I have 540 twin engines and the port engine will not go above 3500 rpms. Engine is down 300-400 rpms at idle compared to starboard side. these are the steps that have been taken so far to try to resolve this problem:
1) Compression test. All cylinders are at same compression. No variation.
2) MSD box changed- Same results
3) Plugs and Plug wires changed- Same results
4) Inginition module changed- same results
5) Fuel pump changed-Same results
6) Carb checked and rebuilt-Same result
7) Fuel lines checked to make sure a full line of gas was getting through-same results.
Engine starts and sounds great, but will not make it past 3500 rpm's. Also at 2000rpm's the port engine begins to loose power and throttles must be seperated to keep engine rpm's equal to the starboard engine. HELP! any advise would be greatly appreciated.