If you are using an older Snap on impact, they are some of the weakest impact guns ever made. Buy or borrow a newer impact of almost any brand, use a shallow well impact socket and it will come out. The newer impacts have enough power to snap that bolt in short order

The heavy bulky socket does make sense. Eliminating any flex and shocking it more. I tried the starter method last week about 5-6 attempts. Even thought about putting the charger on crank in addition to a good battery. The impact I have is the 8850 and also have 6850 with new batteries as of recent. They’ve both worked great for all my other needs.

I borrowed a local semi/tractor repair shops 110 impact. I did try penetrating oil and brake fluid but it’s highly likely not getting much past the bolt and washer up against the harmonic balancer. I may have to continue that with the heat cycles as mentioned. Also the 3/4” breaker to help eliminate flex. The bolt head is a 12 pt 5/8. The engine was assembled over a decade ago by guy who worked for Valako.

now that he told us what bolt is stuck.the starter trick works on many engines.

A decade is not a long time for an engine bolt, Assuming its corroded and not mechanically damaged, I would try heating the bolt head to the point of dull red, then squirting water onto the bolt head (and not reuse the bolt). The heat will radiate into the crank expanding the size of the hole, the shock of cooling will reduce the bolt without cooling the crank. If its corrosion it should spin out easy, if its over torqued or, as stated before damaged threads, its going to take brute force. Air impact will have more force than electric.

Look at the mass difference. And it works. Wonder if they make one for your size bolt ?

Again, difference made is for impact guns. Impact action much greater with a heavier socket. Won’t change much if used with wrench/bar lolol

👍. Going to attempt this afternoon. I’m thinking a transmission funnel for the cold water. Whatever I use I’ll be sure and isolate to the bolt head as much as possible.

Wait, wait, wait, you been doing all this and didnt round the head off yet? Broken flat panel TV's, thrown the wrench thru the wall and threw a beer bottle across the shop?

I clearly dont have the same ability or LUCK as you! Bwahahaha.

You need an air impact gun sir. The balancer itself will absorb the hammering from a battery impact gun. A good air impact will take that bolt out in seconds.

Have you tried to give it ugga-duggas both ways, tighten, and loosen? Just enough to break tension.

I've also had luck with a REALLY long pipe on a breaker bar, and literally hanging from the pipe for a few moments. Do you have a way to keep crank from rotating for such?