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B&S won't start
#1
G
gbsk
G
gbsk
I have had a lawn mower for about 10 years and it has served me well. i have been unemployed for quite awhile so cannot afford to take it to a repair shop. It is a B & S engine with 3.5 HP and 20 ". Ace is the manufacturer. Model 95902; Type 3107 01; Code 93031605. I hope this is all you need.
I tried to start the mower after I fixed the cable and it would not start. I noticed the throttle did not move when I pulled the throttle lever either way. However, when I took the air filter off, it moved the mechanism with the spring, etc. Do I need to adjust something? I was thinking that the air filter or the screw that holds the cable to the shroud might be jamming the cable somehow. Also as noted below, maybe the spring is too loose on the carb but that would not affect the cable being off or on the shroud.
Last summer I replaced the gasket and diaphragm and cleaned out the carb and the diaphragm and gasket were in bad shape. It worked fine after that. This year, I did not replace the gasket and diaphragm. They both looked in great shape. There was just a slight bulge where the spring hits the diaphragm. I looked at a few videos this year when i cleaned the carb, air filter and gas tank using spray carb cleaner. I cleaned every orifice I found and wiped them well. I have only used the mower about 5 times since I replaced them. I know it has good compression because a small engine repairman said it did when asking about another mower. I took apart the starter assembly and put it back together using tranny fluid as lubricant for the spring. It pulls fine now but will not start. I know the bulb is okay since it squirts gas into the carb when pushing it. Last year I knew something was wrong when I pushed the bulb and there was no back pressure so after I replaced the the diaphragm, it worked fine. I always keep it in the shed and out of the weather. I did notice that earlier this year, I would have to pull the cord quite a few times to start it but after starting, it worked fine.
I noticed that the screw that holds the throttle cable to the shroud bit through the cable. I repaired the cable and it seems like it works fine when the cable is not attached to the mower. When I attach the cable to the mower, the throttle does not move the mechanism that moves the spring attached on top of the carburetor. Is there an exact place on the cable where the cable needs to attach to the shroud ? Is there another reason the mower will not start?
Thanks,
GB
I tried to start the mower after I fixed the cable and it would not start. I noticed the throttle did not move when I pulled the throttle lever either way. However, when I took the air filter off, it moved the mechanism with the spring, etc. Do I need to adjust something? I was thinking that the air filter or the screw that holds the cable to the shroud might be jamming the cable somehow. Also as noted below, maybe the spring is too loose on the carb but that would not affect the cable being off or on the shroud.
Last summer I replaced the gasket and diaphragm and cleaned out the carb and the diaphragm and gasket were in bad shape. It worked fine after that. This year, I did not replace the gasket and diaphragm. They both looked in great shape. There was just a slight bulge where the spring hits the diaphragm. I looked at a few videos this year when i cleaned the carb, air filter and gas tank using spray carb cleaner. I cleaned every orifice I found and wiped them well. I have only used the mower about 5 times since I replaced them. I know it has good compression because a small engine repairman said it did when asking about another mower. I took apart the starter assembly and put it back together using tranny fluid as lubricant for the spring. It pulls fine now but will not start. I know the bulb is okay since it squirts gas into the carb when pushing it. Last year I knew something was wrong when I pushed the bulb and there was no back pressure so after I replaced the the diaphragm, it worked fine. I always keep it in the shed and out of the weather. I did notice that earlier this year, I would have to pull the cord quite a few times to start it but after starting, it worked fine.
I noticed that the screw that holds the throttle cable to the shroud bit through the cable. I repaired the cable and it seems like it works fine when the cable is not attached to the mower. When I attach the cable to the mower, the throttle does not move the mechanism that moves the spring attached on top of the carburetor. Is there an exact place on the cable where the cable needs to attach to the shroud ? Is there another reason the mower will not start?
Thanks,
GB
#2
EngineMan
EngineMan
You say that you have good compression, and that you have cleaned out the carb, have you put a small amount of fuel into the spark plug hole or carb to see if it will fire..? try it.
If no spark or very little spark you will need to look at the ignition, that engine has internal breaker points, so you will have to take off the flywheel, first look for any rust on the pole magnet on the flywheel and on the legs of the armature, if any clean off with wet and dry. remove breaker cover and turn over engine (by hand) and better with spark plug removed to see if the points do open, then look for any signs of burning or pitting, and make sure that the small wire is still fitted to the top of the condenser.
If you do need to reset the points they are set at .020" (05mm) and make sure its right..! points set too wide will advance spark timing and will also give kick back when starting, and if they are gapped too close will retard spark timing and decrease engine power.
If you don't have a parts manual for that engine you can look up one over web, if you can't find one PM me with a e-mail address and I'll send it, and any info that you may need to you.
If no spark or very little spark you will need to look at the ignition, that engine has internal breaker points, so you will have to take off the flywheel, first look for any rust on the pole magnet on the flywheel and on the legs of the armature, if any clean off with wet and dry. remove breaker cover and turn over engine (by hand) and better with spark plug removed to see if the points do open, then look for any signs of burning or pitting, and make sure that the small wire is still fitted to the top of the condenser.
If you do need to reset the points they are set at .020" (05mm) and make sure its right..! points set too wide will advance spark timing and will also give kick back when starting, and if they are gapped too close will retard spark timing and decrease engine power.
If you don't have a parts manual for that engine you can look up one over web, if you can't find one PM me with a e-mail address and I'll send it, and any info that you may need to you.
#3
scott47429
scott47429
Have you checked to see if your getting spark also try spring some carb cleaner or starting fluid into the carb then see if it will start if not then you may have a spark problem if so then you have a fuel problem if this is a plastic tank mounted carb it probably needs replaced if it don't start then look at the kill switch to see if its working right let us know what you find out
#4
G
gbsk
G
gbsk
I looked online for the manual but could not find one. I would appreciate it if you would send it to me.
Thank you.
Thank you.
You say that you have good compression, and that you have cleaned out the carb, have you put a small amount of fuel into the spark plug hole or carb to see if it will fire..? try it.
If no spark or very little spark you will need to look at the ignition, that engine has internal breaker points, so you will have to take off the flywheel, first look for any rust on the pole magnet on the flywheel and on the legs of the armature, if any clean off with wet and dry. remove breaker cover and turn over engine (by hand) and better with spark plug removed to see if the points do open, then look for any signs of burning or pitting, and make sure that the small wire is still fitted to the top of the condenser.
If you do need to reset the points they are set at .020" (05mm) and make sure its right..! points set too wide will advance spark timing and will also give kick back when starting, and if they are gapped too close will retard spark timing and decrease engine power.
If you don't have a parts manual for that engine you can look up one over web, if you can't find one PM me with a e-mail address and I'll send it, and any info that you may need to you.
#5
EngineMan
EngineMan
PM me with e-mail address
#7
EngineMan
EngineMan
File's have been sent...:thumbsup:
#8
G
gbsk
G
gbsk
Thanks Tony for sending the parts manual. I did what you said about cleaning the points, Howeve, I took off the flywheel but I do not think this engine has points. I looked at this video. HOW TO ADJUST The Points on 3.5 HP BRIGGS & STRATTON Engine - YouTube It shows in the video that there are 2 screws to take off under the flywheel to expose the condenser and points. It looks like mine is an aluminum base with no screws in it. Here is the information again. Model 95902; Type 3107 01; Code 93031605.I cleaned out the carburetor with carb cleaner. The diaphragm looks good and is a year old. When I press the bulb to inject gas in the carb, it squirts out fine. I put some gas on the end of a spark plug but it still will not start. I don't have any way to spray gas in the carb. It has a new spark plug. It has good compression.
#9
EngineMan
EngineMan
Is this the one...? make sure you have a spark, also make sure that the stop wire (356) page 7 is in the switch stop (621) and is not going to earth (ground) if you have no spark test the coil.
Attachments
#10
G
gbsk
G
gbsk
The numbers correspond. However, it is hard to tell by a diagram. The flywheel guard I have is a grill on the top. The one in the diagram is one that goes around the perimeter. I will try to find out what the stop wire, the switch stop and where the coil are located and get back to you.
Is this the one...? make sure you have a spark, also make sure that the stop wire (356) page 7 is in the switch stop (621) and is not going to earth (ground) if you have no spark test the coil.
#11
G
gbsk
G
gbsk
I do get a spark. Ithought if you do NOT get a spark, then the check the stop switch and stop wire. What else can it be? Thank you.
Is this the one...? make sure you have a spark, also make sure that the stop wire (356) page 7 is in the switch stop (621) and is not going to earth (ground) if you have no spark test the coil.
#12
EngineMan
EngineMan
You need compression, fuel and then a spark, you say you have good compression and fuel into the carb, you say you have put fuel into the venturi and into the spark plug hole but it will not fire up, so check them again making sure you don't have a partly sheared flywheel key.
#13
D
DaveTN
D
DaveTN
In one of your earlier posts you said you saw the primer bulb squirt fuel into the carburetor, and that it still would not fire off. So it has to be something in the ignition. Possibly the coil wire (kill switch wire) grounding out between the coil and the switch. If it doesn't have points that would kill the fire, it would have to be in the wire. Either that or the whole coil is bad. Try pulling the wire off the clip on the coil and see if it gets fire. Could also be an internal break in the kill switch wire. When you said: "I repaired the cable and it seems like it works fine when the cable is not attached to the mower. When I attach the cable to the mower, the throttle does not move the mechanism that moves the spring attached on top of the carburetor." That tells me that the throttle shaft itself may be stuck! Have you physically tried to move the throttle plate on top of the carburetor? Try squirting some WD-40 on it and move it back and forth gently. Might free up. Hope this helps.
#14
C
chance123
There are so many variables here so since you are getting spark, I'll start by asking "are you trying to start it with the air filter "and" air filter screw removed? With "some" of these carbs to be test run WITHOUT the air filter, you still need the air filter screw screwed in. (that screw goes through the choke butterfly and into your tank) Otherwise fuel from the tank will enter the carb through that screw hole and give too much fuel entering the engine and flooding it out. Try putting that screw in and starting it. If there is already too much fuel in the engine, take a small screw driver in the throat of the carb to restrict the choke from closing. You "might" have to pull it many times to eliminate that excess fuel. See if it wicks up. Wait a minute. Did you say it has a primer bulb? if so, disregard.
C
chance123
I do get a spark. Ithought if you do NOT get a spark, then the check the stop switch and stop wire. What else can it be? Thank you.
There are so many variables here so since you are getting spark, I'll start by asking "are you trying to start it with the air filter "and" air filter screw removed? With "some" of these carbs to be test run WITHOUT the air filter, you still need the air filter screw screwed in. (that screw goes through the choke butterfly and into your tank) Otherwise fuel from the tank will enter the carb through that screw hole and give too much fuel entering the engine and flooding it out. Try putting that screw in and starting it. If there is already too much fuel in the engine, take a small screw driver in the throat of the carb to restrict the choke from closing. You "might" have to pull it many times to eliminate that excess fuel. See if it wicks up. Wait a minute. Did you say it has a primer bulb? if so, disregard.
#15
G
gbsk
Thank you very much for the answer. I took the carburetor apart and cleaned it with carb cleaner. I am getting a spark as my wife looked before. The flywheel key was not sheared. I used fine metal sandpaper to clean the magnet on the flywheel and the two parts on the magneto that come into contact with the flywheel. The flywheel spins fine as I left a gap between the magneto and flywheel of business card thickness. I put everything together and pulled the starting rope and it pulled out but would not recoil. This was the very original problem but it happened again. When I take the shroud off, the rope recoils right away. When it is on the shaft that the flywheel is on, it will not recoil. How do I fix this? I already took the spring out earlier and put the starter mechanism back together so I know that is not the problem. It is just when the shroud is on the flywheel.
G
gbsk
The numbers correspond. However, it is hard to tell by a diagram. The flywheel guard I have is a grill on the top. The one in the diagram is one that goes around the perimeter. I will try to find out what the stop wire, the switch stop and where the coil are located and get back to you.
Thank you very much for the answer. I took the carburetor apart and cleaned it with carb cleaner. I am getting a spark as my wife looked before. The flywheel key was not sheared. I used fine metal sandpaper to clean the magnet on the flywheel and the two parts on the magneto that come into contact with the flywheel. The flywheel spins fine as I left a gap between the magneto and flywheel of business card thickness. I put everything together and pulled the starting rope and it pulled out but would not recoil. This was the very original problem but it happened again. When I take the shroud off, the rope recoils right away. When it is on the shaft that the flywheel is on, it will not recoil. How do I fix this? I already took the spring out earlier and put the starter mechanism back together so I know that is not the problem. It is just when the shroud is on the flywheel.
#16
EngineMan
EngineMan
The manual that I have for that model is only showing with elc start, so will need to see a photo of the one you have to be of any help to you. if you can post a photo showing underside.
#17
C
chance123
OK this is an easy one. First off, when the shroud is off, does that square recoil clutch rotate freely? (it will only rotate in one direction) I am assuming that you have that type of recoil. If that's the case, install the shroud pull the rope out and if it doesn't go back in, leave the rope out. Then tap with a hammer all around the upper part of the shroud where the rope goes in. When you tap the sweet spot, the rope should go back in. remember that sweet spot and repeat. It sounds like your shroud might have been hit and threw it out of alignment. It doesn't take much to do this which will cause your problem.
C
chance123
When it is on the shaft that the flywheel is on, it will not recoil. How do I fix this? I already took the spring out earlier and put the starter mechanism back together so I know that is not the problem. It is just when the shroud is on the flywheel.
OK this is an easy one. First off, when the shroud is off, does that square recoil clutch rotate freely? (it will only rotate in one direction) I am assuming that you have that type of recoil. If that's the case, install the shroud pull the rope out and if it doesn't go back in, leave the rope out. Then tap with a hammer all around the upper part of the shroud where the rope goes in. When you tap the sweet spot, the rope should go back in. remember that sweet spot and repeat. It sounds like your shroud might have been hit and threw it out of alignment. It doesn't take much to do this which will cause your problem.
#18
G
gbsk
G
gbsk
Thank you for the reply. The recoil clutch rotates freely in one direction. I put the shroud on and tapped the upper part of the shroud but nothing happened. I did not want to do it more or harder because I was afraid of bending the metal.
OK this is an easy one. First off, when the shroud is off, does that square recoil clutch rotate freely? (it will only rotate in one direction) I am assuming that you have that type of recoil. If that's the case, install the shroud pull the rope out and if it doesn't go back in, leave the rope out. Then tap with a hammer all around the upper part of the shroud where the rope goes in. When you tap the sweet spot, the rope should go back in. remember that sweet spot and repeat. It sounds like your shroud might have been hit and threw it out of alignment. It doesn't take much to do this which will cause your problem.
#19
C
chance123
When you tap this part as I explained, don't tap down, tap inward toward the center.
C
chance123
Thank you for the reply. The recoil clutch rotates freely in one direction. I put the shroud on and tapped the upper part of the shroud but nothing happened. I did not want to do it more or harder because I was afraid of bending the metal.
When you tap this part as I explained, don't tap down, tap inward toward the center.
#20
G
gbsk
G
gbsk
Chance,
Thank you for the response. I got a rubber mallet and tapped the sides of the shroudtowards the center as you indicated. Nothing happened. I thought I tapped fairly hard. Do I need to tap harder? I don't want to make it owrse.
Thanks
Thank you for the response. I got a rubber mallet and tapped the sides of the shroudtowards the center as you indicated. Nothing happened. I thought I tapped fairly hard. Do I need to tap harder? I don't want to make it owrse.
Thanks
When you tap this part as I explained, don't tap down, tap inward toward the center.
#21
C
chance123
If that square shaft under the flywheel shroud moves freely (in one direction), and when the shroud is off the rope goes in and out freely, once you install the shroud, pull the rope out. You say it does not retract, so this indicates that the top of the shroud is warped. As you hit inward with a mallet all around your starter (the part that covers the pulley), and when you hit the sweet spot, the rope should retract. "That" is the spot where you need to keep hitting until the starter functions correctly.
C
chance123
Chance,
Thank you for the response. I got a rubber mallet and tapped the sides of the shroudtowards the center as you indicated. Nothing happened. I thought I tapped fairly hard. Do I need to tap harder? I don't want to make it owrse.
Thanks
If that square shaft under the flywheel shroud moves freely (in one direction), and when the shroud is off the rope goes in and out freely, once you install the shroud, pull the rope out. You say it does not retract, so this indicates that the top of the shroud is warped. As you hit inward with a mallet all around your starter (the part that covers the pulley), and when you hit the sweet spot, the rope should retract. "That" is the spot where you need to keep hitting until the starter functions correctly.