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fuel delivery problem?
#1
M
mowerboy
M
mowerboy
I got a Craftsman (550 series Briggs and Stratton engine) push mower that hasn't been used in a few years. I changed the oil, air filter, and spark plug. At first I couldn't get it to start, but then I used a little starting fluid and got it going. Now I am having a strange problem. The mower keeps on stalling. I will run for may 30 seconds or so before it stalls. I discovered that if I hold the mower at a 45 degree angle to the left (gas tank above engine) then it will run without stalling. I can keep it running like that for a long time, but the minute that I lower it back flat on the ground, it stalls again. It seems to me to be some sort of fuel delivery problem, but I don't know where to start. I have never worked on mower engines before. Anyone have any ideas?
Thanks!
Thanks!
#2
BKBrown
BKBrown
If it had not been run in quite a while, it probably has gunk in the Carb. - tilting it may allow the float to let some fuel past the main jet needle valve. If you know anything about it, depending on the mower, you can take the bowl off the carb and clean it out using spray carb cleaner - make sure to take out the main needle valve and clean the jet.
If you don't know enough or don't feel comfortable doing the above, Get some Seafoam or 2X Gumout and put it in the gas tank (correct mix strength) with fresh Gas - make it run for a while as you have stated. The cleaner in the gas may solve the problem.
If you don't know enough or don't feel comfortable doing the above, Get some Seafoam or 2X Gumout and put it in the gas tank (correct mix strength) with fresh Gas - make it run for a while as you have stated. The cleaner in the gas may solve the problem.
#3
M
mowerboy
Thanks for the advice. I would probably try this before attempting to take apart the carburetor. Although I am pretty handy, I have never done something like that before.
My only hesitation is from what is says in the manual:
"Never use engine or carburetor cleaner products in the fuel tank or permanent damage may occur."
Do you think that I really have to worry about this? Why would they say this?
Thanks.
p.s. I did use fresh gas, dumping out the old gas first.
M
mowerboy
If you don't know enough or don't feel comfortable doing the above, Get some Seafoam or 2X Gumout and put it in the gas tank (correct mix strength) with fresh Gas - make it run for a while as you have stated. The cleaner in the gas may solve the problem.
Thanks for the advice. I would probably try this before attempting to take apart the carburetor. Although I am pretty handy, I have never done something like that before.
My only hesitation is from what is says in the manual:
"Never use engine or carburetor cleaner products in the fuel tank or permanent damage may occur."
Do you think that I really have to worry about this? Why would they say this?
Thanks.
p.s. I did use fresh gas, dumping out the old gas first.
#4
BKBrown
BKBrown
The only reason I can think of for them to caution against cleaner is that some people use it mixed too strong or straight. If the can states the mixture or that it treats 15 gal. only use the ammount that would equal what your tank holds. I've never seen Seafoam hurt an engine or Carb.
#5
K
KennyV
K
KennyV
do you have a plastic fuel tank or carb?.. . some cleaners are not good for plastics...
is this the primer bulb OR choke type carb?
If it has a fuel tank connected to the carb with a hose, then BKBrown has the most likely problem...
but if this has the carb bolted directly to the tank... you may find that the diaphragm on the carb is needing replaced, (won't pump fuel up into the carb), or the fuel pick up tube that goes into the tank is blocked with gunk... Both relatively easy fixes. :smile:KennyV
is this the primer bulb OR choke type carb?
If it has a fuel tank connected to the carb with a hose, then BKBrown has the most likely problem...
but if this has the carb bolted directly to the tank... you may find that the diaphragm on the carb is needing replaced, (won't pump fuel up into the carb), or the fuel pick up tube that goes into the tank is blocked with gunk... Both relatively easy fixes. :smile:KennyV
#6
BKBrown
BKBrown
I'm sure some parts are affected by cleaners and I haven't seen (worked on) one that has the diaphragm on the tank. If using a little cleaner doesn't work - post again with a better description of the model (pictures help) and I'm sure you can get better advice than I have given.
#7
K
KennyV
I think about any of the modern day cleaners are safe on any of the plastics ...
some of the older cleaners might be a little too 'good' and melt things... but the things your apt to find should be safe... :smile:KennyV
K
KennyV
I'm sure some parts are affected by cleaners and I haven't seen (worked on) one that has the diaphragm on the tank. If using a little cleaner doesn't work - post again with a better description of the model (pictures help) and I'm sure you can get better advice than I have given.
I think about any of the modern day cleaners are safe on any of the plastics ...
some of the older cleaners might be a little too 'good' and melt things... but the things your apt to find should be safe... :smile:KennyV
#9
W
wildbill
W
wildbill
I agree with BKBrown in that properly mixed cleaners will not hurt anything. All the carb cleaner spray cans have plastic nozzles, duh. Here is a quick trick I use all the time:
Go to a NAPA or similar auto parts store and purchase a spray can of Carb Cleaner. The liquid inside will make the parts clean and shine in a jiffy, and I'm talking seconds. It will dissolve the varnish deposits inside the carb, and it sounds like these deposits are the culprit.
- Drain the gas tank.
- Remove the gas line from tank connection, leave the line attached to the carb. Drain the gas from the line as well.
- Use the plastic spout attached to the Carb Cleaner and very slowly press the nozzle to fill the gas line from where it attached to the tank, fill up the line. This will put the cleaner into the carb. Be generous.
- Now reattach the gas line to the tank. Pour in a cup or so of gas into the tank.
-Take a smoke, go get a drink, or in some method of your choosing wait a couple minutes. The carb cleaner evaporates very quickly and works quickly.
- Crank it up.
- Usually one treatment is enough, sometimes it may take 2-3 treatments.
Note that it sounds like your main jet has some varnish in it. If a couple treatments do not work, just remove the bowl from the bottom of the carb. The main jet is located in the 'tube' that comes down the farthermost from the carb body.
Go to a NAPA or similar auto parts store and purchase a spray can of Carb Cleaner. The liquid inside will make the parts clean and shine in a jiffy, and I'm talking seconds. It will dissolve the varnish deposits inside the carb, and it sounds like these deposits are the culprit.
- Drain the gas tank.
- Remove the gas line from tank connection, leave the line attached to the carb. Drain the gas from the line as well.
- Use the plastic spout attached to the Carb Cleaner and very slowly press the nozzle to fill the gas line from where it attached to the tank, fill up the line. This will put the cleaner into the carb. Be generous.
- Now reattach the gas line to the tank. Pour in a cup or so of gas into the tank.
-Take a smoke, go get a drink, or in some method of your choosing wait a couple minutes. The carb cleaner evaporates very quickly and works quickly.
- Crank it up.
- Usually one treatment is enough, sometimes it may take 2-3 treatments.
Note that it sounds like your main jet has some varnish in it. If a couple treatments do not work, just remove the bowl from the bottom of the carb. The main jet is located in the 'tube' that comes down the farthermost from the carb body.
#10
M
mowerboy
M
mowerboy
Re: fuel delivery problem? - NOW Throttle problem!
Well, finally found some time to work on the mower a little.
btw, this model has the carb screwed directly onto to gas tank.
So I first tried some seafoam in the gas tank. That didn't do anything, so took off the gas tank, removed the carb and cleaned it out with carb cleaner. It wasn't really that dirty at all. That didn't help either, same problem. I was almost about to give up, but then I discovered that if I manually open up the throttle, the engine runs perfectly! This model does not have an adjustable throttle, it's supposed to be set at the factory. It seems to be controlled by some mechanism inside the crankcase. I don't know how it is supposed to work, but whatever it is, it is not working properly right now. I managed to get the mower running and mow my lawn by attaching a hanger to the throttle linkage and holding the throttle open. But I don't think this is a long term solution because it runs too fast like that. It's hard to fine tune the speed this way. I would like to get the throttle control fixed so that it runs like it's supposed to. Does anyone know how to do this? Preferably without taking apart the whole engine which I am not that interested in doing.
Thanks for your help!
Well, finally found some time to work on the mower a little.
btw, this model has the carb screwed directly onto to gas tank.
So I first tried some seafoam in the gas tank. That didn't do anything, so took off the gas tank, removed the carb and cleaned it out with carb cleaner. It wasn't really that dirty at all. That didn't help either, same problem. I was almost about to give up, but then I discovered that if I manually open up the throttle, the engine runs perfectly! This model does not have an adjustable throttle, it's supposed to be set at the factory. It seems to be controlled by some mechanism inside the crankcase. I don't know how it is supposed to work, but whatever it is, it is not working properly right now. I managed to get the mower running and mow my lawn by attaching a hanger to the throttle linkage and holding the throttle open. But I don't think this is a long term solution because it runs too fast like that. It's hard to fine tune the speed this way. I would like to get the throttle control fixed so that it runs like it's supposed to. Does anyone know how to do this? Preferably without taking apart the whole engine which I am not that interested in doing.
Thanks for your help!
#11
K
KennyV
K
KennyV
Re: fuel delivery problem? - NOW Throttle problem!
That is the governor... it normally holds the throttle open, then as engine RPM increases it will start to close the throttle plate... Is the linkage hooked up properly, (has it ever been removed, and replaced wrong?)
:smile:KennyV
It seems to be controlled by some mechanism inside the crankcase. I don't know how it is supposed to work, but whatever it is, it is not working properly right now.
Does anyone know how to do this? Preferably without taking apart the whole engine which I am not that interested in doing.
That is the governor... it normally holds the throttle open, then as engine RPM increases it will start to close the throttle plate... Is the linkage hooked up properly, (has it ever been removed, and replaced wrong?)
:smile:KennyV
#12
M
mowerboy
Yes, it is the governor. Thank you.
I did a little research and found this page on the B&S website: Governor System FAQ that explains how it works. So I went back to look at my mower and voilà :biggrin:! For some reason, the spring that is supposed to pull the throttle open is completely missing on my mower! I got this mower used, I guess the previous owner must have played around with it for some reason. So now I will just have to buy the spring, and hopefully it will be up and running.
Thanks for your help guys!
M
mowerboy
That is the governor... it normally holds the throttle open, then as engine RPM increases it will start to close the throttle plate... Is the linkage hooked up properly, (has it ever been removed, and replaced wrong?)
:smile:KennyV
Yes, it is the governor. Thank you.
I did a little research and found this page on the B&S website: Governor System FAQ that explains how it works. So I went back to look at my mower and voilà :biggrin:! For some reason, the spring that is supposed to pull the throttle open is completely missing on my mower! I got this mower used, I guess the previous owner must have played around with it for some reason. So now I will just have to buy the spring, and hopefully it will be up and running.
Thanks for your help guys!
#13
reynoldston
reynoldston
The briggs and stratton engines I have worked on have a fuel pickup tube that gos into the gas tank. Make sure this has not falled off. Seeing it runs ok when you tilt it ,it sure sound like this is the case?
#14
M
mowerboy
Read my latest post, you'll see that the problem is solved.
It must be that tilting the mower at the correct angle caused the governor mechanism (which uses gravity and centrifugal force) to keep the throttle open even without the spring in place.
M
mowerboy
The briggs and stratton engines I have worked on have a fuel pickup tube that gos into the gas tank. Make sure this has not falled off. Seeing it runs ok when you tilt it ,it sure sound like this is the case?
Read my latest post, you'll see that the problem is solved.
It must be that tilting the mower at the correct angle caused the governor mechanism (which uses gravity and centrifugal force) to keep the throttle open even without the spring in place.
#15
H
hankg
H
hankg
Re: fuel delivery problem? - NOW Throttle problem!
I agree, the carb will need cleaning. If I may offer a bit of advice. Your engine has a oil SPLASH! lubricating system. When you tip the machine to the rear or to far off level, you seriously disrupt this splash system. The result of that is a wiped out cylinder , rings, piston or even all three. Don't run it in this manner to trouble shoot, you will pay a price for doing so.
Well, finally found some time to work on the mower a little.
btw, this model has the carb screwed directly onto to gas tank.
So I first tried some seafoam in the gas tank. That didn't do anything, so took off the gas tank, removed the carb and cleaned it out with carb cleaner. It wasn't really that dirty at all. That didn't help either, same problem. I was almost about to give up, but then I discovered that if I manually open up the throttle, the engine runs perfectly! This model does not have an adjustable throttle, it's supposed to be set at the factory. It seems to be controlled by some mechanism inside the crankcase. I don't know how it is supposed to work, but whatever it is, it is not working properly right now. I managed to get the mower running and mow my lawn by attaching a hanger to the throttle linkage and holding the throttle open. But I don't think this is a long term solution because it runs too fast like that. It's hard to fine tune the speed this way. I would like to get the throttle control fixed so that it runs like it's supposed to. Does anyone know how to do this? Preferably without taking apart the whole engine which I am not that interested in doing.
Thanks for your help!
I agree, the carb will need cleaning. If I may offer a bit of advice. Your engine has a oil SPLASH! lubricating system. When you tip the machine to the rear or to far off level, you seriously disrupt this splash system. The result of that is a wiped out cylinder , rings, piston or even all three. Don't run it in this manner to trouble shoot, you will pay a price for doing so.