Yeah that's exactly what it's doing. Won't get past 3000 rpms. Gonna try to change the plugs first. But I'm thinking carb rebuild is gonna be the fix for it
You're probably going to want to check all the possible causes.
Several years ago, when I had the OMG 460 engine in my Four Winns (Sig below) , I had a problem with not making it to max RPM (5000) Best I got was 4000RPM.
I bought the boat from my brother who had replaced the plugs, points condenser and plug wiring. He told me that he did not check the timing and I suspected it to be the problem.
After checking compression (150+ all cyls) Timing slightly off but re-timing only gave me about 200 RPM (to 4200)
I even rebuilt the carburetor which had never been apart since 1987. Only thing wrong with the carburetor was the destroyed gaskets (I destroyed taking it apart)
I tried everything. The compression check was last and I had the valve covers off while checking the compression so I could see the rockers moving as I turned the engine doing the check
That's when I noticed that I had about 3 or 4 rockers on on each side that barely moved at all when turning the engine.
The camshaft had several flat (intake) lobes on it and the those intake valves were barely opening at all!
I was shocked. I have never seen a low time engine that had a flat cam. I suspect it was either never broken in correctly or it was the Slick-50 he used in the engine!!
Anyway, That list is pretty extensive, but a flat cam is not one of the listed problems!
