gas engine powered SP22

[davey]

If anyone is running a gas engine on an sp22, can you post the HP, rpm range and pulley size you are using if you know them?
thanks
Dave

[G.Rainville]

The piston pump I use is a BB-4,I believe it's an older version of the sp-22. The only gas motor I had was a 13-hp Honda but the surge dealer in my area said that 5 to 7 hp would be enough. The pulley on the motor is about 3" and the one on the pump is approx. 14". The surge dealer also told me the key was not to go over 400 to 425 RPM on the pump shaft. I was able to do this by adjusting engine RPM. This seemed to work fine I pulled 24 to 26 inches of vac for most of the season. Later in the season when it was really warm out I opened the regulator to only pull about 20 inches of vac. so the pump wouldn't run so hot.

[tuckermtn]

for an sp-22 you want the pump RPM range to be between 390 to 420.

for an electric 1750 rpm motor that is a 3.5" pulley on the motor and 14" pulley on the pump. So I think Rainville's numbers seem to be about right if your gas motor rpm's are near that...

I ran a BB4 last year on a 5hp honda. wouldn't reccomend it, but do able. A 5hp should pull a sp-22 fine. 7hp would be extra insurance.

[lpakiz]

I used a 3.5 HP Tecumseh from an old asnowblower on a SP-11. Worked fine. 2 1/2 to 3 inch or so on the motor. 22-23 HG no problem