PWK 28 was running rich and now won't run

[408mini]

im running a predator 212 with a billet rod, flat top piston, new spark plug, 10krpm flywheel, and an amazon special pwk 28.

just got it on after installing a #115 main and #38 pilot it was running really rich but running and i took it for a test ride and it ran "fine"
Came back to it the next day to get it properly tuned and it started, ran for a little bit and completely died and wont start up again

I originally thought the spark plug was fouled and it wasn't however it was completely black so i cleaned it off and it has good spark

fuel is getting to it, cleaned out the jets since I thought the gas could've clogged it up

any tips?

 

[ole4]

Picture of the plug. If it is black good chance it's your problem. You either need to clean it with abrasive blast or heat. It may spark outside the motor but under compression voltage requirements are higher.

 

[408mini]

Picture of the plug. If it is black good chance it's your problem. You either need to clean it with abrasive blast or heat. It may spark outside the motor but under compression voltage requirements are higher.

ill try that out and let you know

 

[Minimichael]

Open header? What main jet came with the carb? You may want to go back to that for a starting point. Since you're running rich.

 

[408mini]

Open header? What main jet came with the carb? You may want to go back to that for a starting point. Since you're running rich.

I’m running an open header, and not sure what jet came original but I’m pretty sure it was a #110

I just replaced the plug and it still doesn’t want to turn over. Carb is also backfiring on occasion

picture of old “cleaned” spark plug:

 

[Minimichael]

Backfiring out the carb... Has your timing slipped?

 

[408mini]

Backfiring out the carb... Has your timing slipped?

ill see if it has, it has problems with timing earlier but i fixed it with a new key and flywheel (or so i thought)

 

[408mini]

Backfiring out the carb... Has your timing slipped?

Yep, just took the flywheel off and the advanced timing key I got snapped in two

Crank is shot so I ordered a new one. I’ll give an update when I reinstall it

 

[Thepaetsguy]

Yep, just took the flywheel off and the advanced timing key I got snapped in two

Crank is shot so I ordered a new one. I’ll give an update when I reinstall it

In the flathead world the flywheel is tightened with no key at all on purpose. did you lap the flywheel to the crank?

 

[Minimichael]

Shame the crank is damaged. That's why we use aluminum keys.

 

[408mini]

In the flathead world the flywheel is tightened with no key at all on purpose. did you lap the flywheel to the crank?

yeah i lapped it properly, it was the aftermarket key i got that failed, it was one of those offset keys instead of a shaved key so it snapped at the thinner joining point

 

[sparkwizard]

If the nut was torqued properly, the flywheel should not have moved, whether there was a key installed or not.

 

[Thepaetsguy]

If the nut was torqued properly, the flywheel should not have moved, whether there was a key installed or not.

Do 212cc’s have a spring/bow washer under the starter cup? Briggs do and if that washer is left out the very small portion of the starter clutch that contacts the flywheel is not enough and the key will shear.

 

[JimN]

Do 212cc’s have a spring/bow washer under the starter cup? Briggs do and if that washer is left out the very small portion of the starter clutch that contacts the flywheel is not enough and the key will shear.

No.