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Engine wont prime gas

#1

R

rigoletto

people,

have a push mower, Troy Bilt, 6.75HP B&S engine, and red push primer button appears OK (pressed it onto my palm, and felt to create pressure), cleaned carb well, Ive cleaned many carbs before, but geez- primer does not suck in any gas. You can feel it and hear it when it sucks in, and it does NOT suck in any primer gas.

I did replace the paper gasket behind the black plastic housing too, just in case, but it was a waste of $2. Still no sucking gas. ideas appreciated.


#2

R

rigoletto

Oh- forgot to mention, I sprayed some ether in carb to start it, and it ran great. Ran for a few minutes, so gas is good, not old, and all fires up well in engine. Shut it down, waited a minute, pushed the primer button , no prime action. No start. Starts only with ether. Prime still no works.


#3

ILENGINE

ILENGINE

Without knowing the model number I am assuming you have the flat paper filter in front of the carb, with the primer located in the front/side of the rear air filter mounting piece. That type of primer doesn't pump gas, it pushed air into the carb to force the fuel up into the venturi of the carb. It is common for the cover to warp preventing a proper air seal between the cover and the carb. I usually double gasket that area and it fixes it most of the time.


#4

R

rigoletto

Without knowing the model number I am assuming you have the flat paper filter in front of the carb, with the primer located in the front/side of the rear air filter mounting piece. That type of primer doesn't pump gas, it pushed air into the carb to force the fuel up into the venturi of the carb. It is common for the cover to warp preventing a proper air seal between the cover and the carb. I usually double gasket that area and it fixes it most of the time.

thnaks. Right- I have the pleated paper filter in front, and I can ad the original gasket to make extra paddding- I will try it. But, I doubt it will work, cuz it is plastic, and warpage seems unlikely- it's not like its an aluminum head on an engine where slight warpage is a big factor(?). I cranked down on the 3 bolts to seat that plastic housing. Still, good tip, worth a try.


#5

ILENGINE

ILENGINE

Actually overtightening of the bolts is what causes the cover to deform preventing a proper air tight seal.


#6

R

Rivets

You may want to check your float level. I have found that if the float is not adjusted properly (set in a lean running condition) the primer does not have enough push to push fuel up the nozzle. I try to set the level slightly rich.


#7

R

rigoletto

Actually overtightening of the bolts is what causes the cover to deform preventing a proper air tight seal.

OK, then I should try to not overtighten. But how does one know(?)

Update: added the 2nd gasket, and no difference. I did notice that the primer bulb does "push" air into the crescent shaped "slit" molded into the housing (soap bubble test, then dry it off). Also, with paper filter removed, allowing one to see directly into the carb orfice, gas accumulates as seepage, then drips downward slopping all over the housing of course.

OH- I did thread a fine wire into the carb orfice where the priming gas is supposed to seep into- no blockage down there, I believe, since the wire inserted about a full inch -1-1/4.


#8

R

rigoletto

You may want to check your float level. I have found that if the float is not adjusted properly (set in a lean running condition) the primer does not have enough push to push fuel up the nozzle. I try to set the level slightly rich.

OK, Riv, but do I simply remove gas line, gently remove carb, and remove bowl to check level? How does that work because, every time I unscrew that bowl nut underneath most the gas drips out............(scratching scalp, left elbow resting on desk........)


#9

R

Rivets

First, if you see fuel in the air horn when priming, there is no need to check the float level. Try this trick. Cut a stiff piece of paper or thin cardboard to a size that you can cover the carb throat with the air filter back still in place. Prime unit three times, place paper over carb throat, have someone start the engine. If the engine starts and continues to run when you remove the paper, I'm betting you have old fuel which is not volatile enough to burn at low RPM's.


#10

B

bertsmobile1

OK, Riv, but do I simply remove gas line, gently remove carb, and remove bowl to check level? How does that work because, every time I unscrew that bowl nut underneath most the gas drips out............(scratching scalp, left elbow resting on desk........)

If you do it regularly you get a second bowl nut, drill a hole in it and force some trimmer fuel line in there about 4" to 6" long.
replace the bowl hold the line up alongside the carb and you should see the level rise then stop just short of the floor of the carb throat.


#11

B

bertsmobile1

OK, then I should try to not overtighten. But how does one know(?)

Use a nut driver, not a spanner and definitely not a power tool.
Screw in till it stops going down then 1/2 turn more.


#12

R

rigoletto

First, if you see fuel in the air horn when priming, there is no need to check the float level. Try this trick. Cut a stiff piece of paper or thin cardboard to a size that you can cover the carb throat with the air filter back still in place. Prime unit three times, place paper over carb throat, have someone start the engine. If the engine starts and continues to run when you remove the paper, I'm betting you have old fuel which is not volatile enough to burn at low RPM's.

OK. Doubt fuel is the problem, just a hunch. Primer bulb not sucking in vigorously remians the problem. But, as you say above, "air horn", isnt that snug against the carb machine surface when all attached?? How can one see fuel in air horn then? All I can see is drizzle/oozing fuel down square black plastic housing when pushing primer button. I have to push very fast, and about 25 times to get any drizzle. Primer is mostly sucking air, not any fuel, which one can "feel"/even hear as it sucks up fuel by venturi.

On your tip above on starting engine with paper covering carb throat, engine will no way start AT ALL without ether.


#13

R

rigoletto

Use a nut driver, not a spanner and definitely not a power tool.
Screw in till it stops going down then 1/2 turn more.

thanks. Thats normally how I do it.


#14

R

rigoletto

Went to HD to buy new bulb. Took apart carb AGAIN, reamed it with wire, carb cleaner, like usual. New gas. Filled tank. Drained bowl and measured about 1/2 oz of gas. Is that too low? No suction. Men, Im about to quit, but I cant. 1st carb that I have failed so far to get running.


#15

R

Rivets

If you feel that you cannot start the engine by manually chocking it with a piece of paper over the air horn opening, then you will have to open up the carb and find out why. You must remember that the priming system on this engine is just an air pump. When you push the bulb, you are forcing air pressure on top of the fuel in the float bowl. This should force fuel up the nozzle into the air horn. You are not pumping fuel, just pushing air which pushes on the fuel. It can only push the fuel so far, because of the small amount of air you are pushing. If this came into the shop, this is what I would do. I would clean and rebuild the carb using the following procedure.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

If my memory is still in tac, the new needle and seat part number should be 398188. You must be sure that the seat is seating at bottom of the inlet opening.


#16

R

rigoletto

If you feel that you cannot start the engine by manually chocking it with a piece of paper over the air horn opening, then you will have to open up the carb and find out why. You must remember that the priming system on this engine is just an air pump. When you push the bulb, you are forcing air pressure on top of the fuel in the float bowl. This should force fuel up the nozzle into the air horn. You are not pumping fuel, just pushing air which pushes on the fuel. It can only push the fuel so far, because of the small amount of air you are pushing. If this came into the shop, this is what I would do. I would clean and rebuild the carb using the following procedure.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

If my memory is still in tac, the new needle and seat part number should be 398188. You must be sure that the seat is seating at bottom of the inlet opening.

Big thanks, Rivets, for the details!! Good to know. I will remove carb again and compare against what you said.

But, update: ILENGINE posted above that problem could be the plastic housing doesnt seat flat against the paper gasket, allowing an air "leak". I noticed when I removed the housing and looked at the side of the gasket which is against the housing that the air "horn" ridge, which is normally visible as a crevice molded onto the gasket, has a section which does NOT show a crease. So, the gasket which should have somewhat of a crescent crease, has an interrupted molded crease, indicating it does NOT seat well when housing is pressed against the gasket and carb. This creates a leak, right? So, housing is warped (I searched and found out these plastic housings are JUNK!!

So, Where can I buy a new one online, people (that is, ifn yous think I should buy a new one)?

Thanks! I WILL NOT QUIT UNTIL I FIX THIS!!!!!!!!


#17

R

rigoletto

Finally figured out what 'air horn " means- it's the intake orfice on the carb, right? My goof- I thought it was the tiny narrow slit molded into the intake housing, where the air pushed from the bulb travels. Sheesh.......

Started it with ether again, mowed about 1/2 my yard, so carb works great in that regard. Stopped it, and pushed bulb- no priming. Gonna try the paper in front of the air horn tomorrow, when it's cooled down.


#18

B

bertsmobile1

You will find using a parts manual will be of great benefit.
mechanics use specify terms for bits & pieces .
As we need to buy these from time to time we tend to use the tems found in the parts manuals.


#19

R

rigoletto

First, if you see fuel in the air horn when priming, there is no need to check the float level. Try this trick. Cut a stiff piece of paper or thin cardboard to a size that you can cover the carb throat with the air filter back still in place. Prime unit three times, place paper over carb throat, have someone start the engine. If the engine starts and continues to run when you remove the paper, I'm betting you have old fuel which is not volatile enough to burn at low RPM's.

OK, Riv, I stuffed paper in front of carb intake, and it started!! So, does that mean I have bad gas? Why? Also, bulb still doesnt prime gas. So, even with bad gas, why does bulb still have trouble priming?

Thanks.


#20

R

rigoletto

You will find using a parts manual will be of great benefit.
mechanics use specify terms for bits & pieces .
As we need to buy these from time to time we tend to use the tems found in the parts manuals.

dont have manual. Tried to id the engine with codes stamped on it, but seems those coeds are useless. But thanks for the reply....


#21

B

bertsmobile1

done have manual. But thanks for the reply....

You can download them from Briggs & Stratton for free.
Very handy particularly for putting carbs back together.


#22

R

Rivets

With the results you posted, I suspect that the fuel level in the float bowl is too low. Follow the procedure I posted and I don't think you will need a manual.


#23

R

rigoletto

If you feel that you cannot start the engine by manually chocking it with a piece of paper over the air horn opening, then you will have to open up the carb and find out why. You must remember that the priming system on this engine is just an air pump. When you push the bulb, you are forcing air pressure on top of the fuel in the float bowl. This should force fuel up the nozzle into the air horn. You are not pumping fuel, just pushing air which pushes on the fuel. It can only push the fuel so far, because of the small amount of air you are pushing. If this came into the shop, this is what I would do. I would clean and rebuild the carb using the following procedure.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

If my memory is still in tac, the new needle and seat part number should be 398188. You must be sure that the seat is seating at bottom of the inlet opening.

OK, Riv, I did do most of what you suggested above including:

remove carb, flush out all orfices, soak for 24 hrs or so, in solvent, check float , and it had no fuel inside, so reused it. I did not do the new seat, but its passages are clear/free of obstruction. If you feel a new seat is my achiles heel, please let me know. All orfices are freed/clear. Re installed, and as I posted, engine starts easily with your paper in front of carb intake method.

So, what else would cause bowl to have below optimal level of fuel? Mower ran for 10 min or so, with no sputtering, etc. If I have to buy new carb, heck, I will. Im bedoozzled as to why float is too low (apparently) to allow bulb to prime.

Thnaks again, Riv (and other members)


#24

ILENGINE

ILENGINE

Some models of briggs engines have a rubber donut type carb needle seat. that seat will swell due to various things which will throw the float level off.


#25

R

Rivets

As IL said a swollen seat will throw off the float level. That is why in my procedure I recommend removing the old seat and installing a new one. Also, you didn't say whether you checked the float level. This must be done for this procedure to help you. If you don't set the float level properly you are just wasting your time and money.


#26

R

rigoletto

First, if you see fuel in the air horn when priming, there is no need to check the float level. Try this trick. Cut a stiff piece of paper or thin cardboard to a size that you can cover the carb throat with the air filter back still in place. Prime unit three times, place paper over carb throat, have someone start the engine. If the engine starts and continues to run when you remove the paper, I'm betting you have old fuel which is not volatile enough to burn at low RPM's.

OK, Gotta say, Im a bit confused. I did the above and engine started with paper in front of carb, but there was no fuel visible before pulling the cord. No way I have old gas. It is fresh.

Also, Another post above said if after taking apart the carb, held upside down, float should be level. I did this and man, I think we're finally getting somewhere, as the float is NOT level!! It is aiming "up", meaning, the hinge end is lower. Gotta be a bad swollen rubber seat, right Riv??

You are correct in suspecting/advising I should replace that rubber. Will buy one locally and try to pop it out with my compressor.......

Thanks.


#27

ILENGINE

ILENGINE

Carb cleaner has a bad habit of making that seat swell as well as other chemicals. it can also make is crumble is some cases


#28

R

rigoletto

Carb cleaner has a bad habit of making that seat swell as well as other chemicals. it can also make is crumble is some cases

thanks. good tip. will try to pop it out with compresed air. hope it works........


#29

R

rigoletto

thanks. good tip. will try to pop it out with compresed air. hope it works........

Sheesh, good thing it's not cutting season!

I popped out the seat, but al the shops nearby are out of business! So, figured Id order it online, but I dont know the exact carb # I have. But, I have these numbers, people:

On the plate above the muffler is : 125K02-0243-E1 (space) 03081157. I believe thats the model # for the Briggs engine. Should that be enough to identify the carburetor? Now, on the carb itself, are #'s: 6150, also 2183. also 8105, also 214122. So many #'s!

If someone here can let me know, I can order a kit.

Thanks


#30

ILENGINE

ILENGINE

You need repair kit part number 498260 if you want to replace the entire carb it is part number 799868


#31

R

rigoletto

You need repair kit part number 498260 if you want to replace the entire carb it is part number 799868

Big Thanks, Il!! Now, just for curiosity, How would someone like me find that out? I mean, no such # was on the carb........


#32

R

rigoletto

Now, this kit here:

Carburetor Rebuild Repair Kit for Briggs Stratton 492495 493762 498260 | eBay

is for 498260, but there are many parts in the photo which I cant figure out where they go. Should I be able to use ALL those parts?


#33

ILENGINE

ILENGINE

No you won't use all the parts. This kit fits some of the older engines that had adjustable idle jets, as well as the newer non adjustable carbs. I suspect you won't use the fuel adustment valves, or the cork looking air cleaner gasket.


#34

R

rigoletto

No you won't use all the parts. This kit fits some of the older engines that had adjustable idle jets, as well as the newer non adjustable carbs. I suspect you won't use the fuel adustment valves, or the cork looking air cleaner gasket.

Thanks. Good to know. Time to place order.


#35

R

rigoletto

Thanks. Good to know. Time to place order.

Well, finally got the kit and installed a new seat, and a couple of gaskets, along with o ring. Still no priming capability. I did check to see if the float was level when placed upside down, and it was, so that first got me excited. But, to no avail, as still bulb does not prime gas. Dang. Now what? Guess I could order a new filter housing(?). Nothing else to do, right, people?


#36

R

rigoletto

Sheesh, good thing it's not cutting season!

I popped out the seat, but al the shops nearby are out of business! So, figured Id order it online, but I dont know the exact carb # I have. But, I have these numbers, people:

On the plate above the muffler is : 125K02-0243-E1 (space) 03081157. I believe thats the model # for the Briggs engine. Should that be enough to identify the carburetor? Now, on the carb itself, are #'s: 6150, also 2183. also 8105, also 214122. So many #'s!

If someone here can let me know, I can order a kit.

Thanks

With the above engine codes, which part # should I order for the housing? Reply appreciated. Man, this project is taking forever.......


#37

ILENGINE

ILENGINE

There are two air cleaner bases that were used on that model of engine. fortunately both bases supercede to part number 795259


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