Mower Help

[ribber]

Father in law gave me an older Murray riding mower. It fired right up and I drove it home (he lives down the street). The next day, I went to crank it up and it wouldn't start. He has never had any issues with it starting. He used it sparingly, but it is about 15 years old.

I drained fuel and added fresh.
Verified fuel flow to carb by removing hose (filter not stopped up)
Verified spark (visual), but bought a new spark plug anyway.
Verified seat safety switch (no spark when not engaged)

It still won't start.

Don't like to do it, but as a last resort removed breather and sprayed starting fluid in carb. It still won't start. Not even attempt to fire off? I've never seen one that wouldn't at least try to start with starting fluid, so I'm puzzled.

When cranking with starting fluid, flames backfire from the carb. Also, occasionally the positive cable terminal will spark when I first turn the key.

Does anyone have any advice? I keep thinking it's something simple I'm overlooking because it ran great the day before. I was leaning towards the carb needing to be cleaned, but thought it would at least fire off with starting fluid?

 

[ribber]

Edit:
The positive cable terminal on the starter is what will spark occasionally.

 

[Cmp1]

Is it the terminal or cable? Is the starter cranking?

 

[ribber]

Is it the terminal or cable? Is the starter cranking?

Appears to be the terminal but I've only seen it spark a few times. Yes the starter is cranking the engine.
I've got spark with the plug out of the head and apparently inside cylinder too because it's backfiring through carb.

Think I'll take carb off and disassemble although I don't think it's gummed up. I guess it's possible there's a blockage in there. The breather/air filter was very dirty.

 

[SwampMoss]

What about the Flywheel Key?

 

[GeorgiaBob]

A few years ago I had a problem with a John Deer that took me almost an hour to figure out It was just a few weeks after I got the riding mower. Turns out that the fool trying to start the mower didn't have the break pedal depressed. When I put my foot down on the break that disengaged the starter cutoff and it started first crank.

I am not saying that you have overlooked something as simple and obvious as I did - but????

 

[ribber]

What about the Flywheel Key?

I thought about that. I'll check, it may have sheared.

 

[ribber]

A few years ago I had a problem with a John Deer that took me almost an hour to figure out It was just a few weeks after I got the riding mower. Turns out that the fool trying to start the mower didn't have the break pedal depressed. When I put my foot down on the break that disengaged the starter cutoff and it started first crank.

I am not saying that you have overlooked something as simple and obvious as I did - but????

I always think it's something simple like the brake pedal or the seat switch but that's not it. The starter won't even engage without the pedal depressed, I tried that.

 

[GoldDot40]

There's about 3 different safety switches. One at the clutch, one at the gear selector and one under the seat. I'd test each one for continuity with a multimeter.

 

[JackSprat]

There's about 3 different safety switches. One at the clutch, one at the gear selector and one under the seat. I'd test each one for continuity with a multimeter.

And if it has a blade engagement check that. Won't crank with blade engaged.

 

[JackSprat]

BTW just a test, clean the old plug and put it back in.

 

[Cmp1]

If your having a spark at the starter,,,, probably be the cable, replace the cable, big load on the battery,,,,high resistance,,,,

 

[1gr8bldr]

Sounds like a safety switch. My seat switch would go out so often that I eventually bypassed it. The electrical spark is a loose wire. Not hitting with starter fluid is proof of a safety switch keeping it from firing.

 

[livetohunt]

If it is not something simple being overlooked it could be ethanol fuel that was in it. You mentioned it wasn't used much. Was the old gas in it for a long time? Maybe clean the carb.

 

[ribber]

I'm done with it for now before I get mad and beat it with a hammer lol.
Still won't start.

New plug that has a nice strong, bright spark
Cleaned carb (it was not dirty but removed and cleaned anyway)
Key not sheared
Cleaned and retightened starter terminal (nut was loose)
Spun motor with plug out and finger in hole and it does have some compression.
Spark plug won't spark without seat switch depressed so its working
Motor wont spin without brake depressed or blade engaged so those 2 safety features are working.

Don't know what else to check. It has fire and fuel. And it won't even attempt to start with starting fluid or WD-40, which really puzzles me. But it's igniting because flames will shoot back through carb. Maybe it has a stuck valve?

 

[SwampMoss]

What about checking the Valves to make sure they are adjusted correctly?

 

[ribber]

Finally figured it out.
Pulled the side valve cover off and saw that there is a ring around the intake valve keeping it from closing. Don't know if the ring is from the seat or the valve head itself.
This would explain why flames were blowing back through the carb, and why I couldn't get a compression reading.
Now to the next step.