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b+s engine running very slow

#1

A

asong

i have a b+s engine, and when i start it, it runs, then couple seconds later the engine just slows down and dies. i change the oil not too long ago, air filter looks fine.

there is this spring by the air filter, and when i poke it with a screw driver, it runs really fast, then when i let it go, it goes back to slow. maybe i have to replace the spring?


#2

pugaltitude

pugaltitude

Sounds like carburetor is the problem. Give it a clean.
What is the model, type and code of the engine?
Could be a diaphragm problem if fitted.
The spring is for the governor and controls rpm when engine running.


#3

EngineMan

EngineMan

You need to post up the engine number's and type, looks like that so called spring is off the governor.


#4

A

asong

hi and ty.

model number is: 11A-414D129

serial number is: 1F281K31342

it is a Yard Machines 4HP 21'' mower.


#5

A

asong

pugaltitude said:
Sounds like carburetor is the problem. Give it a clean.
What is the model, type and code of the engine?
Could be a diaphragm problem if fitted.
The spring is for the governor and controls rpm when engine running.
Click to expand...

hi.

i cleaned the carburetor not too long ago. it pumps well, so i dont think thats the problem.

i think the spring is messed up. not sure where its suppose to go. if i take a picture, can you see if its in the right place? ty.


#6

R

Rivets

You have to bend the bracket that the spring is attached to. Probably bent it in running into bushes.


#7

A

asong

Rivets said:
You have to bend the bracket that the spring is attached to. Probably bent it in running into bushes.
Click to expand...

hi. here is a picture.

100_1744.jpg


#8

R

Rivets

Can you take off that large spring and send another picture? There should only be one spring and I don't know what the small one is for. Thank you, I'll be here until 9PM central time.


#9

A

asong

hi.

im looking at the manual, and it says the remote throttle control may need adjustment. any idea how i can do this? ty.


#10

R

Rivets

Don't see a remote control hookup in your picture. Do you have a speed control on the handle?


#11

I

ILENGINE

First the throttle speed control is over rotated. the linkage between the governor arm and carb is backwards, and the throttle shaft needs to be flipped back up over the stud, so it rotated clockwise.

Rivets, the small spring is the auxillary governor spring.


#12

A

asong

Rivets said:
Don't see a remote control hookup in your picture. Do you have a speed control on the handle?
Click to expand...

no i don't.

but good news is, i fixed it up a bit, but this time the engine is running way too fast. im afraid it will explode. its late here, so i will post pictures tomorrow. ty.


#13

A

asong

ILENGINE said:
First the throttle speed control is over rotated. the linkage between the governor arm and carb is backwards, and the throttle shaft needs to be flipped back up over the stud, so it rotated clockwise.

Rivets, the small spring is the auxillary governor spring.
Click to expand...

hi. i will post pictures tomorrow. can u see if i do it correctly? ty.


#14

R

Rivets

Il you are right, I forgot about those on some engines. Thanks for correcting me.


#15

A

asong

hi. here is the adjustments i made.

100_1754.jpg



it runs great, but maybe too fast. how can i slow it down a tad?

also the springs dont seem like they do anything. there is no give or pull. its just there lol. do i need them?


#16

A

asong

ILENGINE said:
First the throttle speed control is over rotated. the linkage between the governor arm and carb is backwards, and the throttle shaft needs to be flipped back up over the stud, so it rotated clockwise.

Rivets, the small spring is the auxillary governor spring.
Click to expand...

hi,

can u tell me what the throttle speed control is? also, what is the governor arm? also the throttle shaft. ty.


#17

R

Rivets

Bending the tab on the right (oblong hole) in should slow the engine down. Engine speed should be 3200 RPM's. Those springs are governor control springs and because you don't know what they do, be very careful when adjusting them. Might be time to get a mechanic.


#18

A

asong

is it possible the engine can blow up? b/c i haven't seen this mower run this fast before.


#19

R

Rivets

Yes it can, or the blade may break if it is old. Had this happen on a lawn boy deflector just this summer. Lucky no one was hurt.


#20

A

asong

ty.

i guess i will play with the parts a bit more and see if it works. bed time now, will be back on tomorrow morning central time. ty.


#21

EngineMan

EngineMan

asong said:
hi. here is the adjustments i made.

100_1754.jpg



it runs great, but maybe too fast. how can i slow it down a tad?

also the springs dont seem like they do anything. there is no give or pull. its just there lol. do i need them?
Click to expand...

1 you have the small spring the wrong way round, take it off and turn it round.

2 the speed is preset, if running too fast close slow it down a little by turning the black part where the spring 1 right hand side of photo that I will post up...go's onto counterclockwise a little, that should slow down the speed.


#22

EngineMan

EngineMan

This is the photo

Attachments





#23

A

asong

EngineMan said:
1 you have the small spring the wrong way round, take it off and turn it round.

2 the speed is preset, if running too fast close slow it down a little by turning the black part where the spring 1 right hand side of photo that I will post up...go's onto counterclockwise a little, that should slow down the speed.
Click to expand...

hi, when i turn the black part counterclockwise, the springs dont do anything. i could throw out the springs and it will still be at the same places. also the black thing that i turned doesnt do anything either.


#24

A

asong

i will post a video tonite. see if i can get some help, ty.


#25

EngineMan

EngineMan

Is the governor blade moving (do you see it move when engine running)


#26

A

asong

EngineMan said:
Is the governor blade moving (do you see it move when engine running)
Click to expand...

hi, which is the governor blade?


#27

EngineMan

EngineMan

Its under the fan cover and it has the part that the two springs go onto.


#28

C

chance123

I haven't thought about this much, but it seems that the large spring is the flywheel brake spring. But if that were the case, it would be hard to pull and wouldn't even run because of the built in kill switch


#29

A

asong

hi,

i used the lawn mower today and cut my backyard. is it ok if there is no smoke or leaks? runs great, but im afraid it might explode one day lol.

i also opened the lid and checked the air fins. everything is clean.

i am wondering if i should just buy new springs? anyone know where i can buy them? ty.


#30

C

chance123

does this mower have a handle that you release to stop the engine? I guess my question is "how do you kill the engine?" I ask this because I was curious as to that mystry spring


#31

A

asong

chance123 said:
does this mower have a handle that you release to stop the engine? I guess my question is "how do you kill the engine?" I ask this because I was curious as to that mystry spring
Click to expand...

yes, it has a handle. i have to hold on to that to keep the mower running. if i let it go, the engine will stop.


#32

C

chance123

asong said:
yes, it has a handle. i have to hold on to that to keep the mower running. if i let it go, the engine will stop.
Click to expand...

OK then the spring around the flywheel is still intact. That is where your kill switch is


#33

A

asong

chance123 said:
OK then the spring around the flywheel is still intact. That is where your kill switch is
Click to expand...

what is a fly wheel?


#34

R

Rivets

I'm sorry to say this, but with the questions you are asking, you should stop trying to fix this mower and take it to a mechanic before you hurt yourself or some one around you. This is getting to the point where someone is going to get hurt.


#35

A

asong

first the engine was running so slow. then i made some adjustments and now it runs way too fast. i just need to slow it down just a tad. should i buy new springs?


#36

A

asong

i set up the springs exactly like this:

Picture3002.jpg


#37

A

asong

hi,

i got it fixed! basically i had to stretch both springs to make the engine run slower. runs great, i thought i had to buy a new mower. money saved!


#38

EngineMan

EngineMan

asong said:
hi,

i got it fixed! basically i had to stretch both springs to make the engine run slower. runs great, i thought i had to buy a new mower. money saved!
Click to expand...

You did'nt need to stretch any of the springs, if you look at your photo on the right hand side you will see that the lever has been push down, all you had to do is pull that back up and you will be able to turn it like I said counterclockwise to slow it down. and you will also see that the small spring has got play in it.


#39

EngineMan

EngineMan

Where the red arrow is, its that whats stopping it from turning.

Attachments





#40

hanyoukimura

hanyoukimura

That two spring setup is what a mower wit a throttle control, the tab people are pointing to is bent down at the factory to give it a fixed rpm. Later engines do away with that assembly as well as the larger spring. Basically, if you bent that tab up that assembly would pivot back and for and you could adjust rpm like you would if it had a throttle cable.

The smaller spring is the governor that sets the maximum rpm of the engine. This is the one you want to adjust to slow the engine down or speed it up only if its running too slow or too fast. Its very important that the engine isn't allowed to run too fast for too long or damage could occur.

To adjust max rpm you do not and should not stretch the spring, you simply bend the little tab it attaches to either toward (to decrease rpm) or away (to increase rpm) from the carburetor. Stretching the spring will result in the spring wearing out prematurely.

springs.jpg


Hopefully this clears things up.


#41

I

ILENGINE

hanyoukimura said:
That two spring setup is what a mower wit a throttle control, the tab people are pointing to is bent down at the factory to give it a fixed rpm. Later engines do away with that assembly as well as the larger spring. Basically, if you bent that tab up that assembly would pivot back and for and you could adjust rpm like you would if it had a throttle cable.

The smaller spring is the governor that sets the maximum rpm of the engine. This is the one you want to adjust to slow the engine down or speed it up only if its running too slow or too fast. Its very important that the engine isn't allowed to run too fast for too long or damage could occur.

To adjust max rpm you do not and should not stretch the spring, you simply bend the little tab it attaches to either toward (to decrease rpm) or away (to increase rpm) from the carburetor. Stretching the spring will result in the spring wearing out prematurely.

springs.jpg


Hopefully this clears things up.
Click to expand...

Wrong. If the two springs are not adjusted properly the engine will surge. The smaller spring is only used to get the last 200 rpm for max engine speed. Also the carb doesn't have an idle circuit in the carb, therefore will either surge below a certain rpm, or the engine just dies. The engine is not engineered to be a variable speed engine. the carb is for fixed speed only.

To properly set the engine rpm, you remove the tension from the small spring and bend the tab on the large spring to 200 rpm under max engine speed, then increase the tension on the small spring to set the final rpm.


#42

A

asong

hanyoukimura said:
That two spring setup is what a mower wit a throttle control, the tab people are pointing to is bent down at the factory to give it a fixed rpm. Later engines do away with that assembly as well as the larger spring. Basically, if you bent that tab up that assembly would pivot back and for and you could adjust rpm like you would if it had a throttle cable.

The smaller spring is the governor that sets the maximum rpm of the engine. This is the one you want to adjust to slow the engine down or speed it up only if its running too slow or too fast. Its very important that the engine isn't allowed to run too fast for too long or damage could occur.

To adjust max rpm you do not and should not stretch the spring, you simply bend the little tab it attaches to either toward (to decrease rpm) or away (to increase rpm) from the carburetor. Stretching the spring will result in the spring wearing out prematurely.

springs.jpg


Hopefully this clears things up.
Click to expand...

yes, i stretched out that small spring a bit and works great again! ty!


#43

A

asong

how do i know what rpm my mower is running at?


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