Engine Turns Strong but Will Not Start

Seafire

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Hello and Thank You, New to the Forum with a Craftsman T-2500 (917.255. . .) 46 inch deck 3 years old. A month ago I am happily riding and mowing on level ground just making a summer pass over the weeds when for no apparent reason the engine just stops, no clink, clank, cough, just stops. Gas tank half full. So, off I got, scratching my head quite perplexed. So, old school thinking . . . fuel flow or no spark . . . pulled the spark plug, ground it turned the engine saw decent spark, so must be fuel flow, wondered just where the electric fuel pump must be. Quite surprised to discover it had a vacuum driven fuel pump, my first experience with such a thing, but finally figured that out, so pulled the fuel line at the carburetor and had a gusher of fuel flow. So, good spark, good fuel, why no go??? The odd thing, I can get the engine to crank by standing next to the mower stepping down on the "parking brake" and turning the key and not sitting in the seat. I have downloaded the manual and some of the schematic details and I am hazarding a guess that somehow the safety switches have failed or crossed over or ???? So I am turning to the experts who in all their multilayered experience and wisdom have most likely encountered this same baffling problem and found that it was just the thingamgig that had gotten disconnected form the watchamaallit and all I need to do is reboot the main drive and download the quick fix patch for Windows 3.1. Now I am off to a meeting for the next few hours, but all along while the others are musing over the topic I will inwardly anticipating the simple fix and perhaps even later this afternoon happily encouraging the weeds to stand tall and receive a trim.
 

shiftsuper175607

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Hello and Thank You, New to the Forum with a Craftsman T-2500 (917.255. . .) 46 inch deck 3 years old. A month ago I am happily riding and mowing on level ground just making a summer pass over the weeds when for no apparent reason the engine just stops, no clink, clank, cough, just stops. Gas tank half full. So, off I got, scratching my head quite perplexed. So, old school thinking . . . fuel flow or no spark . . . pulled the spark plug, ground it turned the engine saw decent spark, so must be fuel flow, wondered just where the electric fuel pump must be. Quite surprised to discover it had a vacuum driven fuel pump, my first experience with such a thing, but finally figured that out, so pulled the fuel line at the carburetor and had a gusher of fuel flow. So, good spark, good fuel, why no go??? The odd thing, I can get the engine to crank by standing next to the mower stepping down on the "parking brake" and turning the key and not sitting in the seat. I have downloaded the manual and some of the schematic details and I am hazarding a guess that somehow the safety switches have failed or crossed over or ???? So I am turning to the experts who in all their multilayered experience and wisdom have most likely encountered this same baffling problem and found that it was just the thingamgig that had gotten disconnected form the watchamaallit and all I need to do is reboot the main drive and download the quick fix patch for Windows 3.1. Now I am off to a meeting for the next few hours, but all along while the others are musing over the topic I will inwardly anticipating the simple fix and perhaps even later this afternoon happily encouraging the weeds to stand tall and receive a trim.

I'm leaning toward fuel problem.

It still has to get through the carburetor into the engine.

Will it start with a spray of starting fluid or teaspoon of gas after removing air cleaner?
 

PTmowerMech

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Hello and Thank You, New to the Forum with a Craftsman T-2500 (917.255. . .) 46 inch deck 3 years old. A month ago I am happily riding and mowing on level ground just making a summer pass over the weeds when for no apparent reason the engine just stops, no clink, clank, cough, just stops. Gas tank half full. So, off I got, scratching my head quite perplexed. So, old school thinking . . . fuel flow or no spark . . . pulled the spark plug, ground it turned the engine saw decent spark, so must be fuel flow, wondered just where the electric fuel pump must be. Quite surprised to discover it had a vacuum driven fuel pump, my first experience with such a thing, but finally figured that out, so pulled the fuel line at the carburetor and had a gusher of fuel flow. So, good spark, good fuel, why no go??? The odd thing, I can get the engine to crank by standing next to the mower stepping down on the "parking brake" and turning the key and not sitting in the seat. I have downloaded the manual and some of the schematic details and I am hazarding a guess that somehow the safety switches have failed or crossed over or ???? So I am turning to the experts who in all their multilayered experience and wisdom have most likely encountered this same baffling problem and found that it was just the thingamgig that had gotten disconnected form the watchamaallit and all I need to do is reboot the main drive and download the quick fix patch for Windows 3.1. Now I am off to a meeting for the next few hours, but all along while the others are musing over the topic I will inwardly anticipating the simple fix and perhaps even later this afternoon happily encouraging the weeds to stand tall and receive a trim.

But it won't start while you're sitting in the seat?
 

Seafire

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I'm leaning toward fuel problem.

It still has to get through the carburetor into the engine.

Will it start with a spray of starting fluid or teaspoon of gas after removing air cleaner?

Took me a while to get back to the mower, but thank you very much for your thought . . . you are right. I dribbled some gas into the air intake and the engine fired up. So Now I am looking at the wires that come out of a small sliver can on the bottom of the carb. Black wire is ground, and then a white wire running under the engine and into a bundle on the other side. Unsnapped the plug and the ground part of the plug appears blackened, the other end is a good solid ground to the engine. I have no idea what this little cannister is, solenod? a pot? what? but it is my guess that this device needs to be swapped out. I will track it down tomorrow and look forward to your thoughts. The other thing that bugs me is that the engine will turn over without me sitting in the seat, but I do have to push down the "brake" does this device have some kind of feed back into the rest of the ignition circuit? . . . Again, thanks for the heads up.
 

Seafire

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But it won't start while you're sitting in the seat?

No, turns out there is some kind of fuel flow problem. Some part of the carb is not allowing fuel flow through the carb -- fiddled some gas into the air intake and she fires, so now I am looking at the little silver can under the carb that has two wires going into it. Do not know what it is but will work on that tomorrow. Thanks for your help.
 

bertsmobile1

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It s called an anti after fire solenoid.
IT rams a bung up the main jet preventing fuel from entering the engine via the main jet after you have turned the engine off thus you are not venting unburned fuel into the atmosphere threatening the very existence of life on the plant.
You are now going to vent 1000 times the amount of unburned fuel the solenoid prevented escaping into the atmosphere by diagnosysing & repairing the carb.

The easiest test is to replace it with a bolt 5/8 UNF x 1/2" from memory.
Mower runs fine then the solenoid or wiring to it are faulty.
Sitting at the absolute bottom of the float bowl all the detritus ends up in it causing it to jamb
 

Seafire

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It s called an anti after fire solenoid.
IT rams a bung up the main jet preventing fuel from entering the engine via the main jet after you have turned the engine off thus you are not venting unburned fuel into the atmosphere threatening the very existence of life on the plant.
You are now going to vent 1000 times the amount of unburned fuel the solenoid prevented escaping into the atmosphere by diagnosysing & repairing the carb.

The easiest test is to replace it with a bolt 5/8 UNF x 1/2" from memory.
Mower runs fine then the solenoid or wiring to it are faulty.
Sitting at the absolute bottom of the float bowl all the detritus ends up in it causing it to jamb


DETRITUS?! DETRITUS!!! . . . isn't that what you throw on the barby to clean it after the shrimp are done. . ?? (have not heard that word since my Forestry class when talking about the "stuff" under the trees ie, Forest Floor Detritus -- probably not to different from what is in the bottom of a float bowl).

And thank you very much for the info, having never seen an anti after fire solenoid before so not having a clue as to what or why it does or doesn't do. Obviously this is the problem, the question remains as to why it suddenly failed, is that typical? not a broader problem with the ignition/wiring? My approach today, remove the beasty and replace with appropriate bolt to verify failure, reinstall and hot wire the grey wire to the battery to bypass the ignition/wiring just to make sure it truly is the malfunction. Then I guess it is search out a replacement.

Thank you very much for your educated and educational reply. Kudos, back slapping, and cheers all around.
 

Seafire

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Thanks to all I plan to mow today. Yesterday I tracked down a 1/2" 5/16-28 bolt (closest I could find at Pierson's Hardware) added a couple of washers so that it would only grab 1-1/2 turns and screwed it into the bottom of the carb to take the place of the anti fuel flow solenoid and she started right up after pumping gas and appears to run fine. So I am going to grind off the plunger part of the solenoid so that it does not engage and go mow. Replacement solenoids at Sears and at local small engine shops were quoted at $50-75 . . . and on the net at $6-10 so plan to replace it soon but would like some advice on who on the net to buy from (if that question is appropriate here). Or I was thinking an in line fuel cut off and when done for the day cut off the fuel, run the remaining gas out and be done. At any rate I appreciate the good directions from all, I had never heard of an anti fuel flow solenoid before.
 

JerryMc77

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The "can" at the bottom of the carburetor is an anti-backfire solenoid. All it does is stop your fuel flow when you shut your engine off. I have a Kohler courage 20hp engine on my mower and I took a Dremel and cut the plunger off the solenoid and installed a manual shut off valve (about $4.00) . Just remember to turn the shut-off valve on when you get ready to mow and off when you are done. If you don't shut it off when you're done you stand a chance of your fuel siphoning into the crankcase---not good!!
 

bertsmobile1

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Check if it is working by hooking it up directly to the battery several times.
They rarely fail electrically
However the wire that powers them does get broken, chewed through by mice, melt & short out on the cylinder.
 
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