Engine stalls at 20?

[The Sweet Spot]

I just rebuilt a Massport Universal pump, and wow will this baby suck. We started it up for the first time attached to our mainline. As soon as the gage hits about 18 - 19 " the engine stalls. Even at full throttle! We bought a 6.5 hp motor to run it and followed every ones advice. I know that I could put a vacuum regulator on it and decrease the vacuum till the engine runs. I would like to pull as much as possible so this seems wrong to me. Is my engine too weak? I was trying to save money and bought an Iron Horse engine from norther tool. It runs great but is it too small?
Any advice would be great
Thank YOU Troy

[BAP]

What are you running for pulleys on motor and pump? Is it turning the pump too fast? Could be you need to put a smaller pulley on the engine to "gear it down" which will increase the power it has to turn over the pump.

[BreezyHill]

Is this the M3, M5 or M7 pump. If it is a M3 you could possibly change the pulley size and have it work if an M5 or 7 then the motor is to small, but there is a trick that I have had work well for me. A larger driven pulley than the 10" or 12" standard is going to really increase the speed you will need to run the motor at so you will be going thru considerably more fuel than a larger motor just loafing along at over an idle.

If you look on ebay at digital rpm testers they are really cheap not from Asia and a really good tool so that you are not over speeding the pump.

Remember that even at 17" you will be getting around 170% of you gravity production from the system. So this could work to make some extra $$$ to buy a larger motor next season.

[The Sweet Spot]

First: Bap I am running a 2.65 pulley on the engine, and a 12" on the pump.

Second: Breezyhill It is a M5, I was told it came with a 3 hp motor.

I looked up some old threads and got the idea that a bigger engine would be over kill. I bought one that was bigger than I thought it needed. Thinking that it would just lumber along not burning much fuel, at about 1/2 throttle. Now I am thinking that the engine is too small. Was I told incorrectly, did it come with a 3 hp engine? I just bought the material to build a vacuum regulator. I have it put together now, but not installed. Tonight I ran the pump for about 4 hrs at almost full throttle, but getting 15-17 at the releaser! I will upload pics as soon as I can figure it out. What size engine do I need to run this pump at capacity? I do have a Kohler 13 hp with a tapered shaft. It is a 2 cylinder so I'm not sure of fuel consumption. Also I would need a different bushing inside the pulley. I have completely rebuilt the pump and have it running through a oil reclaimer homemade with PVC. Then it runs through a spin on filter, and on to the transmission radiator. From there I have lines running to the inlet side of the pump and both bearings. I am not getting any fluid being pulled in through the lines to the bearings. They are getting fluid. I pulled it apart to make sure. Do I need to put a valve to the inlet side, limiting the pull through here? Thank you both for your response. I have ordered a 2.2" pulley for the engine. It will save more in fuel than it costs.

[maple flats]

On my Alamo pump I discovered that when I went to a smaller pulley I needed a double pulley on both the pump and the engine to get enough friction to drive the pump. Will yours be a double? Also, the relationship between a 3 HP electric motor and a gas engine does not translate to a 6.5 HP gas, while the normal ratio in 1/1.8 from electric to gas, a gas engine is rated at 3600 rpm. That speed may be too fast for the Massport pump, thus you need the bigger engine so it can run slower and still have the power needed. For a vacuum system you usually want to go 3/1, gas/elec. The 13 will make more sense than buying a 9 HP. Find out what RPM your pump should run at, and then using the Rpm meter Breezy mentioned. Then use a bigger engine pulley and run the engine slower, about 1200-1800 rpm will still give the power needed and save gas.

[BreezyHill]

First: Bap I am running a 2.65 pulley on the engine, and a 12" on the pump.

Second: Breezyhill It is a M5, I was told it came with a 3 hp motor.

I looked up some old threads and got the idea that a bigger engine would be over kill. I bought one that was bigger than I thought it needed. Thinking that it would just lumber along not burning much fuel, at about 1/2 throttle. Now I am thinking that the engine is too small. Was I told incorrectly, did it come with a 3 hp engine? I just bought the material to build a vacuum regulator. I have it put together now, but not installed. Tonight I ran the pump for about 4 hrs at almost full throttle, but getting 15-17 at the releaser! I will upload pics as soon as I can figure it out. What size engine do I need to run this pump at capacity? I do have a Kohler 13 hp with a tapered shaft. It is a 2 cylinder so I'm not sure of fuel consumption. Also I would need a different bushing inside the pulley. I have completely rebuilt the pump and have it running through a oil reclaimer homemade with PVC. Then it runs through a spin on filter, and on to the transmission radiator. From there I have lines running to the inlet side of the pump and both bearings. I am not getting any fluid being pulled in through the lines to the bearings. They are getting fluid. I pulled it apart to make sure. Do I need to put a valve to the inlet side, limiting the pull through here? Thank you both for your response. I have ordered a 2.2" pulley for the engine. It will save more in fuel than it costs.


M5 takes a 5Hp motor and should run at 1000 RPM. I would try the Kohler as you have it.

Be careful of a pvc reclaimer. The exhausted on a pump can very hot and cause pvc to warp and sag.
Spin on filter is a great cooler also and good oil cleaning.
Tranny radiator would not be needed on a metal reclaimer of sufficient size, as the reclaimer will cool the oil well.
It is pretty hard for oil to get pulled thru a filter, lines, and a tranny cooler if there is any kind of size restriction. If you didn't use good vac oil then it is a foamed oil issue.

I lost a pump yesterday from some foamed oil plugged the oil lines and the pump went super nova. She was at 358 when I got to it after it popped the fuse. She is running again but will have to got to the bench for further tooling...something rubbed on the face cover and it is only making 20" vac now. So I have to pull it out and put in another. And I don't have time for that right now.

I have a big body Alamo that just needs a wash down and oil lines changed from plastic to copper and she should be good to go.
The M3 is in need of a full tear down and cleaning...she has a 3 hp motor on her.

I think the kohler is going to be your best option right now. There is an equation that relates gas to elec Hp but the issue we have is we like to run the motors slower and are out of their horse power band...thus we need larger motors than the standard option.

If doing the math for the size of the motor pulley the M% had a 9.5" pulley as stardard equip.

I would also suggest a digital rpm meter off ebay. Got one Monday and it is pretty handy. Those off speed surge motors are that way for a reason. Standard size pulleys spin the pump to fast with a standard rpm motor. Next size smaller is much slower.

Good Luck!

Ben

[The Sweet Spot]

Thanks for all the information. I have been able to maintain 18" after some fine tuning. We tried to use the adjustable motor frame on the pump. Getting a lot of belt flap so I installed a friction pulley. My belts may be too long 66". But getting the motor closer to the pump is not really an option. Next year I will weld a solid frame with a friction pulley. We will be installing a larger motor (possibly the Kohler) next year. The pulley came in yesterday so I will be changing it right away. I think I will be pulling over 20 with no problem now. Not running in the power band of the engine, but not terrible either. 1000 rpm's really? Wow I thought I was running it too high at about 900! BreezyHill how many of these do you have. You sound like your experienced with them. Thank You for all the information. The PVC oil collector is not working as I had hoped. I have been told that it is possible to collect all the oil in the exhaust. Is this true? I am blowing out about a quart a day. The other problem is that all of the sudden the belts will throw. Both at the same time and with no warning. I have sat and watched for way too long with nothing going wrong. Later I will go to check the pump, and can hear the belts are off before I even get there. I am using a double shive pulley. This isn't good as I have to work tomorrow and will need to start it up early and have it run all day till I get home. Has any one tried a chain driven pump?