Plug A Built In Chemical Injector

Hi Everyone, just starting my business and purchased a Simpson 60843 4gpm with a 1:7 injector. I am concerned my SH mix is too weak when I used 10% straight. Can I plug the built in injector and add a High Flow?

Sure…others have done the same. Take the guts out of the current built in injector and cap it off. A lot of guys use the GP High Draw. Most also go down a size to help with draw rate due to length of pressure hose, fittings, etc. You want the 2-3 gpm/1.8 mm.

Appreciate the advice. Any suggestions on a method to cap it? The Barb is welded onto the AAA pump.

Can you snap a picture of the injector and post it? I tried looking online but can’t get a close enough view.

I’m an idiot; looks like it’s threaded. Looks like a brass plug should do the trick. What do you think? Thanks again!

Just remove the barb and there should be a spring and ball. Just pull out whatever will come out. Take the barb to the hardware store to match up the threads for a plug.

Most install their downstream injector right before their hose reel.

Not sure how much research you’ve done but there’s some great information on here so be sure to start browsing old threads. You’ll learn things you had no idea you needed to learn. Almost everyone that sticks around the forum and, implements the advice, ends up with an extremely successful business. There’s some great marketing advice on here too.


If I may also add…

The pros on here pointed out many of these stock injectors have a screw-in restrictor orifice. Take off the hose and look for it buried inside. Take it out for better flow.

My previous Simpson/Cat machine had one, yours may be similar.


Interesting. Thanks for the tip!

Bob @Pressure Tek told me long ago just to add another hi draw injector downsteam and do not worry about the factory built in injector. The only one active will be the one downstream. Bob was correct as usual.

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I would think that would cause the Venturi to draw in air and I would lose pressure for my soap stream. Thoughts?

Overthinking this, just add injector on downstream and keep on washing.

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I’ll happily do less work and not plug it. Thanks for the advice!

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Id plug it. Unscrew the old one and put a cap in the hole. Any hardware store will have caps id shoot for stainless steel.

We have dirt daubers here and they love to make red mud houses in holes like that.

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I have a small machine that i keep in trailer just in case or small jobs where its easier to set up, it is a simpson with injector. I didnt feel the need to go through hassle and take off. Works fine with normal injector and done fine i i ever need it.

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I simply added a short (1.5") piece of 1/4" tubing and put a screw in the end, blocking the airflow into the injector. That way I can take it of in seconds if I need to use it instead of the Adams that I added after the pump discharge.

On another note, my only concern now is that with my 3-5 GPM Adams adjustable flow injector will be sized wrong for 150’ of hose. (3.5 GPM PW).

Yeah, I would go one size smaller.

So if you go with 1-2 GOM down stream injector in a 4GPM machine you will get. Stringer mix? Or be able to use longer hose?

No, use the 3-5gpm.

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Yes, you will pull more and can use longer hose. You will be sacrificing flow by doing so.

Yes, you need the smaller injector to pull a decent amount of SH.