please help

[55captain]

i bought a 70 hp.evinrude it has a decal fast one on it im trying to find out witch year it is so i can find the specs on it the model#is e70elcsa...... the searing #is g7o89103 i have a 15pich prop.pushing my boat at 30m.p.h runs good is this an adiquit pitch.or would a smaller pitch give me more speed.also once in a wile it lets out a backfire when starting is this a concern....my boat is a 16 foot tri-hall open bow does 30 mph seem like the proper speed of the engine with my boat....thank you for you help everyone

 

[ezeke]

Re: please help

e70elcsa is a 1980 model.

The pitch is the number of theoretical inches that the propeller will move per revolution. The higher the pitch, the further the boat should move, subject to slip.

Lower pitch gives more thrust but generally lowers the top end.

Your goal should be to reach around 5800 Engine RPM at WOT with your average load so that you don't lug the engine.