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Simplicity 725 Update


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#1 1978murray OFFLINE  

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Posted June 04, 2013 - 07:52 AM

well I got the new head for the simplicity yesterday. so I put my carb from my panzer on it, and gave it a run.  it runs, but not good.  it only idles, if u give it any throttle it just dies. and when its idling there it likes to stall for no reason.  Ik my carb is set up perfect and all.  But anyway if it does stall it will not start back up again. idk wats wrong any ideas



#2 boyscout862 OFFLINE  

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Posted June 04, 2013 - 08:11 AM

Make sure that there is plenty of clean gas getting to the carb. Check the spark when it dies. Good Luck, Rick

#3 1978murray OFFLINE  

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Posted June 04, 2013 - 08:26 AM

Make sure that there is plenty of clean gas getting to the carb. Check the spark when it dies. Good Luck, Rick

it has brand new gas I bought 2 days ago. and after it dies it still got perfect spark.



#4 boyscout862 OFFLINE  

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Posted June 04, 2013 - 08:45 AM

But, is the gas getting to the carb. There can be a blockage in a line or filter. I've seen a blocked gas tank vent cause your problem. Is it overheating? Some times a hot engine can cause vaporlock. Come to think of it that gas tank may have a filter on the valve at the bottom(both of mine do) that could be partly plugged. These intermittent problems can be real difficult to solve. Good Luck, Rick

#5 1978murray OFFLINE  

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Posted June 04, 2013 - 09:51 AM

But, is the gas getting to the carb. There can be a blockage in a line or filter. I've seen a blocked gas tank vent cause your problem. Is it overheating? Some times a hot engine can cause vaporlock. Come to think of it that gas tank may have a filter on the valve at the bottom(both of mine do) that could be partly plugged. These intermittent problems can be real difficult to solve. Good Luck, Rick

right now it has a plastic tank on it from a newer tractors rigged on it. gas is getting to the carb fine. and it seems like its running better this morning.  except for the governor issue im having


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#6 boyscout862 OFFLINE  

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Posted June 05, 2013 - 09:14 AM

We have the old B&S Shop Manual for downloading. Go through the governor adjustment proceedure. Sometimes its the thin rod from the governor to the carb has gotten bent. I still haven't gotten my Big Ten running yet. No time to work on it. Good Luck, Rick

#7 JakeC OFFLINE  

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Posted June 09, 2013 - 09:13 AM

I have had this issue with my allis b10.

Whats happening is the fuel bowl is draining and the feed to it is too slow to keep up with off idle. I can tell this because the tractor wont start again after a stall. This is because of a restriction in the fuel line to the carburetor. From what i have found out, the choke on these updraft carburetors will put a small vacuum on the gas tank until the fuel bowl is filled where the needle valve shuts off any more flow, if this is incorrect someone feel free to correct. If you don't have an air filter installed supplying a little back pressure then the fuel bowl in the carburetor will have trouble filling.

Other possibilities is that the float bowl is set too low. When flipped inverted and disassembled the float bowl should be close to level.

Here is a way to get the fuel bowl filled.

DO NOT TRY IF YOU DON'T FULLY UNDERSTAND

To fill the fuel bowl open gas cap, clean off gas cap area, blow a tiny amount of pressure into the gas tank. Like no more than what you can with your lungs. (I us my lungs to do this, breathe air away from gas tank, blow til a little pressure is made, you can hear the fuel entering the fuel bowl. close lips and move head away from gas tank and turn head to side. This makes sure no fumes affect you. If you don't 100 percent understand what I'm saying then don't do this.) When a very very small amount of pressure is applied you will hear the fuel entering the fuel bowl. If you have fuel leaks from this let me know in a reply.

So in summary.

Fuel is running out in the fuel bowl and the fuel line cant supply enough gasoline to keep up with off idle rpm.

Possible issues

Fuel filter (if installed) is mostly clogged.

Carburetor float bowl is not allowing enough fuel in the carburetor bowl.

Fuel line Is slightly clogged.

Shut off valve on the gas tank is bad (if its original it has a 90 deg bend and a shutoff portion, it will also have a strainer on the installed into tank side, this can easily clog. If its original replace it with a new one or just a 1/8 npt to 1/4 barb 45 deg if you can find it.

Idle mixing screw is all of the way I AND the jet is not seated all of the way. You would know this because there would be fuel leaking out of the carburetor when it sits still. Let me know if there is fuel leaking out also as this is another problem. It actually can leak from 2 locations and they both mean something different. One is the fuel bowl is over filled, the other is the jet that is under the idle mixture screw is not seated or is leaking around its bottomed out seat.




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