Picked up a used Murray with a Briggs. Started fine. Then I realized the gas tank was cracked. Purchased a new tank. Installed it today. Now my mower won't start. So far I've:
1. thoroughly cleaned the carb
2. New Oil added
3. replaced the gas tank
I did not replace the spark plug. As of three days ago, the mower turned over fine. Didn't think the plug needed to be replaced.
Since replacing the gas tank, today I tried to:
1. Spray starter fluid in the air filter intake - nothing....
2. Took off the spark plug, cleaned it, sprayed starter fluid in the engine - nothing....
3. Carefully removed the gas fuel line to make sure I'm getting gas in the line. Confirmed that gas is exiting the tank and in the line....
Notes:
1. The primer bulb doesn't seem to be extracting gas and displacing it in the bowl. No resistance felt when pushing the bulb. Feels like when I compress the bulb I'm just pushing air.
2. The fact that when I sprayed starter fluid in the engine upon removing the spark plug and don't even get so much as a cough, leads me to believe I've got a bad plug.
I'm wondering if I maybe didn't put the carb back together properly. I know I had issues with the main needle. The one that regulates the bowl - kind of looks like a pencil...
If I didn't install that properly, would that cause my mower from not starting?
I'm wondering if I maybe didn't put the carb back together properly. I know I had issues with the main needle. The one that regulates the bowl - kind of looks like a pencil...
If I didn't install that properly, would that cause my mower from not starting?
Dismantled the carb again - I reassembled it correctly the previous time. My carb is fine.
I looked at the magneto coil. there was a small blemish on the wire - where it meets the coil. So I replaced it with a spare magneto from a near identical MTD mower. The magneto is exactly the same - but not new. This coil looks much better, but I'm not 100% sure that it is functional.
Anyway, I installed the other magneto and still no spark. I followed instructions on a youtube video on how to replace the magneto, and I'm fairly certain I did it right. I used a business card to separate the magneto module from the flywheel magnets. I think I have the right amount of air gap.
I noticed too that when I engage the control handle, the cable doesn't move the kill switch much. Anyway, I tried starting the mower with the grounding wire attached, and I couldn't get it the mower to start. Then I removed the grounding wire and still no spark.
OK. So I got a spark. I think the problem was my gap. I got it to cough. it stalled. can't get it to start again. back to the drawing board.
#8
Vervepipes
* I googled the part number and it looks like a Briggs Quantum, so my troubleshooting is based on that.
If you removed the air filter housing and put it back on, the gasket between it and the carb may need replacing, accounting for the primer button not working. There are a few ways to check to see if the primer system works on these. With the air filter assembly off, push the primer button. On the back where it would meet the carb there is a channel in the plastic air filter housing, check to see that it is pushing air. On the carb, the filter housing's channel meets to a small air passage, try spraying carb cleaner with the extension tube in there to see if the passage is clear. Next, without screwing the filter housing back in place, firmly hold it in place while pumping the primer, experiment with slightly different holding pressures against the housing and slight position adjustments. If you can see gas shooting into the carb that way, then the primer system works and chances are the gasket is toast, releasing the primer's air charge to the atmosphere rather than the air passage.
I've had to do this to 3 mowers last week, one of which actually worked fine until I removed the filter housing to do some other work. Good luck!
Yea, I already replaced the air filter gasket. the bulb seems to work OK b/c when i press the bulb, I can feel the airflow. But I still can't get this mower to start. not sure if i somehow overlooked a jet in the carb?
thoroughly cleaned the carb one last time. Double checked the magneto. My gap is good. I've got spark - at least when the cover is off i can confirm spark by spinning the fly wheel and holding the spark plug against the engine block. Put everything back together, and pulled the cord, and got it to run. released the safety bar and shut the machine off. Can't get it to start again.
I'm out of ideas
#11
pugaltitude
You could really do with a spark tester to check for spark.
Has yours got a metal spark plug terminal?
They were prone for failing and allowing cold start but warmed up would cause no spark even after 30 seconds.
As long as carb is cleaned well, jet is cleaned in bowl nut, manifold is not cracked and fuel tank is good then i think your losing spark.
They are a brilliant engine and usually quite easy to repair.
#12
Fish
Put the mower up where you can see things properly, like a tailgate. Remove the air filter and cover and look into the carb throat
and push the primer bulb several times. You should be able to see a pulse of fuel squirt up into the carb throat, if you don't
remove the base, and lightly cost that base gasket lightly with a smear of sealant on bot sides, but not too much, and reassemble, keep at it until you see it prime, you may have to replace the base, as that plastic warps, and it needs to seal good
as that is where the pulse goes to the carb to push the fuel up to prime....
#13
pugaltitude
Noooooooooo dont put sealant on or anywhere near a carb.
Just fit more gaskets...
#14
Fish
Nooooo. It works for me!!!!!!! Just have to take it easy on the goo!!!!!
