There may be some kind of debris in the air fins - maybe the governors are stuck and it is reving too high and overheating. Or it may be low in oil.
The maximum speed of the 1961 Fiat 1100 4cyl 55hp is 75 MPH.
The maximum speed of a 1962 Renault gordini 1093 4cyl 55HP was 65mph or 104.60kph.
The maximum speed of a Peugeot 204 wagon 4cyl 55HP 1972 is 81 miles per hour.
50:1
90mph
The 805cc v-twin Suzuki has 52-55hp.
This is a 2 cycle engine.
845 cc / 51.6 cu in
73 mph.
Mine is 100:1, however best ring the dealership to make sure,
The Yamaha 55hp outboard typically features a compression ratio of approximately 8.5:1. This ratio can vary slightly depending on the specific model and year of the engine. It's important to refer to the owner's manual or the manufacturer's specifications for the exact compression details for a particular model. Proper compression is crucial for optimal engine performance and efficiency.
50:1 is usual, 32:1 is also OK according to some.