Hey guys, first spring with my new to me ‘95 330DA. Over the winter I did some general tune up work such as plugs and impellers. Fired the engines up for the first time this spring and both engines idle smooth between 1-2k rpm but any higher the boat begins to shake. Any idea what this may be? I figured it isn’t a misfire since it idles ok and like I said this is in both engines. I should note that I ran it up to ~3k rpm after about 4-5mins of low idle. Are they just cold? Is it the exhaust blowing out from the exhaust billows?