mule backfiring stalling after warm up

[Ba64]

Helping a friend with his m274 it is in rough shape and was trying to get it running at least. Did everything I could about timing per all the references here. pulled the carb and put it through a berrymans chem dip. Did little else to the carb. Checked replaced fuel, checked proper flow and return. (To the best of my abilities)

Now in order of diagnosis, cranked no start,
replaced fuel, got it to sputter
cleaned plugs, worked better
cleaned carb, starting to run but would backfire stall
magnito serviced points cleaned set timing same warms up backfiring stalling

, now before I did the one tooth off, it backfired through the intake, after it now backfires through the exhaust.

Is the carb toast and dumping fuel? Are the points spring weak and fluttering? Im not into air cooled so its somewhat Greek to me. Last mule I worked on needed a fuel pump and after ran great.

Thanks for the help,

 

[Ba64]

Its still popping through intake, my mistake. Could it be a stuck valve? Any help is appreciated.

 

[MuleMac01]

Have You checked the rubber hoses on the air intake behind the carb under the engine data plate cover? sounds like you're sucking air.

 

[Ba64]

I have, sort of. Took that cover off to rr the carb and magnito, but I will do a better inspection of them, thanks
have had two opinions given to me that the carb is probably done. Going to check compression and if ok, order up a new carb.

 

[M813rc]

Check this hose, it is what MuleMac is referring to. Even small cracks can have a big effect on how the engine runs.

Even if it doesn't look cracked, it can't hurt to replace it anyway, they are cheap on ebay and from the Mule dealers.

Cheers

 

[The Auto Shop teacher]

The 3 things you need for combustion is spark (at the right time), fuel (in the right amount), and compression. If you have a nice fat spark, and the timing is correct, you might get a change of spark plugs. Since you only need two, it shouldn't break the bank. The next thing is to do a compression test while the plugs are out. You should have over a 100# or higher with a healthy engine. One problem that can cause popping is lifters that aren't pumping up, (usually caused by dirty oil clogging the oil intake). Changing the oil and filter adding about a quarter cup of Marvel Mystery oil sometimes will do the trick.

The last thing to check is to make sure the carb is getting plenty of clean fuel. Since our mules sit so much of the time and who knows how long they have sat before you got it. I would start at the gas tank, and drain it and 'carefully' shine a light inside to see how much corrosion and junk is in the tank. Change the fuel filter in the tank as well as the inline filter at the engine. Blow out the fuel lines both from the tank to the fuel pump, and make sure the fuel bleed tube (1/8" copper) line back to the tank isn't clogged. Then add fresh gas to the tank and try it out. Remember that this ethanol (gasohol with a new name), starts to break down after 6 months so make sure it is fresh. Good luck!

 

[Ba64]

Did a spark test before the magnito was serviced, it is getting spark. Fuel was drained and all the lines blown out. When I took the carb apart did my best to keep the gasket intact however it is leaking now. So I know the carb isnt doing the job correctly. Im thinking that the lifters are having difficulty so I picked up an oil change with some marvels the other day. Will probably fool around with it some more this weekend.

Another question since I didnt have a diagram for the carb. Im guessing the plastic valve and spring that fell out of the bowl is for the accelerator pump. And again educated guess that it goes back into the hole first with the spring on top. May attempt cutting a bowl gasket to see if I can at least get the performance I had before fooling with it.

Most of my attention improved things, with the carb spraying out the carb, it will fire and run for only a second or two.

The mule is very rough shape. Have yet to catalog the mechanical issues it has. Other than it will move when it was running.

Thanks

 

[Al Harvey]

I had issues with my Mule not wanting to run right. Wasn't backfiring, but I took it to an event and after it started to warm up it wouldn't run for more then 2min. Needless to say, that ended my parade day. I ended up ordering a carb for it and now it fires up on the second pull and runs strong.

 

[The Auto Shop teacher]

From what I am hearing from you, the fuel system is probably to blame. If you can disconnect the fuel line that screws into the carburetor, and hook up a fuel hose to catch the output of the fuel pump in a can, you can crank the engine to verify that the carburetor is getting a steady stream of gas. If everything is working you will see a squirt of fuel from the fuel pump about every second cranking. If fuel is working OK, replace the carburetor as you can get a new one for as little as $25.00 on eBay.

 

[Ba64]

I had issues with my Mule not wanting to run right. Wasn't backfiring, but I took it to an event and after it started to warm up it wouldn't run for more then 2min. Needless to say, that ended my parade day. I ended up ordering a carb for it and now it fires up on the second pull and runs strong.

This is exactly how it was before I started fooling with the carb. Thanks

 

[Al Harvey]

I'd also suggest putting a fuel pump on it while you have the carb off.

 

[Ba64]

[/BMule update

Pulled the carb off again and the bowl valve is getting clogged. Blew it out, made a new bowl gasket. It ran as well as possible for quite some time. Drove it off the property, put it in third gear and it took off. Unfortunately, clogged up and stalled again.

Tank needs to be rr'ed and cleaned.


BA64ARMORCARG-Private
*3*Wed Apr 13, 2016 3:12 pm


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[MuleMac01]

Well I guess you got your answer clean the tank replaces filters good luck!