pump "exhaust primer" operation inquiry

[sgull]

I acquired this old early 60's era W.S. Darley (manufacturer) portable fire pump. I was cleaning it up, looking it over, rebuilt the carb, generally hoping to get it into running condition, maybe getting ready to try a start-up on the thing before long. I have some operating instructions but am missing info about this exhaust primer contraption accessory which is (as I understand it so far) to assist or even possibly pretty much completely eliminate in most general circumstances the need to do manual priming of the pump before starting the pump engine. But I don't quite get how it works without more instruction and thought I'd at least shoot my inquiry in that regard to folks here at the forum for some comment. Any comment/instruction/advice appreciated. thanks

 

[hunterguy86]

The exhaust primer uses the muffler to create a venturie for drafting water into the pump. In my experience, they never really work worth a darn.

What's your intended use for the pump? With some info, I could help you out with some general info on running it.

Oh, and more pics! I love old fire stuff.



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[shanny19]

http://www.fs.fed.us/t-d/pubs/html/98511317/98511317.html

Tired of Doing the Exhaust Primer Tango? is required reading for a forest fireman.

 

[sgull]

The exhaust primer uses the muffler to create a venturie for drafting water into the pump. In my experience, they never really work worth a darn. What's your intended use for the pump? With some info, I could help you out with some general info on running it. Oh, and more pics! I love old fire stuff.

My intended use for the pump, for one thing, is to pump out a manmade indoor cement-lined pond (no, not a swimming pool). It's fairly large and deep,9 feet at the deepest, a lotta "gallonage" anyway. Gotta pump it out at least annually for cleaning/maintenance. And a few other miscellaneous pumping uses I have in mind. I'm a maintenance person at a facility where we're trying to make do with whatever equipment we can manage with on a tight budget. Got a buncha hose with the pump too.
Sure it'd be great if you could help me out with some general info on running it, as surely more questions will be arising in that regard from me. More pics will be no problem too. So far it's been kind of an interesting "restoration" project, sort of been learning as I go in regard to the engine, the carb, and the general background of this piece of equipment. Been tinkering with it as I can in my spare time as kind of a side project. Glad to hear you're interested. Thanks. Will keep ya posted.

 

[sgull]

http://www.fs.fed.us/t-d/pubs/html/98511317/98511317.html
Tired of Doing the Exhaust Primer Tango? is required reading for a forest fireman.

Great! Thanks shanny19. Big time.

 

[RustnGrease]

Our antique fire engine at one of the companies i run with originally had an exhaust primer on it. It's a 1957 Gmc 450. We upgraded it to the new style electric primer a few years ago. Never heard much on how well it worked when younger/new.

 

[Nixon]

We have a darley pump at work mounted on a pick up truck for car fires in parking decks. It is newer, 1999 I think. It also has an exhaust primer, which works just fine. When I get down to that station I will try and snap a few pictures if the primer plumbing if that would help.

As far as operation, just open the water/primer valve. With the engine running, pull the handle over the exhaust pipe, creating suction until the pump is primed.

 

[sgull]

When I get down to that station I will try and snap a few pictures if the primer plumbing if that would help. As far as operation, just open the water/primer valve. .

Sure, snap a few pictures of yours too; I'd like to see it. I'm not really sure what/where the "water/primer valve" is on mine (yet). Can't be all that complicated. I'll be taking a closer look at the whole business again tomorrow, and probably take some more pics and try to get it figured out best I can (with help from ya all). Actually it could turn out being rather complicated. I expect there's gonna be some tango involved.

 

[gungatim]

what engine is that? looks like an old Briggs model 14 or 23? I've got a couple of those engines. If you haven't started it yet, make sure you've got spark. the magnamatic ignition coil disintegrates over time. There are fixes for it if you need, give me a shout.

 

[sgull]

what engine is that? looks like an old Briggs model 14 or 23? I've got a couple of those engines. If you haven't started it yet, make sure you've got spark. the magnamatic ignition coil disintegrates over time. There are fixes for it if you need, give me a shout.

Yep a model 23. Nope haven't yet tried to start it yet, but getting around to giving it a shot very soon I hope. Spent a lot of time recently "cleaning it up" (not apparent by the photo that's for sure) things like carb rebuild and general looking over, de-rusting, etc. At this point I think about all I need to do now is throw some gas in it and oh yeah I need to get myself a rope/cord with a knot in one end and a handle on other so I can wind it around the rope starter pulley/cup. I'll be checking for spark first, as you've mentioned. If not, will proceed to look over the coil situation. Great to hear you've got some experience with this engine; I don't but have been trying to educate/familiarize myself with it as I can. Thanks for the offer of help for fixes; and as far as that goes, you might as well go ahead and expect I'll be giving you a shout.

 

[gungatim]

for a rope starter, I like to save handles from broken snow shovels. you can pick them out of the trash. the nice thick orange plastic handles can be removed from the broken shove. and tie the rope up through the hollow portion. Makes for a nice comfortable pull-start handle that doesn't tear your hand up after trying to pull old motors 50 times in a row : )

 

[gungatim]

just PM me and I'll email you a pdf of the shop manual if/when you decide you need it. Those old Briggs models are a lot different then the modern ones since the 70's most people are used to, but they sure look cool with the old art deco fan shrouds painted up and detailed...

 

[hunterguy86]

Here are some high points on fire pumps.

They are all centrifugal pumps. They are great at pumping water but do not move air at all, thus the need for a primer of some type. The way a fire pump drafts water has to do with atmospheric pressure. When you activate the primer, it pulls a vacuum on the pump housing, allowing atmospheric pressure to push water from the source up into the pump.

For this to work, you must make sure that all of your valves and fittings seal really well.

To draft out of the pool, do the following:

1. Connect a rigid suction hose from the intake and place in the water. Open the intake valve of there is one.
2. Close all other valves.
3. Start the pump and idle it up.
4. Activate the primer and keep running it until you see the discharge gauge (if present and operational) show some pressure. You can also hear the pump stop cavitating.
5. Slowly open a discharge valve to help burp the remaining air.
6. Adjust throttle speed to desired pressure.

If the pump fails to prime, repeat steps 4 and 5 after checking for air leaks. If there is even a small leak it will affect your pumps ability to draft water.

As a general rule, once you have prime, always keep water moving somewhere. If the water gets stagnate in the pump housing it will heat up very quickly and damage the pump.

Do not run the pump without water in it, unless trying to prime, or pump damage will likely ensue.

If you have any questions don't hesitate to ask. I pump fire trucks and work on our fleet for a living so I can hopefully provide you with some help.


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[fhemm20]

Here are some high points on fire pumps.

They are all centrifugal pumps. They are great at pumping water but do not move air at all, thus the need for a primer of some type. The way a fire pump drafts water has to do with atmospheric pressure. When you activate the primer, it pulls a vacuum on the pump housing, allowing atmospheric pressure to push water from the source up into the pump.

For this to work, you must make sure that all of your valves and fittings seal really well.

To draft out of the pool, do the following:

1. Connect a rigid suction hose from the intake and place in the water. Open the intake valve of there is one.
2. Close all other valves.
3. Start the pump and idle it up.
4. Activate the primer and keep running it until you see the discharge gauge (if present and operational) show some pressure. You can also hear the pump stop cavitating.
5. Slowly open a discharge valve to help burp the remaining air.
6. Adjust throttle speed to desired pressure.

If the pump fails to prime, repeat steps 4 and 5 after checking for air leaks. If there is even a small leak it will affect your pumps ability to draft water.

As a general rule, once you have prime, always keep water moving somewhere. If the water gets stagnate in the pump housing it will heat up very quickly and damage the pump.

Do not run the pump without water in it, unless trying to prime, or pump damage will likely ensue.

If you have any questions don't hesitate to ask. I pump fire trucks and work on our fleet for a living so I can hopefully provide you with some help.


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^this

Also, build a little pressure (around 50 psi, more if your discharge is close to the same size as your suction) before opening a discharge 100%. Too much pressure drop at once and you will lose your prime, especially at lower engine speeds. Opening valves slowly will also help reduce this.

 

[sgull]

for a rope starter, I like to save handles from broken snow shovels. you can pick them out of the trash. the nice thick orange plastic handles can be removed from the broken shove. and tie the rope up through the hollow portion. Makes for a nice comfortable pull-start handle that doesn't tear your hand up after trying to pull old motors 50 times in a row)

gungatim check it out man. Thanks for that particular tip^. I'll be getting back to you regarding further fixes/inquiries, per your offer, stay tuned.

 

[sgull]

hunterguy96 and fhemm20, thanks, very helpful and very cool of you both sharing your expertise/knowledge as you've done for me here. I'll keep ya posted on this business as I progress.

hunterguy96, more pics to come, soon, I didn't forget. thanks again