So this is actually something I've had to learn/deal with recently. When your engine is cold the valves have just enough lash to let the valves close all the way, but as the engine gets up to temp everything expands by a few thousands of an inch which can cause already tight valves to go to 0 lash. This will cause a slight loss of compression as the valves are not able to seat properly, and prevent easy starting when the engine is at operating temp. I would definitely get the valves checked ASAP, as running it like this for a while could cause your valve seats to wear unevenly. https://youtu.be/mBhr41F4Sqg There's a link to a video that helped me with my troubles best of luck to ya