Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

B&S #252707 Problem


tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-01-06, 10:21 AM   #1  
B&S #252707 Problem

I have Briggs & Stratton Model: #252707 / Type: 0621 / Trim: 91031511 on my mower and today, after years of reliable service, it blew white smoke out the exhaust pipe and refused to start. After removing the air filter, it reluctantly fired up and ran rough at idle speed. It appeard to be wet and black inside the carb barrel though. It will not run with the (clean) air filter attached and squeezing the (new) fuel supply pipe seemed to help keep the engine running. Any ideas please?

 
Sponsored Links
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-02-06, 01:36 AM   #2  
The running symptoms and squeezing the fuel line thing make me tend to think the carb is flooding. The white smoke doesn't go well with that theory though. Could it have been black smoke? Is there a gassy smell to the oil?


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

God bless!

 
puey61's Avatar
Member

Join Date: Apr 2004
Posts: 3,224
NY

05-02-06, 02:59 AM   #3  
The black inside the carburetor may be oil and then you could have a defective crankcase breather. The breather vents into the air cleaner and if defective, you will find a puddle of oil there and subsequent oil smoking. Bear in mind, though, that if you have an air-leak elsewhere in the crankcase (PTO seal, Mag seal, sump gasket, oil fill or drain, governor shaft or the breather gasket itself) oil will want to take the easiest route out. And the breather tube is the path of least resistance. So, it may not necessarily be the breather assembly at falult. The best way to find the source of any crankcase air leak is to do a crankcase vacuum test.

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-04-06, 03:54 AM   #4  
reply

Thank you for your reply cheese. It was definately white smoke though as I recall being alarmed at the time at it's colour. It will now run at idle speed but is is very rough and lumpy and the white smoke has gone. I was hoping perhaps the white smoke could have been due to wated intake into the muffler from the weather cover I put on the mower for outdoor storage. However, it will not take any revs and stops... There was a bad gassy smell ok as there appeared to be a lot of it leaking back through the barrel of the carb and when the engine cut out, the residue in the carb was coloured black.

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-04-06, 04:00 AM   #5  
reply

Thanks puey61. This is very good information.

 
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-05-06, 12:00 AM   #6  
How about the oil? It definitely sounds like the carb is flooding and in need of cleaning/reconditioning.


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

God bless!

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-06-06, 03:16 AM   #7  
gas in the engine oil

Hi Cheese. I had the time this morning to go back to my old mower. I checked the quality of the engine oil and there is a very definite smell of gas from it but as soon as I turned the key, the engine fired up immediately . No more white smoke thankfully!! I let it idle for approx. 5 minutes and then opened the throttle gradually and the engine revs built up and up to normal but with a small splutter every now and then. I then shut the engine down normally and tried a hot start... no problem there either. So I shut it off (no backfire/afterfire). What should I do about the engine oil cheese? What would you recommend next to prevent the gas contaminating it?

 
mla2ofus's Avatar
Member

Join Date: Jan 2005
Posts: 478
TX

05-06-06, 04:47 AM   #8  
Tom, I had the same problem w/ my 252707. got a Briggs float needle kit that came w/ one viton tipped needle and one steel needle w/ a plastic? needle seat. Tried the viton and it still leaked, so installed the plastic seat and steel needle and it stopped the leak. I guess the original seat was worn out. The kit # is 394681.
Hope this helps,
Mike

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-08-06, 02:18 AM   #9  
Thanks Mike

Hi Mike. Thank you for your reply. It's nice to know I'm not the only one with a 252707! I have ordered the kit from the local dealer here in Ireland (along with other parts) and will keep you posted on my progress. Thanks again.

 
mla2ofus's Avatar
Member

Join Date: Jan 2005
Posts: 478
TX

05-08-06, 04:19 AM   #10  
Glad to help, Tom. Pay close attention to the seat as it has a radius on the hole thru it on one side only. Be sure this side faces the needle. If you install without removing carb, use a peice of dowel small enough to fit in bore seat goes in. put a small dab of grease on end of dowel to hold seat on it. Trust me, the voice of experience speaks. If you drop it, it's hard to spot even on a concrete floor.
Mike

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-09-06, 11:01 AM   #11  
Gosh Mike, it's very kind of you to offer these words of wisdom and keep me on track. Thanks very much.

 
puey61's Avatar
Member

Join Date: Apr 2004
Posts: 3,224
NY

05-09-06, 02:59 PM   #12  
Tom, if you remotely believe that there is fuel in the oil, do not run it again! Gasoline is not a good lubricant and you can wind up with serious internal engine trouble. Rebuild the carburetor first and then be sure to change the oil (with SAE 30W) again before running. I'm not sure if you have SAE-certified (Society of Automotive Engineers) oil over in Ireland so just be sure to use a quality name brand automotive-type oil.

 
tomkildare's Avatar
Member

Join Date: May 2006
Posts: 7

05-15-06, 09:24 AM   #13  
Yes.... definately gas in the engine oil and quite a lot of it.... In the process of rebuilding the carb at the moment and I have lots of Castrol SAE 30W on stand by. Thank you for the advise.

 
chasepi's Avatar
Member

Join Date: May 2006
Posts: 2

05-18-06, 04:22 PM   #14  
Carb tank gasket

I have this same engine on a tractor my sister gave me Briggs & Stratton Model: #252707. The problem is the little tank on the carb that holds the gas, it leaks. It needs a new gasket, any ideal of a part number or where i could get one that would work.

Thanks for any help
Ken

 
puey61's Avatar
Member

Join Date: Apr 2004
Posts: 3,224
NY

05-19-06, 03:01 AM   #15  
chase, if it is the carburetor bowl gasket you're referring to then you have more trouble than the bowl gasket. The fuel level doesn't even reach this point in the carb. This indicates that the inlet needle & seat or the float are in need of replacing. For any parts, you will need to supply the type and code numbers of the engine as well, not just the model. I'd suggest a complete carburetor reconditioning using a Briggs rebuild kit.

 
chasepi's Avatar
Member

Join Date: May 2006
Posts: 2

05-19-06, 03:15 PM   #16  
Thanks for the help Puey, you are correct after fixing the gasket it found a new place to leak out. I also bought a rebuild kit, so i'll give it a try wish me luck, it dosen't come with directions...lol

Thanks again

Ken

 
puey61's Avatar
Member

Join Date: Apr 2004
Posts: 3,224
NY

05-20-06, 08:21 AM   #17  
chase, you also most likely have fuel in the oil. Be sure to change it before running it again.

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-21-07, 05:27 PM   #18  
I got a rebuild kit for the carb on my 252707. It has a small green "seal". Is this the seal that goes under the needle valve? I have the parts manual and it doesn't show a seal under the needle valve.

Thanks

 
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-21-07, 08:08 PM   #19  
Does the original carb needle have a rubber tip, or is it all metal? If it is metal, then there is a seat that needs to be changed. If it is rubber-tipped, then you have no seat to change. Sometimes a carb kit includes parts that are not needed in all carbs. They put enough parts in the kits so that the kit will rebuild one of several similar, but slightly different carbs.


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

God bless!

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-21-07, 08:25 PM   #20  
The original was all metal. I didn't notice a seat in the carb. The original also had a spring which according to the instructions was not to be used since the engine had a fuel pump. Perhaps someone rebuilt it before and didn't know not to put the spring in? The engine is from a John Deere 111 and was a year old when my father-in-law got it back in '83. He gave it to me about 3 years ago. I don't use it much.

The governor hadn't worked in approx. 7 years. The engine just ran at one speed which meant mowing was pretty strained. I tore the engine down last week and found out that the keeper on the governor arm had worn into the side of the block and locked the governor in place. I removed the sump, cleaned everything, installed a new governor and put everything back together. I ground some of the block away and added a washer between the keeper and the block to prevent it locking in place again. I cleaned and rebuilt the carb this past weekend but now the engine surges. I replaced the fuel pump last year.

With the throttle wide open (engine not running), I turned the governor clockwise as far as it would go and tightened the locking nut on the governor arm. Is this how it should be set? I'll go back and replace the seal this weekend. What do I use to remove the old one? Would a bad seal cause it to surge? BTW, the high rev screw (bottom of bowl) doesn't cause much change in the rpm's. Likewise for the idle screw on the top. I cleaned the carb very well with cleaner and blew everything out with air before installing the new parts. I didn't replace the venturi because I couldn't get the old one out. I made sure I cleaned it well and blew compressed air through it the best I could.

What do I need to look for to get this running better?

Thanks

 
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-21-07, 08:35 PM   #21  
I suggest removing the carb and soak it in a bath-type carb cleaner. Then blow out with compressed air, and install a kit. If yours has the all-meatl needle, then there is a seat in the fuel inlet of the carb where the tip of the needle goes. You can pick this out being careful to not put even a tiny scratch on the brass insert. Then install the new seat, with the ridge side towards the carburetor. Push it firmly in place with the blunt end of a small drill bit.

Whe you say you turned the governor, do you mean the arm on the side where the linkage connects, or do you mean the governor shaft that comes through the block?


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

God bless!

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-21-07, 09:29 PM   #22  
That was how I cleaned the carb. However, I didn't notice the seat. The green seal in the kit is flat on one side and rounded on the other. Are you saying the rounded side should be on top when the carb is attached to the engine? i.e. needle point goes into the flat side? Is the missing / bad seat causing the surges?

Holdng the linkage arm (attached to carb) all the way to the left (carb at full throttle), I rotated the governor shaft (goes through block) clockwise all the way and then tightened the linkage arm locking nut on the governor shaft. This was how someone told me to adjust the governor. Is this correct?

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-23-07, 04:48 AM   #23  
Please let me know if the round side or the flat side of the seal goes toward the needle point. Also, did I set the governor up right?

Thanks

 
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-24-07, 12:47 AM   #24  
On the governor adjsutment, are you sure it was to the left to get full throttle?

The seat has a bevel on the inner opening on one side. This goes toward the needle.


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

God bless!

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-24-07, 04:39 AM   #25  
yes, it was left.

The linkage arm that has a wire and spring to the carb stands straight up. I moved this counterclockwise until full throttle, rotated the governor shaft clockwise until it stopped (meaning the governor arm would have been pushed against the governor/splasher cap inside the engine) and then tightened the locking nut on the linkage arm.

Can you explain how it should be done?

 
hdtvluvr's Avatar
Member

Join Date: Dec 2004
Posts: 106

05-26-07, 11:01 AM   #26  
Was this correct? If not, what is the procedure?

Thanks!

 
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,574
GA

05-26-07, 10:57 PM   #27  
To my knowldege, you need to move the arm to the right, not the left, to get full throttle on that engine. Set it up just the way you did, except have the arm to the right.


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

God bless!

 
Search this Thread