Replaced both head gaskets on a SV725-3027 and not engine will not start

[Thibs’ Tavern]

Like I said. I replaced both head gaskets which I have done numerous times on this engine. I put everything back together and it cranked right up like usual. It ran for about 30 seconds and then shut down. I installed two new spark plugs and verified that both of them are firing when it is turning over. I also know that I have gas all the way up to the carburetor. I took the carburetor apart and cleaned it up good. I thought maybe it got a piece of trash stuck in the jet. Put it back together and it’s still no starting. Does anyone have any idea what I can check now. Thanks

 

[Scrubcadet10]

first, i would check that the fuel solenoid (Anti-Afterfire solenoid) on the bottom of the carburetor is functioning properly... When you turn the key to the ON position you should hear a little click come from it. That is it retracting from the main jet to allow fuel into the jet.
Next i would see if it will fire on starting fluid or carb cleaner sprayed into the spark plug hole. a valve issue could be possible since the heads were removed, one or more may push rods could have hopped out of the rocker arms.
did you reset the valve clearance? appears to be between .004 and .006 for both

 

[Thibs’ Tavern]

I appreciate the reply but I figured out what it was. I did reset the clearance to .005. I left the valve covers off to visually inspect the valves while it was running. The problem was that on one of the valve covers has a tube that goes into the fuel pump. That tube provides the vacuum for the fuel to flow to the carburetor. I knew it had to be some kind of fuel problem because when I initially fired it up after the work was done it started right up. I also verified that both plugs were firing so I knew it had to be something with the fuel. Again thanks for the reply

 

[StarTech]

That will do it everytime.