The entire Briggs theory is apathy, same as a Craftsman Tractor. The thinking is that most people don't pay much for Briggs powered equipment, so it doesn't see any maintenance, and for the most part is abused; e.g. left outside all winter, no storage, fuel contamination and so on and it is really a shame to see what shops are quoting for repairs when they can get to them in September! Two cases in point just today: Two Craftsman tractors, a 1000 and a 2000 series. The 2000 I started in on first, a two-year old machine which would only run with the choke on last fall was subjected to outdoor storage, on Cape Cod with the crazy wind and driving rain all Winter. Long story short, with a crankcase full of water, the #2 connecting rod in the 20 HP Briggs I/C Plus broke. What a shame. It now has a 14 hp Kohler Command sitting between the frame rails, thanks to Craigs list. The 1000 is not so fortunate. The 14.5 hp Briggs Intek had no air air filer housing on it, and is packed full of water. No worries, I/m not an Intek fan anyway. Thanks again to eBay motors, a local pickup on a Vanguard twin was made and once again these nice machines will mow acreage. Flip these machines over and they are pretty much the same underneath. Sure some have a cast front axle and electric PTO's however they share the same powerplants and transaxles. My personal mower? A Deere (later model ) 317 with a Kohler and a hydro rear mounted tiller. Have a great one!

In looking at the wiring diagrams for both the machines (917.276020 & 917.276310), I see no differences between the two except for the Kohler version (020) featuring an operator presence relay where the Briggs version (310) features a more "complex" seat switch to accomplish the same goal. If,........you are connecting the white wire to the small terminal on the starter solenoid, you are making the correct connection,........AND the solenoid is in fact mounted to a grounded, metal surface or has been provided with a separate grounding jumper wire to ground the solenoid case! So, you might want to test that the solenoid is grounded by touching the probe of a test light (or volt meter) to the battery positive post and the other end/lead to the metal case of the solenoid body. If you detect voltage or the light burns, the solenoid is grounded. If you don't detect voltage, it is not grounded and you need to address that first. So let's go through some checks to determine what the trouble might be. The following outline is a step by step that will guide you through. Refer to the wiring diagram for your 917.276020 for the identifying "alpha characters" I refer to in the text. Make certain there is not a blown fuse before you do these tests. (begin test outline) It could be a "bad key switch" but my feeling is "bad clutch/brake switch", but it could be a "bad PTO switch" just as easy, so let's do some testing first. You have a volt meter and/or 12V test light? Be advised that moving or wiggling wires while doing these tests could result in continuity being accidently restored AND this might cause the starter to engage when you don't expect it to. To guard against this, unplug the small white wire from the starter solenoid and cover the wire terminal with tape to prevent a short. First off, you will need to access the backside of the key switch. Step 1. Find the WHITE wire on the back of key switch connector. (leave the connector attached to the switch) While holding the key in the start position, probe the area where the white wire enters the connector body with a test light or a volt meter. You should detect voltage on the test light or the volt meter. If you do not detect voltage, replace the key switch. If you detect voltage, go to step 2. Step 2. Find the PTO switch and identify terminals C & G on the switch. Probe terminal C while the key is in start position. If you detect voltage at C, probe terminal G next. If you detect voltage at C but not at G, replace the PTO switch (make double dang sure the PTO switch is in the OFF position). If you detect voltage at C & G, go to step 3. Step 3. Locate the clutch/brake interlock switch (should be near the pedal or close by, must be attached so pedal linkage can operate the switch. This switch will feature 4 wires, 2 will be white. With the key in the start position, and the pedal locked or held down, probe the white wires of the brake/clutch switch. If you detect voltage on one white wire only, make certain that the switch plunger is actually moving in far enough to operate the switch. If the plunger is moving far enough to operate the switch, but you still detect voltage on just 1 white wire of the switch, replace the clutch/brake switch. The seat switch does not inhibit cranking on this mower, it only functions to kill the ignition spark. Malfunctions in the PTO switch or the clutch/brake switch are capable of killing spark AND inhibiting the starter. Remember to reconnect the white wire to the starter solenoid after testing. I hope this helps in troubleshooting the interlock circuits. (end outline) After doing these tests, post back your results.

OK- Sounds like the carb is too full. The needle/seat is likely leaking, allowing too much gas in the engine. I would have thought it would either clear up at high speed or flood the engine at low. I'd suggest downloading the IPL from the Briggs site for your specific engine, which you might also post the Model & TYPE for our information. There's a good chance a piece of "crud" is preventing the needle from sealing off the gas flow from the tank. Knowing which specific Briggs would be useful. In a nutshell, you have to remove the carb bowl, float & needle and flush the fuel line for a couple seconds.

I am by no means an expert but this sounds exactly like an issue I had with my 1987 Sears GT-18 with a twin Briggs. The tractor started smoking immensley on startup (white smoke) and then would die. Through some troubleshooting, I found that the crankcase was full of gasoline. I drained it and filled with new oil. I then did some research on the internet and found someone with a similar problem. A fella had suggested to him to check the gas cap for blockage. So, I removed the gas cap off my fuel tank and started her up. It started and smoked a lot (residue oil in the cylinders) but soon ran smooth and clean. Turns out my gas cap was clogged and that was apparently causing the vacum from the engine to draw gasoline into the crankcase from the carb. I got a new vented gas cap and have not had this problem again. The tractor has run great all summer. I may be off the mark, but it may just help this issue.