90' DT25 tapping sound coming from motor

[southeast texas suzuki]

Bought a jon boat last year with a used 90 suzuki DT25 2 stroke motor. Ive had the boat out half dozen times since the purchase and overall it ran good, but never idled right so i suspected carbs needed to be cleaned. So i ordered all suzuki parts to do the job. Cleaned them real well and replaced all the fuel lines and strainer while I had it all apart. I decided since it was an old motor to replace the oil filter/ flow sensor just for peace of mind. Also got an original suzuki manual. Since i had the oil injection system apart, the manual says you need to bleed the air out of the system. I decided to wait on doing the bleed and just premix the gas for now to see if it would run. Started right up, ran great, idled great, and felt like it had more power. Spent 15 min running it then while under load i felt something "give" and the rpms when up kinda like how a boat acts when the prop comes out of the water. I throttled the engine back to idle and all of the sudden there is a tapping noise from the engine. It changes as the rpm changes. ? I was checking over the engine today and couldnt find anything visually wrong. Checked the 3 carbs for fuel which they all had, pulled plugs which looked fine, shined a flashlight into the cylinders and could not see any sign of damage on the pistons. Any ideas what that tapping sound could be? Its a 2 stroke so there really isnt a whole lot of internal parts. Will check compression once i pick up a tester , but for now im just looking for any advice. Appreciate any ideas. Thanks