changing 3000 rpm to 800 rpm

Feb 02, 2007 4 Replies

I have a 5 hp briggs and straton gas engine. The dealer said it turns



3000 rpm , at full throtle. I can't find it on engine but I assume he is correct. I have a 3 inch pulley on a cintrifical clutch on drive shaft. I need this engine to turn a pump at 800 rpm. Can someone tell me what size pulley I need to on my pump? Any help would be greatly appreicated.

Tom Richards



The diameter of the pump pulley needs to be 3000/800 times the diameter of the motor pulley.

11.25" driven pulley. 11 gets you in the ballpark

Let's see if I'm thinking correct, (I'm sure if I'm not someone will let me know). You have asked a ratio question, simply divide 3000 by 800 to get

3.75. Multiply this by the 3 inch pully to obtain the size of the pully you need on the pump - 11.25 inches.

T Carter

Two excellent sources for that sort of info, are the "Pocket Ref", and also the online or paper version of a McMaster-Carr catalog.

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