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Mower: Snapper 7800190 (the Walmart special I think, it’s second hand)
Mfg. No: 7800190 SPV22675HW, 22" 6.75GT Variable Speed High Wheel Mower
This model has “Auto choke system
Engine: B&S 126T02-0675-B3

I bought this second hand years ago, no start. Cleaned the fuel system and carburetor. Ran for several years. I only use it to trim under some bushes on a berm where my rider can’t fit. I put it away last year (it ran fine) and didn’t need it till now.

Went to use it and no-start! Dang it. (yes fuel stabilized and put away dry)

1- Cleaned and re-gapped spark plug (it looked fine). Cleaned carb, fuel lines, new fuel, air filter and oil, still no start.

2- Replaced carburetor (cheaper than the rebuild kit I could find, jeesh what a waste)
Reassembled and it ran 1x but would not start second time. (New springs on air vane and governor).

3- Disassembled again and I found a cracked the manifold and had bad continuity on the coil
I repaired with the manifold with epoxy (a new manifold was NA or $40+), and bought and installed a new coil and spark plug.

4- The old vane did not have the clearance for the new coil, and I cut a small 1/4” section (minimal amount to fit) from the rib to allow for free movement and clearance. Thermostat arm moves freely and when it runs, it does operate.
Reassembled and it ran after a bunch of pulls and with me manually opening the choke (took off the vane spring) and pumping the throttle multiple times. After shut down, It will not reliably start.

• I have compression (didn’t actually measure it yet), I have spark, I suspect something with fuel and air. (I haven’t used ether yet)
• What is the proceeded to adjust the thermostat? Is a new air vane required or even going to fit?
• What am I missing, any other suggestions?

Thanks, John

Operators Manual & OEM B&S Engine Parts List above for your engine. Valve specs. page 9 in Operators Manual.

Check your valve clearances. They may have closed up over the years.

Also check everything in SB760.

SB760

@StarTech , thanks for the TSB, that helps... I'll tear into it agin the next couple days to test the air vane and thermostat clearances. Interesting call out for the cylinder shield, I'm guessing that's an air flow issue for the vane...

@mechanic mark , thanks for the links about the valve specs.

@ both of you, I was reluctant to dig in and pop the cylinder head, this confirms it, time to buckle up!
I was thinking a minimal compression number here is 90lbs and above with 100-110 being more likely, any sense on what spec should be?

I'll do some tinkering over the next couple days and report back, thanks again and all the best.

(any bets on a small chunk of the manifold plastic gumming up the works? smh)

You don't need to pull the head to check valve clearance that is done at the breather.

The camshaft has an ACR so compression numbers should between 70 and 90; not much more.

Finally had a chance to investigate, measured valve clearance of .004" on intake and a loose .080"/ tight .010" for exhaust.
Measured no compression so I pulled the head and found a bad head gasket. (man I swore I felt compression on pulling, I must have just been hopeful)

Found a typical gummy intake, will be cleaning and reassembling with fresh gaskets. What is the proper valve clearance on an L head like this?
thanks!
-jc

pictures to aid discussion:

reassembled and started on the first pull!
thank you @StarTech and @mechanic mark for helping me think through this.

At the end of the day it turned out to be multiple issues and the worst part was the compression issue (bad head gasket) that came on slowly.