bertsmobile1
Lawn Royalty
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- Nov 29, 2014
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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.
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Engine wont prime gas
- Thread starter rigoletto
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Export threadUse a nut driver, not a spanner and definitely not a power tool.
Screw in till it stops going down then 1/2 turn more.
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.
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.
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.
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.
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.
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!!!!!!!!
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.
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.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 64
- Messages
- 24,742
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.
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.
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.
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....
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