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Engine kick backs - Cord Pulls Out Of Your Hand

#1

J

Jocke90

Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!


#2

S

slomo

Is there a blade on it?
What 2 vents are you talking about?
Post up model and serial numbers for the engine. Pictures are great too.

slomo


#3

Hammermechanicman

Hammermechanicman

Check your valve lash. The engine has a bump on the cam that acts as compression release. If lash is too wide it can cause kickback. If you pull the rope hard enough does the engine start and run?


#4

J

Jocke90

slomo said:
Is there a blade on it?
What 2 vents are you talking about?
Post up model and serial numbers for the engine. Pictures are great too.

slomo
Click to expand...
Sorry, I meant the intake valve and exhaust valve.
It's an old Stiga vertical cutter.
I have attached an image of the model and serial number.

Attachments





#5

Fish

Fish

You need to see if your flywheel is heavy enough. If the engine came off of a mower, the blade added weight and so the engines have a lighter flywheel.


#6

J

Jocke90

Hammermechanicman said:
Check your valve lash. The engine has a bump on the cam that acts as compression release. If lash is too wide it can cause kickback. If you pull the rope hard enough does the engine start and run?
Click to expand...
Do you mean the valve clearance? This engine does not compression release, it's quite old. Yes it does start but it kick backs very hard often when you pull it.


#7

J

Jocke90

Fish said:
You need to see if your flywheel is heavy enough. If the engine came off of a mower, the blade added weight and so the engines have a lighter flywheel.
Click to expand...
The engine is for a Stiga vertical cutter and it's been like this since we bought it.


#8

B

Born2Mow

Advanced ignition timing will have that effect at starting RPM. The ignition occurs before TDC, so the piston is pushed backwards. The pull cord ratchets are designed for one direction of rotation, so when the engine turns the opposite direction the cord gets abruptly yanked back.


#9

Hammermechanicman

Hammermechanicman

Fish said:
You need to see if your flywheel is heavy enough. If the engine came off of a mower, the blade added weight and so the engines have a lighter flywheel.
Click to expand...
130202 briggs will have a cast iron flywheel.


#10

Hammermechanicman

Hammermechanicman

Jocke90 said:
Do you mean the valve clearance? This engine does not compression release, it's quite old. Yes it does start but it kick backs very hard often when you pull it.
Click to expand...
The engine does have compression release. On the cam there is a the "easy spin" bump on the intake lobe. If the valve clearance is too wide it defeats it. Also, remove and decarbon the head. If it has heave deposits it can cause it to have higher compression. You can also check the intake valve operation to see if it stays just slightly open by a few thousandths on most of the compression stroke


#11

Fish

Fish

Let's see a pic of the whole piece of equipment. And engine.


#12

Q

QuantumLeap

It's most likely your fly will key is sheared causing a timing issue in the engine. Remove the top cover and then the nut that holds the flywheel on you might be able to see it. The key way and the flywheel will not be lined up with the key way on the crankshaft. You may have to remove the flywheel which is going to require putting the nut back on and hitting the crank on the threads with the nut guarding them and prying at the bottom. Be very careful They have specialty items for this called a knock if you would like to purchase it.


#13

S

sallyphilip

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Your engine is out of time check the key pin


#14

A

awkerper

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
I had the same kickback problem with a Tecumseh engine on a Coleman Powermate generator. The kickback was so violent that it damaged the recoil starter and I had to replace it.

The problem turned out to be the stud (bolt) that the exhaust valve rocker sits on. This bolt had started to work loose, jacking up the rocker and affecting the exhaust valve clearance and timing. Once I tightened it properly and readjusted the valve lash, the engine started normally and ran like a top. I used four thousandths of an inch for the valve lash.


#15

N

neely29607

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Most common problem is a loose blade. The blade acts as a flywheel which assist the engine in maintaining smooth forward motion. For nonbelievers, next time you have your blade off for sharpening, try to start it with the recoil rope. Be prepared for it to jerk the rope out of your hand and that hurts!^


#16

R

Rick42wood

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
I had this problem once and it turned out that the blade was just loose, and a similar problem with a chain saw was solved with a new spark plug and carb adjustment.


#17

S

Smitty154

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Cylinder is full of oil, hydrolocking, had same problem once, almost tore my fingers off snapping back. Someone stored mower standing up


#18

T

themikesell

I have the same problem with a Briggs from a Toro mower. I noticed someone mentioned a question of if there is a blade on or not. I've been trying g to start this with no blade and the kick back almost broke my fingers. I've been in pain e for a week now.

Is not having a blade on really that big of a deal?

Thanks


#19

Hammermechanicman

Hammermechanicman

The engine is a briggs 130202. This is a 5 hp horizontal shaft engine. I doubt if it has a loose blade.


#20

T

troynstan

Any chance the coil was installed upside down? This would cause a timing issue...


#21

Hammermechanicman

Hammermechanicman

themikesell said:
I have the same problem with a Briggs from a Toro mower. I noticed someone mentioned a question of if there is a blade on or not. I've been trying g to start this with no blade and the kick back almost broke my fingers. I've been in pain e for a week now.

Is not having a blade on really that big of a deal?

Thanks
Click to expand...
Some engines will start and run with no blade others won't. Most Briggs especially the old flat head engines will run wothout a blade. Most tecumseh engines won't.


#22

S

sallyphilip

awkerper said:
I had the same kickback problem with a Tecumseh engine on a Coleman Powermate generator. The kickback was so violent that it damaged the recoil starter and I had to replace it.

The problem turned out to be the stud (bolt) that the exhaust valve rocker sits on. This bolt had started to work loose, jacking up the rocker and affecting the exhaust valve clearance and timing. Once I tightened it properly and readjusted the valve lash, the engine started normally and ran like a top. I used four thousandths of an inch for the valve lash.
Click to expand...
out of time


#23

S

slomo

Carb might be dumping fuel into the cylinder = hydrolocking it. Pull the spark plug out and pull the rope. See if any liquids come out of the spark plug hole. If so, smell the liquid/s for identification.

slomo


#24

R

rainmaninwa

Pull the flywheel, If this is truly an old briggs with point type ignition, all you need to do is open up the point gap a bit. I had exactly the same problem with my garage sale 5 hp briggs. Probably needs new point/condender anyhow...


#25

D

docnhy

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Broke flywheel keyway


#26

G

Gord Baker

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Take the top off down to the Flywheel and check under that nut to be sure that the Key has not been partially sheared which puts it out of time enough to do that . Did you remove the flywheel and examine the key? Set coil at 0.300" from Flywheel. It could be valve timing


#27

Hammermechanicman

Hammermechanicman

Gord Baker said:
Set coil at 0.300" from Flywheel. It could be valve timing
Click to expand...
0.300" ???????


#28

G

glensto68

Most of the time the flywheel key is sheared when that begins to happen


#29

D

donens2018

Almost positive the problem is timing and the flywheel key. The key doesn't have to be sheared off. A slight offset of the key will result is this condition. Also check the flywheel keyway for rounded edges which can add to early key shearing, even with a new key. Sometimes some extra torque on the flywheel nut or rewind clutch can help prevent. If at anytime during startup, if backfires, this can cause the flywheel to shear again.


#30

R

rminnehan

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
The carburetor needle valve is not sealing tight and is letting gas go into the cylinder on top of the piston. When the piston reaches TDC (top dead center) the piston will not compress a liquid (the gasoline) as opposed to a vapor, which would be the gas/air mixture used for combustion. So when the piston reaches TDC the gasoline between the top of the piston and the head causes the piston to stop and it kicks back, jerking the starter line from your hand and damn near tearing your shoulder off. You need to do 3 things: First, fix the carburetor so the needle valve won't continue to leak. Second, remove the spark plug and pull the engine over. Be careful when doing this as gasoline will spew out the spark plug hole so try to put a rag or paper towel in front of the hole. Third, the gasoline that goes through the carburetor when the needle valve is leaking sometimes also goes into the crankcase and dilutes the oil in it so change the oil.


#31

Hammermechanicman

Hammermechanicman

The 130202 5hp briggs doesn't have a needle or a float in the carb.


#32

S

smallenginenovice

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...


#33

S

smallenginenovice

Check the keyway on the flywheel. If it's slightly twisted it throws the timing sequence off. This is very common if you hit anything with the blade it can shear the keyway. Pull the spark plug and ground it. Pull the nut off the flywheel and screw it on a couple of threads, pry up on the flywheel and whack the nut with a rubber hammer. Remove the nut and
you can see if the flywheel is lined up with the crank, then remove the flywheel and inspect the keyway. It should not be distorted. When you install it realize the keyway only locates position of the flywheel and it's the taper of the crank that holds it tight under torque. If that's not it check the valve lash and make sure the intake cam lobe is at the bottom position before adjustment. Some engines the lobe will drop slightly after top dead center as a compression release and if you don't find the bottom, you won't get the lash tight enough to reduce the compression at start. The comments on carbon are correct as that will cause an increase in compression and break your arm. You'll have to pull the head if that's the case.....good luck.


#34

Hammermechanicman

Hammermechanicman

You can check the key without removing the flywheel. You just need to access the top of the flywheel and look at it and the crank. Checking valve lash on the 5hp horizontal briggs requires removing the carb and gas tank which is a PITA. To access the valve spring chamber.
Or
The total lift on both the IN and EX cam lobes is .233". You can remove the head and measure total valve lift and the subtract that from .233" and you get the lash measurement.


#35

M

MNtractorGuy

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
Many years ago I had this with a mower. A friend said tighten the blade. I said it was and he said tighten it again. I did as advised and the the problem was fixed. I doubt that you have anything serious wrong and blades do come loose on occasion.


#36

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
0.300" ???????
Click to expand...

think on the 13's it's .010 to 0.014. thousandths of an inch.


#37

Hammermechanicman

Hammermechanicman

Scrubcadet10 said:
think on the 13's it's .010 to 0.014. thousandths of an inch.
Click to expand...
Yeah. I was wondering anyone else caught it.


#38

D

DPP

Jocke90 said:
Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!
Click to expand...
I had this problem and found it to be the carburetor. I had it off three times I finally replaced it and the problem went away. If I would of replaced the beetle and seat I think that would of fixed it.


#39

VRR.DYNDNS>BIZ

VRR.DYNDNS>BIZ

Well I can not believe all the long possibilities. The most likely issue is someone hit something and partially or completely sheared the flywheel key causing advanced timing and kickback. Pull the top down and remove flywheel nut and inspect the key very closely. If any, and even minor offset appearance, replace the key and see what you have.


#40

Hammermechanicman

Hammermechanicman

Lots of suggestions.
The engine is a 130202 horizontal engine. It has a pulsa jet carb so it doesn't have a float or needle and seat in the carb so it can't leak. It is not a push mower engine so it has a cast iron flywheel and it does not have a blade attached to the crankshaft. So the blade can't be loose.


#41

tagpop

tagpop

Make sure its a cast iron flywheel, folks do replace the cast iron with aluminum so this may have been done years ago. Second valve tappet clearance with piston just past top dead center on the compression stroke (intake valve just closed) should be about .007 intake or .011 exhaust. Check tappet clearance in that little box hole where the valve springs are. Make sure the intake valve and spring has not accidently been swapped with the exhaust valve and spring(they are different and have different specs/metals).


#42

S

Simonny9

Hi, I also have a Briggs & Stratton 5HP that is brand new, but the problem is the same - when I try to start it, the cord pulls back significantly, so I'm not sure what's wrong.


#43

S

slomo

Remove the head and check for excess carbon. This can lead to high compression ratios causing harder starting slash rope pulling.

slomo


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