2008 S6 Express Need New engine

[SOUTHVIEW]

I have a used 2008 ST with the kawasaki motor. 1 1/2 years ago it wouldn't start one morning only pop and backfire. I adjusted the valves and no change.It had never given us any trouble before. Anyways I was about to move and sent it to a local shop who said it needed the valves redone. Had them do the repairs and return. Cart would start great cold but once you stopped it would not start easy. Would pop and backfire then start. Called mechanic he picked up and said he adjusted carb and valves again and everything was good. Returned again same problem. Anyways after going round and round I come to the conclusion the valve job was not done correct. Paid $300 for the first job. Cat has roughly 300hrs on motor. Runs good except when it comes to take off again. Have replaced fuel pump with another and then replaced carb after taking apart and seeing the plastic float was worn. Still same thing. Wife refuses to drive cart since all this has happened.Doesn't trust it. I have found a new OE motor on ebay for $1000. Do i just put a whole new motor in it or redo,replace the head and valves? At this moment I am thinking new engine route. I have customized this cart and we still would enjoy it. I would still have to do something before I could sell it anyway(**** conscience). Wife says try to trade it in and go electric! Opinions and advice please.

[SOUTHVIEW]

sorry meant to put 200hrs on motor. Did a compression check and have 150psi. I think I found the problem.It takes a couple of seconds for pulse line to the the fuel pump to build pressure. I took a wire and pushed it down the rubber line and now the pressure is building faster and the fuel filter is stying fuller. I had already ordered a new motor and am still going to put it in to make the boss happy. Even though, I am pretty sure it is fixed. Anybody interested in a used motor?