Making the switch to 8gpm

I’m currently running a 2500/5.5 belt driven machine. A friend of mine bought a 8gpm, comet tw8030 electric start Honda motor at an auction . He’s asking 2k for it but I’m shooting for 1200. It’s older, but runs good and the pump/ motor oil both seem to be relatively clean. My question is, aside from getting a larger buffer tank and new j rod tips. What else would I need to swap out ?

Depending on what you used to plumb your current machine, maybe larger supply line from the tank. 1” should be sufficient if it’s not too long a run or too many elbows/restrictions. Though a lot of guys do recommend 1.5” for 8 gpm.

You should also have a spare unloader for it.

Apart from those two details, and the stuff you mentioned, I think you should be good to go.

I would probably go up to $1800 for an 8gpm machine that I knew was in good working order. I try not to spend more than 50% of original retail for used equipment.


You probably will need to change your DS injector as well or the orifice size.


I use 1" supply line from buffer with no problems. @TexasPressureWashing is right. Depending on pressure hose length you’ll most likely need different DS injector. I use 2.1 GP High Draw for my 8 and 1.8 or my 5.5 gpm both with 150’ of hose. The 8 will pull soap with the 1.8 injector but you can see a significant loss of flow.

1 Like

I currently have the GP 2.1 hi draw on my 5.5 GPM along with two spares so I Planned on doing the bucket test to see where I was at in flow and ratio. 200 ft of pressure line is the most I have ever needed. I currently have 1 inch line from the buffer as well but I’ll definitely look into getting some 1.5” for the new set up.

1 inch supply hose, 2.1 injector, different jrod / quad rod tips with larger orifice, make sure spray gun can support 8 gpm (most do), a float valve for the tank is a good idea. Surface cleaner 25025 tips are good for more flow. If you x jet, get the one meant for 8 gpm.

1 Like

Thanks everyone for all your help. I currently run a 20 inch whirl a way. It’s in very good shape so I would like to try and get at least another season out of it. With it being a smaller size in comparison to the machine would the 25025 size tips still be the appropriate size ?

Size of the surface cleaner has nothing to do with nozzle size. Nozzle size has to do with psi of the machine. The only thing surface cleaner size will affect is how fast you can move. Generally, the smaller the surface cleaner the faster you can move. There is a sweep spot for maximum efficiency though.

1 Like

I run 3/4” supply to my 8gpm, it isn’t starving.

You’re not helping it any either. Switch to a 1" when you get the time.


Roger that.:+1:

Went and ran the machine today. We settled at 1200 with a 50ft section of 2 wire, wand, boat tank and battery box. It ran great however, The pump has a small leak on the front. I’ll post pictures or a video of it when I go pick it up and get it back home, worst comes to worse, I’ll be putting a new pump on it over the winter before mounting it to my trailer.

1 Like

Can’t beat that price if it runs. The leak is likely just an o-ring, seal, or loose fitting. Will have a better idea once you post a picture and point out where it’s leaking from. Might not hurt to just get a rebuild kit for the pump. Although, even if you picked up a Udor or GP you’re still only $2200 into it. Not bad at all.

What size is the Honda? How old is it?

It’s a gx670 electric start. I believe it’s an 02. Made by BE. the guy I bought it from bought it at auction years ago to use for cleaning his track loader tracks out. Been sitting in a garage for the last 2 years. He did have the carb rebuilt recently l.

My overall plan is to, if it’s possible, run my 5.5 and this 8gpm of one 225 gal buffer tank. I’m currently a one man operation with my 5.5 and it works well for me. However a friend of mine got hurt in an accident and is dying to help me out because it’s outside work that isn’t too physically demanding. So on days I’m doing municipal Water supply homes I’d like to have him tag along. I’ll soap my 5.5 while he follows behind rinsing.

1 Like

Someone posted this to a FB group. Good deal

Might want to remove the head and wipe since vaseline on the ceramics. I’ve fixed a small drip that way.

That’s a good price

Brought it home today.

The last photo is where the leak is. If your looking at it from the front of the pump. Is on the lower right corner where the pump head mounts to the body of the pump. I’ve looked up a reseal not which wasn’t too bad. But due to its age and not being used much lately would you recommend just putting a new pump on, fixing this one and keeping it as a back up ? Honestly I’m not even sure I need an 8gpm. So far just doing residential my 5.5 has done everything I’ve asked it too without an issue.