Starts, runs for a while, then dies. Then will not start right away.

[DAMatson]

Bertsmobile1,

I thought it best to continue the thread since I was actually having the same problem as the OP, and there did not seem to be a solution to this thread.

I apologize, but I already tried the cap test and it did not start to run better when the cap was removed, nor did I hear a sucking sound while loosening the cap, but suppose that aspect is arguable since the sound of the engine might have drowned -out that particular sound out.

-David

 

[bertsmobile1]

People panic, join the forum, find the problem then never bother to come back with a "problem solved" post

It is a process of elimination.
Grab a can of starter fluid and an inline red spark tester.
Fit the spark tester then go mow.
When the engine starts to die have a look at the tester.
If the tester continues to flash all the way to the bitter end and then flashes strongly when you are cranking the engine and it is not starting you have then eliminated the coil & spark plug lead.
\

The engine can stop for a few reasons .
Not enough fuel or too much fuel is one of them.

SO when it stops give the carb a SHORT shot of starter fluid.
If it fires right up then you have a fuel starvation problem.

If it does not start then you have an excess fuel situation

And of course do all of this with a nice new properly gapped spark plug.

If your engine has an oil level sensor, make sure that the oil is full to the top.\
Had a customer who perpetually runs the engine with low oil ( never checks it before he starts to mow ).
After about 10 minutes or so, a lot of the oil that was in the sump when he started is distributed all around the engine.
The oil level in the sump drope below the preset cut off ( appear to be a bit too high ) and the mower stops dead .
OTOH he pays me $ 30 to turn up, put about a pint of oil in the engine then he carries on mowing to repeat the same in about 2 to 3 months time.

Let us know what happens & we will walk you through what else is needed to be tested.

 

[DAMatson]

Continuing to see the problem after only about 30 seconds each time. Pouring more gas into the carb delays the eventual death of the engine.

I'm drawn to an observation by ILENGINE on a different thread about the solenoid on my carb possibly being defective and causing the plunger in the solenoid to close and shut off the fuel supply.

Know of a way to test that possibility? I can't see how to remove the solenoid, but if it is removable and replaceable, I would happily attempt that.

 

[ILENGINE]

Continuing to see the problem after only about 30 seconds each time. Pouring more gas into the carb delays the eventual death of the engine.

I'm drawn to an observation by ILENGINE on a different thread about the solenoid on my carb possibly being defective and causing the plunger in the solenoid to close and shut off the fuel supply.

Know of a way to test that possibility? I can't see how to remove the solenoid, but if it is removable and replaceable, I would happily attempt that.

The solenoid unscrews. If i remember correctly uses a 1/2 wrench. maybe have to be ground slightly thinner than normal to reach in and get on the two flat surfaces.

 

[DAMatson]

Yeah, it'll be tough for sure to get in there with a wrench, but before I started that angle of attack I've tried looking for a replacement solenoid, but came up empty handed.

 

[DAMatson]

Alright, I had been suspecting that the Fuel Solenoid as the problem, so I removed the bowl with the solenoid and replaced it with the old bowl with a straight screw-on plug. I used the NEW main fuel tube jet because it had a newer o-ring on it, and the bowl-to-carb gasket is brand new as well.

While it wouldn't start unless I primed the carb, the mower started, ran fine for more than a minute (a record for me, since it usually dies after 30 seconds), so now I'm certain the original problem was due to the Fuel Solenoid. I continued to let it sit running for about 4 or 5 minutes, while I cleaned up the mess of tools. I then decided to take advantage of the opportunity since it was mostly sunny out to actually get some mowing done.

Got about halfway across the yard when the engine started to sputter again, so I took the burden off the engine by coming to a stop, putting the gear in Neutral, and disengaging the blades. Immediately the engine perked right back up for about 10 seconds, after which it sputtered yet again and died. This was after continous good running for 7 minutes, the last two under load (in gear, and blades engaged). Now I'm really confused.

It cranks ok, but the engine still won't start-up when turning the key still, so I suspect there is still a clogged port in the original old bowl.

So I prime the carb and it starts and runs fine for a minute and thirty-seconds. This happens repeatedly.

Since the problem is now effectively worse, I took my old bowl off the new Carb again, then pulled the Fuel Solenoid off of my new Bowl and replaced it with the plain threaded plug from the old carb and re-installed the new Bowl back onto the new Carb. Still using the new Gasket and Fuel tube. Effectively, the entire NEW Carb is now installed back in, except that the Fuel Solenoid has been removed and replaced with a plain threaded plug.

It now starts right-up again without needing priming (so that would tend to indicate that my previous thought about the old bowl still having a plugged port is likely correct), but still dies after 1 minute to 2 minutes. So now I'm considering that when I replaced the bowl these last two times, maybe I mucked something up.

The first question I have is: the main fuel tube has a series of 3 micro holes (2 grouped together near the o-ring, and a 3rd hole about the middle of the tube) on two sides directly across from each other. Do those have to be aligned in a certain direction when placed in the carb bowl? I had thought that I had re-aligned them exactly how I found them on the NEW Bowl when I pulled it out originally, but maybe I got that alignment wrong.

Thoughts?

 

[cpurvis]

Check the vent on your gas cap. Under load the engine uses a lot more fuel. If fuel can't get to the carb, it sputters and dies. Also, fuel filter if it has one.

 

[DAMatson]

Thank you cpurvis!

The cap itself was confirmed as not being the cause a lot earlier when I pulled the cap off before the sputtering and eventual death of the engine.

However, your suggestion led me to investigate the fuel-line where I found a plastic curled burr in the gas-tank nozzle feed that the fuel line plugs into. The curl of this burr had hung-on to some gunk and was acting like a slinky with a movable dam that would uncoil far enough and allow some fuel through, but would apparently (at some point) coil back up and cut off the flow of gas. I can only presume that this burr originated from the milling of the fuel line plug on the gas tank.

I drained and removed the tank, and that's when I found and removed the coiled burr and the attached gunk. The hoses from the tank to the carb were all original, so I replaced them all as well, replaced the inline fuel filter, and now everything is working fine. I was even able to get in some mowing time before the mosquitos came out.

So the Fuel Solenoid definitely failed and was my primary/original problem. The plastic burr with gunk on it was a secondary issue that only served to create some additional head scratching. Thank you all for the contributions!

 

[cpurvis]

Good! Glad you got that resolved!

 

[bertsmobile1]

Good! Glad you got that resolved!

If popping some more fuel down the carb throat perks up the engine then you still have a fuel problem.
Remove the fuel line from the carb and crank the engine.
You should get a strong flow the full diameter of the fuel line if all is well.
I use a 2' length of fuel line on the pump held strait up in the air to access if the pump is working well enough.

Fuel pumps do occasionally go bad and can not supply enough fuel to feed the carb.
Crud also builds up in the fuel tank and blocks off the outlet.
I check for that by rigging up a temporary fuel tank.
Something about a quart is good if you want to give that a try.