have a question on a sp22 vaccum pump

[miller maple]

i have a sp22 pump that im useing my ? is i put a gas motor on it and i was wondering at what RMP's that pump is posta be run at. today i was running it and i was getting around 17" out of it is that about right for that pump? and is it normal for the top of the pump to get warm.

[Dennis H.]

A good rpm for the pump is around 480-490 rpm's. Some have run it at a higher rpm and had no troubles.
As for inch of vac, you should with out any problems run that vac pump up in the 20's.
I ran mine right at 23" and never had any kind of problems. Yes they will get warm to the touch but they will be fine.

[miller maple]

ok i put a 13 hp gas motor on it and im running it a idle should that work ?

[mapleack]

Factory electric set up is a 1725 rpm motor with a 3.25" pulley on the motor, pump rpm at 475 with that pulley. Assuming your gas motor tops out around 3k? If you had the same size pulley on it you'd be looking at half throttle. If you're getting 17" on a dead headed pipe you need to run it faster. Providing the pumps in good shape you should dead head at over 24", just can't run it that high all the time or it'll overheat. Like Dennis said, warm/ hot to the touch is normal. I can't hold a hand on mine for more than a couple seconds. What you don't want is so hot that it sizzles! :)

[miller maple]

Ok ya I'm just wondering cause I don't wanna burn the pump up. I have a 4" pulley on the engine and a 14" pulley on the pump

[mapleack]

With those pulley sizes if you ran your gas engine at 1725 your pump rpm would be 493. If you ran it at 1,000 rpm your pump rpm would be 285, which might explain being at 17" vac.

[miller maple]

Well I just tightened up my vacc regulator now I'm getting 24'' is it normal for the pump to smoke a little white smoke? And should I take the pump apart and clean it or not it was sitting in my grampas barn since 95 I drained all the old oil and put new in just don't know anything about these pumps

[mapleack]

A little mist / gray haze out the exhaust isnt unusual. Just so its not "sizzle" hot on the head. I'd watch the oil in sight tube, if it doesnt look filthy I wouldn't worry about tearing it down. I change the oil in mine every season. Usually have to add a little through the season but not much.

[tuckermtn]

I run a very small pulley on a 6.5 hp subaru/robin motor. I don't know for sure the diameter, but my guess is it is closer to 2". run the vac regulator very tight and the motor very close to idle, i.e. very slow. On a tight system the lower RPMs will allow you to run vac levels in the mid 20's without getting the pump head sizzling hot.

[Dennis H.]

If the oil looks nasty in the sight glass run it for awhile to get the oil hot nd then drain it all out and put in fresh oil.

Like mapleck said a little misting/smoke is normal. On warm day you will even get some dripping. I put a bucket under the exhaust to catch as much as possible.

[miller maple]

Ok thank you very much ill give it a shot