasonable .
Then it is a quick shot down the carb mouth and crank again
Engine fires a few times burning off the fuel then I know that the valves are working.
If I can keep the engine running for a minute or so by shooting a small amount of carb cleaner down the carb throat then I know the valve timing is OK and the problem is in the carburettor .
The whole time I watch the spark tester to check the orange flashes are consistant and stable .

Now if it starts quickly and runs all by itself then the problem is with the priming / choke system .

For nice pictorial instructions on cleaning the carb go to Outdoor Power Equipment carb page

Thank you for that! I will watch that video now! I was trying to figure out how to test for a "full" spark all by myself! I don't have someone to help or watch, I'm a micky bojang kinda female making due! Using what I have for tools! PS, I use to be an auto mech, eons ago, but never did much with small engines! It's been at least 30 years! And you do forget!