how much RPM is safe? : LUSENET : Junkyard Wars : One Thread

What is the max RPM an 8 HP 16 year old briggs and stratton vertical shafted single cylinder angine can spin at without the governor? how fast is safe and how fast before explosion? i need to know because i have a go-cart with such an engine and i want to speed it up a bit so if anybody knows please do not e-mail me post it on the forum. thanks

-- Gollum (, June 21, 2004


You'll have to use your better judgement on revving it too high. I've never blown up any Briggs simply from spinning it too fast. Most likely the valves will float before you can throw a rod. The smaller the engine, the more rpm it can take also. Be aware the flywheel could explode and with a vertical shaft engine, it will go in every direction.

-- Jim (, June 25, 2004.

I wouldn't spin that thing any faster than about 5000 RPM. I've seen 5 horse briggs let go. In Jr. Dragsters we spin then in the 8000 to 8900 RPM range, but that's with aftermarket rods and billet flywheels. If you plan to spin that 8 horse up very high, you'd better put at least 1/8" aluminum between the motor and the back of your seat. You wouldn't want to catch a piece of exploding flywheel in your backside.

-- cal (, June 29, 2004.

I too have a old briggs about that old and I am really considering getting a new topend for it because it burns oil and i wanna be able to take the govenor off it and rev the piss out of it.

-- I'm crazy but i aint dumb (, January 13, 2005.

Above 14500RPM does well and won't blow up for few seconds...

-- Gollum (, January 19, 2005.

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