Push mower Engine Speed Issues


Old 07-23-05, 02:24 PM
Thread Starter
Join Date: Sep 2000
Location: Columbia, SC
Posts: 219
Push mower Engine Speed Issues

B/s Quattro4.0 mounted on a Frigidaire/AYP push mower body. Purchased 1999. Engine series 10A902 Type 2121

Mower running rough and somewhat searching for speed. I had the speed issue once before. At that time, based on the recommendations here, a carb cleaning, new diaphragm and fresh gas did the trick perfectly.

So this time I bought a new diaphragm and diassembled the carb from the gas tank, only to find I purchased the wrong diaphragm...and the store is closed for the weekend. I careflully cleaned the carb and all of the surfaces and gingerly replaced the carb with the old diaphragm...so far so good.

Once everything was back together, I tried to start the mower. Usually it starts on pull one or two, but this time it took about seven pulls and a couple aadditional pumps from the primer. I also got a very strong pull back (enough to hurt my arm) on a couple of the start attempts. When it finally started, the idle speed was extremely high. There is no throttle on the mower so I tried to back it off adjusting the throttle shaft and the engine died. It restarted, but with the same issue. It would not settle into a good operating speed.

I took it apart again and this time noticed that the "governed Idle" spring (as opposed to the "governor spring", which appears to be in good repair and functioning properly) appeared broken and unattached to anything but the air vane link. I also noticed that the intake manifold had a chunk taken out of its end and had a hole (clearly damage) through about an inch back from the end and about 1-2 mm in diameter.


How much does the damaged goverened idle spring and manifold have to do with the problem?

What could have caused the damage to the intake manifold?

To what does the governed idle spring attach on the other end?

What do I do to fix the problem?

Please note:

The terms I used here came straight from the parts manual. I have limited experience with small engines and usually identify parts as "the round thing" or the "whozawhatsis." I do have pretty good computer skills and managed to locate the correct B/S parts list.

My wife has that "you know you shouldn't be messing with mechanical things" look on her face. Please help!

Stressed in South Carolina

Last edited by allenzachary; 07-23-05 at 02:27 PM. Reason: Unclear title
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Old 07-24-05, 12:34 AM
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Join Date: Jul 2001
Location: USA
Posts: 16,814
Hello Allen,

The broken tube and spring have everything to do with your problem. How they broke, I don't know, but they need to be fixed. The spring should connect to a notch on the metal bracket at the front of the engine just under the edge of the air cleaner housing. The intake tube needs to be replaced.
Old 07-24-05, 09:53 AM
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Just an added note to Cheese words,
Running the engine in this condition can cause fatal damage...quick! Once remedied check/change the engine oil.
Old 07-24-05, 10:10 AM
Thread Starter
Join Date: Sep 2000
Location: Columbia, SC
Posts: 219

I just ordered a new governed idlle spring and intake manifold. Should be here in time for next weekend.

I will change the oil as you recommend. The mower is disassembled in the garage. No worries as to running it.

As soon as I make the repairs, I will post the results. I'm sure the report wil be good.

Old 08-07-05, 08:58 AM
Thread Starter
Join Date: Sep 2000
Location: Columbia, SC
Posts: 219

The parts came in last week, I finally had a chance to work on it today.

Turns out that I ordered the wrong intake manifold. Apparenty BS redesigned the part and I chose the one with the round flange. When I took out the old one, it was square. They looked the same from the top. Shame on me for not disassembling further before I ordered the part.

Not to be defeated, I repaired the hole with JB Weld and it seems to be holding well. I didn't repair the chunk taken out of the end as it is inside the carb and will not allow leakage of fuel out or gair in (so it seems). I attached the new governed idle spring and reassembled the engine.

I checked the oil, it was at the low end of the operational scale and relatively clean. Plan to change the oil once this is up and running.

I startted the mower and it runs slow and rough. It idles slowly and inconsisitnently, not "hunting" but slightly faster then a little slower randomly. It never gets to a usable running speed. When I tug on the governor spring, the engine revs up; I let go, it drops.

The governor spring seems to be functional, but looks can be deceiving. It once was yellow, but now is rust colored with flecks of yellow paint.

Does the small chunk out of the end of the intake manifold make a difference? Will JB Weld work? (years ago I used it to hold together an attic fan assembly and it still works today). How about the governor spring?

I'm sweaty and frustrated. Any ideas?

(less of a mechanic than I thought)
Old 08-07-05, 10:44 PM
Join Date: Jul 2003
Location: ill.
Posts: 68
hole in take manifold causes major vacuum leak and engine to race like a helicopter which would stall on the first piece of grass you hit. if you dont fix it, and by some chance you could mow the dirt it would suck into your engine would eat your piston rings up. yes jb weld does work on all my small engine repairs. most noteworthy- i used it to secure a swimming valve seat on the exhaust valve. the new stuff does not work for me. the old 15 hr stuff works. i would use a piece of metal over the hole about same shape and size and use small amount of jbweld to secure it. let it sit overnite and ck it next day. jbweld on holes by itself does not last that long but when you bond it to fresh metal it works good. i have used aluminum and steel cut outs to perfection eliminating costly repairs.

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