18 hp Briggs V twin problems

[Daniel H]

ok heres the deal.. one of my skids dropped a valve last week , got it fixed.. it sat for about 3 days took out on a job and it runs fine until I pull the trigger on the gun, then it boggs way down I have cleaned the carb, it is getting plenty of fuel, Thinking it might have something to do with the unloader it opened it all the way up.. my brain aint working right now, any ideals?

 

[IndyExterior]

The big question is why did it drop a valve. Broken retainer, spring etc. I'd be worried it got into a piston and cracked it. Compression test should help. I think the chances of dropping a valve and having an unloader problem at the same time are unlikely.