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25 HP Briggs

gpfister's Avatar

Join Date: Jul 2006
Posts: 1

07-15-06, 02:13 PM   #1  
25 HP Briggs

Hello All,


Engine: Briggs & Stratton
Model: 445777
HP: 25 VTech
Type: 0129
Trim: E1
Code: 000619YH
For: Craftsman Riding Lawnmower with a 46" deck.
Age: About 3 years old

I am the first and only owner of this engine.

Initial Problem:

Hunting and require of almost full choke to run at any rpm (i.e. running very lean)

What has been done:

Replaced fuel filter, fuel pump, all fuel lines from fuel tank to carb, plugs, and both air filters. Checked springs and linkage for choke, fuel, and govenor - all appears to be good.

Detailed indications,

Hunting only occurs 50% of the time, and can be corrected by adjusting choke. Only now choke is required at 95% to continue engine run when warm. Choke requirement increased gradualy over the past three years.

Recently, after inspecting govenor, (no changes or adjustments made) I ran on idile for 15 mins then run while cutting at full speed for 1/2 hour when motor suddenly ran at much higher rpm than ever. Throttled down to normal rpm, but still @ almost full choke. I've attempted to take apart float bowl to clean, however, the position that it's in makes it very difficult to remove without removing carb. I did notice that the breather tube is worn between air intake and engine (i.e. cracks). Could this cause the problem, or is this just part of it?

I'm not scared of anything, and will try anything at least once (within boundries of the bible), so any suggestions would be welcomed.

Thanks in advance!

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lexmarks567's Avatar
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Join Date: May 2006
Posts: 610

07-15-06, 02:29 PM   #2  
The breather tube could be the problem But im leaning towards thre carb or governer.try removing the carb and cleaning.Would not hurt anyway while your at it.Remove all the rubber parts of the carb and set them aside. soak the carb in a bath type cleaner following the directions.use compressed air to blow out all the holes.would you know what the max RPMS are for that engine.It would help toi know that before adjusting the governer.To fast and the engine could fly apart It sould say somewhere near the governer. (I'E do not excead 3000 RPM).

v8driver's Avatar

Join Date: Sep 2005
Posts: 767

07-15-06, 04:43 PM   #3  
Sounds like you do need to clean the carb, not hard to do or try.... Btw, this engine should be governed to run at 3,600 rpm. Btw, just go ahead and replace the breather tube..... those cracks may be letting dirt in (carb sucking at it)

cheese's Avatar
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Join Date: Jul 2001
Posts: 16,567

07-16-06, 08:49 PM   #4  
I agree, replace the breather tube because it will suck in dirt, but that's not causing the surging. The carb needs cleaning.

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