Regular 87 octane should be sufficient
55 hp.
25 horse power.
motor will not run completely the correct way. motor my not be as strong any more
70 horse 1985 mercury outboard
It depends on what type of RV you have. Some motor homes will take diesel, while some others take regular unleaded fuel.
The 2000 model, Mercury 25 hp outboard, requires a minimum octane 89 rated, unleaded fuel, however, with the quality of gasoline being what is presently, it would not hurt to run the higher octane fuels.
Unleaded motor spirit
A 35 hp Mercury outboard, serial number OC144498, would be a 1990 tear model.
Unfortunately to find out the year of a Mercury boat motor one needs not only the serial number, but also the horse power rating. This allows it to be narrowed down to a specific year.
Its heavy man , I mean really heavy
Both the serial number, and the horse power rating are needed to determine the year model of a Mercury outboard.
RSX - "regular" unleaded with at least 85 octane, no ethanol. RSX type S - higher compression motor, requires 91 octane, no ethanol.