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Small Engines (Lawn Mowers, etc.)/Unattached Governor Spring and Gas Leakage 8 hp B&S


Linkage Spring
Linkage Spring  
Linkage Spring 2
Linkage Spring 2  

The following apply:

1. My 8 hp riding Snapper mower has been losing rpm's over the past 4 or 5 uses.

2. Recently it will not bring up enough rpm's to be used, it starts as well as it ever had but sounds flooded if throttle is raised over 10% or so.

3. After 2, an examination noted that the breather hose had become so loose it would not stay attached to it's carb end. Also a significant amount of gas was noted on the frame below the carb and also soaked into the pre-existing dirty linkage area and around the lower engine block, between the block and the carb. It created a black ooze. The dripping from the bottom of the intake end of the carb was not slow, but constant..even while not running.

4. After a new breather hose was installed evidence of a pretty large gas leak occurred on the floor under the mower. This amount of leakage had never happened before.

5. After 4, gas was observed in the oil.

6. Also noticed that the Governor Linkage Spring was unattached to anything, it was just coiled around the Governor Linkage..doing nothing.

7. Also noticed that the Governor itself barely turned until the throttle reached about 90%.

8. Gas tank has been drained and the process of cleaning off the black crud around the Linkages has begun.

I realize that these are a lot of issues. I just wondered if there might be a particular part or maintenance failure that caused them...and where to start a repair. The engine was a rebuild put on about 10 years ago. It is a summer use only mower and really not used very often.

model 191707
type 6019 01
code 90040512

262431 link governor          #201
261911 governor spring       #209


ANSWER: The leaky gas issue can be cured by:

a)  Rebuild the carb.  Replace the float and inlet needle.
b)  Install an inline fuel shut-off vavle and turn the gas OFF when you are done mowing.

Option b is quick, easy, cheap and works long as you remember to shut the fuel OFF when done mowing.

However, based on the age of the engine I would rebuild the carb, replacing the float and inlet needle and inlet needle seat, and install an inline fuel shut-off valve.

Rebuilding is easy, except for replacing the inlet needle seat.  You will need some special tools or get creative and source your own...most techs source there own from old sockets or small metal tubing.

Carb cleaning video on You Tube:

I could not find any videos on replacing the inlet needle seat.  It may not be necessary to replace, most shops don't replace, but on a 20+ year old mower I would replace the seat as well as the throttle wears and can cause all sorts of weird running problems.

As for the spring in the picture it connects between the governor arm and throttle connects/goes in the same hole as the throttle link/rod.  It's purpose is to minimize play on the throttle shaft reducing wear.  It does NOT effect engine speed...unless it gets in the way becasue it is broke.  Some Briggs engines have these springs and some don't.  If I have the option, I use or install the spring on all my engines.

The engine RPM is controlled by spring on the governor arm.  Follow the throttle cable down to the engine block...the gov arm and spring is behind the throttle plate.  DO NOT loosen or mess with the governor nut...AT ALL.  Make sure the governor spring is connected to the throttle plate and governor...just move the throttle and watch to see if the spring is connected.

To recap, you should rebuild the carb, install an inline fuel shut-off valve.  Make sure you change the oil, if it smells like or has gas in it or you will blow the eninge...seen this a lot.


---------- FOLLOW-UP ----------

QUESTION: (I found the reply link)

Thanks Eric.

That info did a good job of putting the possibly repairs into perspective for me. I wanted to get the carb off before I replied (although I don't see a specific reply link anymore).

1)I got the carb off without much trouble at all.

2)The bowl seemed to contain some fine grit which I think will clean up ok. It disassembled ok except for the shorter of the two nozzles, it's frozen. I have applied some penetrating oil and will let it soak overnight. The long nozzle was tight but it came out after a couple hours of pen~ oil.

3)I'm trying to figure out how to clean up the outside of the carb though. It's covered in a crust of saturated dust which has now dried out. I think a toothbrush would get it if was softened up. Can I soak the entire carb in something to loosen this stuff up. I don't want to use anything harmful.

4)Any guidelines to follow to clear the gas from the oil? Should I fill it with oil, then drain it all out? Should I crank it with the 'cleaner oil' in there before I drain it? I certainly don't want to damage the engine with the bad oil.


You can soak the carb  but I would just buy some degreaser and carb cleaner.  Spray the outside of the carb and use an old toothbrush to scrub.  You may have to spary, let it sit, scrub, and repeat several times to get it clean.

As for the oil, drain first, re-fill with new oil.  It takes just under one quart of SAE-30.  Just buy some cheap stuff at first because you are going to fill, run, drain, and re-fill.  I would do this twice.  On the third re-fill you may want to use some better oil.

The gas entered the engine through the carb.  The inlet needle did not seal and gas fill the carb to the point the gas ran into the engine.

You need to replace the inlet needle for sure.  I would also install an inline fuel shut-off valve and turn the fuel off every time you are done mowing.  This will ensure no gas enters the engine.

Make sure you blow compressed air, from and air compress, through all the carb holes to clean them.  You can use spray can carb cleaner to help clean the carb holes as well.


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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