How fast should my boat go?

-I have an 18ft sting ray with a 4 cylinder motor and it seems like it is going slower than it should. What speed should it be at?so very many variables......



weight, condition/cleaniness of hull, type of hull, prop type/size/condition, motors condition, even wind and water roughness play a part.



i'd say roughly 35 tops. but 25 might be closer to correct depending on EVERYTHING....

i'd also say dont trust the traditional speedo. a more accurate fishfinder and its speed pickup or gps (portable one for a car works).



i say both of those because my 16' alum flat bottom goes about 40, maybe 45, with a 60 hp merc turning a black max series 14" pitch prop, and the new speedo reads low when compared to either gps or fishfinder.
not sure of the actual engine specs,but it should turn up about 4800 rpm at wot.spec should be on the flame arrestor cover, along with other data.your top speed should be in the high 30s,maybe low 40s depending on the condition of the prop and how the boat is loaded.++++++++++++++++edit+ sorry about the answer.with no other info i assumed it was an i/o.
I have no Idea on the actual speed, that differs between each boat, and engine.



Clean up your engine and check for any Propellor damage.



If both these are okay - bring it in to be serviced. As long as it seems to be going slower to you.
100
16.5 mph... tops