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3.5HP Briggs & Stratton Moter Dose Not Work (Boggs Down)


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01-22-08, 02:15 PM   #1  
3.5HP Briggs & Stratton Moter Dose Not Work (Boggs Down)

Every time I try to start up my old Craftsman mower with a 3.5hp Briggs & Stratton motor on it, it boggs down immediately. i have cleaned out the carb., put a new air filter on it, add new oil, put new gas in it and tryed to wash all of the dirt off of it. the throttle govnor is not stuck and moving and the piston has been cleaned off. no matter what i do, the thing wont start up!!!

The engine model number is: 143.374032


Can someone please help me?
Thanks,
Chris

 
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01-22-08, 03:31 PM   #2  
The model number you posted is for a Tecumseh so here we go;
Clamp off the fuel line, remove the carb bowl, release the clamp to see if you have good fuel flow to the carb, raise the float to see that it shuts off the flow with minimal pressure, clean the junk from the bowl, clean the bowl nut, 2 holes close to the bottom and a tiny one about midway up(I usually use the wire from a twist tie), spray all holes, cracks and crevases with brake parts cleaner, reassemble and you should be good to go. If this didn't work it will be probably be necessary to rebuild the carb. If I missed something one of the real mechanics will post to help further. Refer to the photo below. Have a good one . Geo
http://i190.photobucket.com/albums/z...c_bowl_nut.jpg

 
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01-22-08, 03:43 PM   #3  
geo is right, you have a Tecumseh engine, TVS90-43354E.
How did you clean carb, spray can carb cleaner or soak in carb bath a couple of hours??
After you cleaned piston, did you clean gasket and reinstall head/gasket bolts in criss-cross fashion to 150 in. lbs.?
Could it use a new spark plug ?
thanks,

 
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01-23-08, 12:37 PM   #4  
I have replaced the pistion rings and cleaned off the valves. The carb. is getting a good flow of gas and should be working ok. I have also tryed 3 new sparkplugs.

Do you think it would be better to get a newer and working motor of Ebay?

 
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01-23-08, 12:57 PM   #5  
I wouldn't give up on this one yet, they are fairly simple engines.
Did you:
1) follow geo's advice on main jet cleaning? pull up his picture? This is oftentimes the problem with a Tecumseh....
2) Torque the head bolts properly ??
3) After installing new rings, did you make sure the cam gear was properly timed to crank prior to re-assembly?
The 692509 service manual at the following location covers your model.
http://toprake.com/index.php?module=...position=11:11
Good luck,
thanks,

 
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01-23-08, 02:28 PM   #6  
ill try everthing he said. the only problem is that i cant pull up his picture. it says: The page you are looking for cannot be found.

 
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01-23-08, 02:50 PM   #7  
Let me more descriptive on the problem here:
After a few pulls, my lawnmower trys to start up. even without priming it, the engine revvs up like it should. after 2 seconds of running, the engine backfires or stalls.

Because i am familiar with both 2 and 4 stroke engines, i think that the problem is not the carborator. it could be the ignition timing or the cylinder has sized or a loss of compression. Even a worn valve could of caused this.
I think it would take too much time and or money to try to replace every single part in it.

I Don't Know What To Do!

 
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01-23-08, 03:22 PM   #8  
spanky;
Here is a new link I just got see if it will show you the bowl nut(main jet). Have a good one. Geo
http://i190.photobucket.com/albums/z...c_bowl_nut.jpg

 
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01-23-08, 03:52 PM   #9  
Well, you can do what we've suggested thus far, especially making sure the bowl nut(jet) is pristine.
Let us know,
thanks,

 
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01-23-08, 06:31 PM   #10  
Yes i have seen this nut before. it holds the float bowl on and limits the amount of gas to the jet needle. I had done what you have toled me to do and stuck a small copper wire into it. but the engine still has this problem.

 
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01-23-08, 07:16 PM   #11  
just to let you know, my name is Chris. My birds name is Spanky.

 
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01-23-08, 07:26 PM   #12  
Chris, I know it's unrelated, but what kind of bird is Spanky. Have a good one. Geo

 
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01-23-08, 08:36 PM   #13  
Chris,
Your ideas in post #7 are good things to check,compression, valve issue, like tappet clearances, a failing coil is maybe a possibility.
The manual I suggested in post #5 will give procedures, specs, etc. on these items.

Give my regards to Spanky,
Good Luck,
thanks,

 
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01-24-08, 03:05 PM   #14  
Glen, Thanks for tha advice. I have the motor apart and I am still working on it.

Geo, my bird is a Cockatiel.


Thanks for the info.

I'm still working on the motor.

 
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01-24-08, 03:17 PM   #15  
Since you have the motor apart, I will assume the flywheel key is good. Gas cap venting ok?

 
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01-24-08, 03:25 PM   #16  
Hi, I've run the motor without the gas cap and the air filter before. same problem.


I have just finished measuring the valve sizes and replaced the piston ring. The camshaft and the piston rod are not damaged and the ignition timing is set correctly. The voltage is at the correct amount (22,000 volts).


nothing has changed the performance.

 
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01-24-08, 06:13 PM   #17  
Posted By: spanky068 Every time I try to start up my old Craftsman mower with a 3.5hp Briggs & Stratton motor on it, it boggs down immediately. i have cleaned out the carb., put a new air filter on it, add new oil, put new gas in it and tryed to wash all of the dirt off of it. the throttle govnor is not stuck and moving and the piston has been cleaned off. no matter what i do, the thing wont start up!!!

The engine model number is: 143.374032


Can someone please help me?
Thanks,
Chris
Have u checked the spark plug gap?

 
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01-24-08, 06:24 PM   #18  
i've tryed 3 new sparkplugs and mesured there gap.

 
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01-24-08, 06:29 PM   #19  
i know that it is the carb that is not working. the thing is about 23 years old.
I still don't want to give up yet because after 63 pulls, the mower finally runs perfectly.

 
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01-24-08, 06:54 PM   #20  
I just want to ask,
Is there any adjustments on the carborator? one of my friends said that the old carbs had the adjustments hidden and the only way of getting to them was to drill them out. is this true?

 
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01-24-08, 10:17 PM   #21  
No, there are no adjustments to drill out. If it doesn't have adjustments visible, then there aren't any. Soak the carb in a good bath type carb cleaner and you should solve the rpoblem.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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01-25-08, 04:05 AM   #22  
Posted By: spanky068 i know that it is the carb that is not working. the thing is about 23 years old.
I still don't want to give up yet because after 63 pulls, the mower finally runs perfectly.
.....mower finally runs perfectly ?? Great !
63 pulls is excessive, how many times you push primer bulb ??
Have you tried putting a teaspoon of gas in sparkkplug hole, or carb throat, or, shot starting fluid in carb throat ??
Enter 632387 (carb #) in model # box at:
http://www3.sears.com/
There's hardly any other carb simpler than this one, no adjusting needles, no choke,etc.
Ref #9 shows the simple primer bulb and it's retainer gizmo,(must be careful when using this highly technical term)
Might be all that's needed now is a new, firmly seated, primer bulb.
Let us know,
thanks,

 
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01-26-08, 07:58 AM   #23  
I've just put an order in for a new primer and a new throttle governor spring. I'll let you know when I receive these items.



-Chris-

 
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01-28-08, 05:13 PM   #24  
By the way, dose anyone know were I can find one of those carburetor baths? I think that would help.




Thanks,
Chris

 
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01-28-08, 05:45 PM   #25  
They come in 1 gal cans, Wal-Mart, or any auto parts place, common brands are Gunk, Berryman's, NAPA has a popular one.
thanks,

 
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01-30-08, 04:19 PM   #26  
I've just have a question,
How do you remove the primer on the carb.?

 
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01-30-08, 07:04 PM   #27  
If you look at the diagram I referenced in post #22, you will see the round spring clip gizmo that holds the primer bulb in it's well, pry it out with a thin bladed screwdriver,
the new primer bulb will come with a new spring clip retainer,
thanks,

 
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02-04-08, 09:08 AM   #28  
I have finally fixed the mower. It starts up instantly and runs smoothly.


Thanks soo much for your help!

-Chris-

 
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02-04-08, 10:04 AM   #29  
Great ! Good job !

 
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