Ford 172 sputter

[tulsa zoo]

I am having a persistent problem with these 172 engines. at idle they give occasional sputters. Is this just normal for the 172? Or what is causing this? I have rebuilt the distributor, new coil, new resistor, new plugs, I feel the carb is set properly. these are in our trains so get long hours of use.. quite a bit at idle and often not much at high throttle.

 

[Tall T]

I didn't hear you say, "new plug wires".

My last case of the occasional cough of the 134 was cured with a new solid core plug wire set I made up.

 

[tulsa zoo]

yes ! both have recently had new wires put on.

 

[GB in MT.]

[b:f95e751622][i:f95e751622]
T....Z;
You say .....: these are in our trains so get long hours of use.. quite a bit at idle and often not much at high throttle.

I'm thinking....Engine heat, making condensation in the fuel tank.
Also, if the humidity is high, and train not moving...?????, then fuel is letting condensation/water, settle to bottom of the tank.

Especially hard to have BOTH engines, with the SAME problem???

I would check both fuel tanks, for water setting in the bottom !!!!! ALSO, check the 'BULK' fuel tank that is used to fuel out of, for the trains.

Might just be a 'pipe dream', but don't take too much to check it out!!!

Gary
[/i:f95e751622][/b:f95e751622]

 

[tulsa zoo]

thanx I will check that. mabe even add fuel dryer somehow or a drain like in aircraft to check low point for water.
ill look into our bulk tank also...see what I can do there.

I have one running quite well but this other has always acted like this. and been worse this last week or so.

 

[Indiana Ken]

One thing that is critical to a steady idle is the fit of the throttle shaft within the carburetor body. Wear of the shaft or carb body results in a sloppy fit allowing for air leakage and can allow the butterfly valve to change position. Also, check the condition of the lever attachment to the throttle shaft - looseness here can also allow for a changing position of the throttle shaft/butterfly valve. When the engine sputters the load changes and things reset.

I had both conditions on my 16 HP Kohler in the lawn tractor. I corrected the looseness of the lever to throttle shaft attachment with signifcant improvement in idle quality. I still have wear in the carb body and sloppy fit of throttle to address when the grass stops growing.

Good luck

 

[lha]

My Grandfather had a tank for gas on his farm,and had a glass bowl filter inline underneath where the gas came out[gravity
flow],and never had problems with gas. He checked for water daily and would clean the filter when needed. Of course,the old
tractor had the same style filter as our Ns do. Most of the work on the farm was done by horse and mule[he said that the tractor
demanded gas,didn't cost anything to feed the horses]. He had an old Allis Chalmers.

 

[souNdguy]

Skip the fuel separated. It will be near useless with ethanol gas...

 

[tulsa zoo]

we use 100% gas