Im working on a 2014 Toro XT6715-2070 149cc engine where its having issues on warm up. After starting it will run well for about 30 to 40 seconds or so then start to stumble for about 10 seconds, then runs OK for about 20 seconds, then goes back an forth doing this for about two and a half minutes then just starts to run well from then on. After its ran for about 6 minutes it still does not fully open the choke butterfly. The carb is a new OEM carb and I pulled the fuel filter to eliminate any possible issues with fuel restriction. The air filter is also new. Iv had this on other identical mowers and have not yet found a solution. The choke is one of these that mount directly the muffler and is the size of about a fifty cent piece that mounts flat on the muffler. It does not appear to be adjustable in any way. if I hold the choke rod open fully I do not experience this issue. Im sure Ill see this again so if anyone has any information for me that would be most helpful.

How old is this "suspect" battery? You stated the tractor is 6 years old but not how old the battery is. If this battery is also 6 years old you need not do any additional testing to it............6 years old is quite a bit longer than the norm for survival anyhow. The test data you collected also point at a worn out battery (drops to fractional reading of .45 VDC) if in fact that reading is accurate. That you read higher than 14 VDC when the engine is running proves that your charging circuits are working. The fairly rapid drop of battery standing voltage from 13+ VDC to 12.65 VDC in mere seconds is also an indicator that the battery is not performing at optimum. If you have a battery charger, disconnect the battery cables (or at least the negative cable) and charge the battery up. Then disconnect the charger and immediately read the battery voltage. Record your reading and continue to observe how quickly the voltage drops over a period of about 30 minutes time (but check the voltage every few seconds or so as you did before). If the voltage drops as quickly with the battery DISCONNECTED from the tractor wiring your battery is certainly worn out. If however, the battery voltage remains near 13.5 VDC or so for for a much longer time than when connected to the tractor wiring I would have to suspect a very high (and abnormal) amount of parasitic drain from something in the tractor wiring. Parasitic drain may be caused by a number of things and conditions, but we probably don't need to go further until we determine the actual health of this battery.

You're welcome. I was as perplexed as you with the "lack of" detail regarding how and when the fuel solenoid became energized. There is only one other circumstance I can liken YOUR situation to (engine acts like it wants to run when cranking, but dies when key is released from START position). Back in the '40s, '50s, and early '60s,, some automotive engine OEMs employed a "ballast resistor" in the ignition coil circuit. This "ballast resistor" was placed in the ignition coil circuit so that the normal system voltage, was cut by 50% before reaching the ignition coil. This meant that on a vehicle with a 12 volt electrical system, only 6 volts was fed to the ignition coil from the RUN position of the ignition switch. 6 volt systems cut the power to 3 volts. The most compelling reason for having to "rig up" the coil feed this way was due to the woefully inadequate batteries, switches, wiring and other things electrical, of that time. Mainly, it was the "weak" automotive batteries of the time that had to be "compensated for". Here's why: All applications that utilize a battery to power a cranking motor, will experience a dramatic "system voltage drop" throughout the entire electrical system during cranking. The "drop" is caused by the very heavy "current draw", or LOAD, of the starter. The voltage drop causes the ignition coil "sparkability" to diminish significantly. Add to that, a good frosty morning where the battery is cold and even weaker. Factor in further that the starter itself has worn brushes and sticky bushings and you will have so much current draw.....you might not even get a spark out of the coil. Enter the wizards of yesteryear (uhh, maybe they were just engineers). They developed a method to assure good sparks from the coil during cranking. The idea was to use a 6 volt rated ignition coil on a 12 volt system instead of the usual 12 volt rated coil (3 volt coil for 6 volt systems). But how can you do that? Wouldn't a 6 volt coil "burn up" if you powered it with 12 volts? Yes, it would........but not if you feed the normal RUN position power through a "ballast resistor" to reduce 12V to 6V before it reaches the coil. HUH? The "key" to how this arrangement assured dependable starting was in adding a SEPARATE circuit that would "BYPASS" the resistor while the starter was engaged. Bypassing the resistor meant that the ignition coil would be fed a "higher voltage" (in spite of system voltage drop) when cranking, than in normal running mode. After the engine "caught on", the starter was disengaged and the bypass circuit disabled. The current feeding the coil once again flowed through the ballast resistor and the 6 volt rated coil was safe from burning up. It was somewhat common in those days to confront a vehicle that acted similar to this Scag. (It wants to start while cranking, but dies when let go of key.) Most of the time, that particular problem would be due to a failed ballast resistor. But those systems had some other shortcomings. Sometimes you would find a vehicle where the owner would complain of "it just cranks and cranks and cranks, but if you turn the key loose, it might start up at that moment. THIS condition was due to the BYPASS circuit being open for some reason. OEMs accomplished "BYPASS" in different ways. Some added an extra post to the ignition switch that would power the bypass circuit during cranking. Other OEMs added an extra wire to the starter solenoid that powered the bypass circuit during cranking. When something became open in the bypass circuit, the coil would only be fed the reduced voltage. Then you were right back to the situation before the ballast resistor systems came into use. Advances in battery, ignition, starters, and conductors in general, made the use of ballast resistor systems disappear in the 1970s (except for some industrial applications). Oh yeah, magneto ignition systems were unaffected by voltage drop in the vehicle electrical system because they are "self contained spark generators".

Shusby: With all the work and replacement components go a few bucks further and do what I recommend numerous other do. 1st never use starting fluid via the carb venturi , if required only through the spark plug hole and only a short blast. Ether based starting fluids may dry and damage carb seals o-rings and gaskets and diaphrams within the carb. Use only carb cleaners for carburator starting spray use. Also drain out your old fuel by draining from the fuel line , do not tip over the mower to drain , you may drain crankcase oil into the breather housing and into the carb . Once drained add some carb cleaner & dry gas combination in case you have moisture within the fuel system. Let the new fuel and fuel treatment sit for about 30 minutes minimum. Then try the starting sequence via Carb cleaner sprayed within the carb venturi (throat) . Once started (may take a few tries) keep engine running until it will idle . This has been successful 90 % of the time . If not the carb jets will require removal and carb spray and compressed air may be needed to further remove dirt , debris within the carb circuits. Good Luck and let us know how you make out . I always try the KISS approach when gas starvation is indicated . Rather than throwing Time and $$$ at engine and component tear downs and Parts replacements that are not warranted.