First post! I’ll save my breathe and just say I love you guys and this forum has helped me tremendously.
I am looking to upgrade my 4gpm/4000 psi cat pump on my gx 630. I have the northern tool trailer that everyone says to run away from. Its made me enough to upgrade to a new trailer but I think I want to hang on to it and put my brother to work washing all the vacant houses a management client of mine always gives me. My question is what kind of pump am I able to upgrade to with this motor. I am aware the heater cant handle more than 4gpm and plan on bypassing it. So how big can I go? I would love an 8/3500 belt drive but im not sure that is possible or if its even worth my time. My local dealer wasn’t sure and still hasn’t gotten back to me with an answer. So I came to the real pros for the answer. What would you guys suggest? If there is a thread on this, please point me in that direction because I haven’t had any luck finding the info I need. I included a snapshot of the specs for reference. Thanks in advance.
My new 630 has a 5.5/3500 belt drive on it. You could put a gear drive on there, they may even have something like a 6/3000 available.
And frankly I’m surprised they slapped a 4/4 on a 630. Heck my gx390 had a 4/4200. Your motor is capable of a lot more than 4/4.
Most important question is what are you going to be cleaning? Houses, concrete, commercial buildings, trucks, or?
I like to think they left me room to upgrade because they know what’s stock is crap lol. I would love a gear drive, I’m just not sure of the brand or size needed.
Houses, like I said.
Then you want gpm over psi. I would go with an Udor 8gpm from Dultmeier.
Or get a 5.5/3500 and be able to do concrete if needed.
As you have a direct drive now, a gear drive reduction unit will probably be your less headache route as they just bolt on to the motor instead of running a separate belt system.
I’m still fairly new though, these other guys know a lot more than I do.
Ya, that’s what I’m thinking but I just don’t know which model to get that will work properly with this motor. I just spoke with my supplier and he is pushing the Comet 8gpm/3000 psi belt drive. Comet is the brand they sell ofcourse and I know there is better quality. I would need the conversion kit and to probably turn the motor as the pulley system won’t fit as it sits now. Who would be more helpful to call in this situation, Udor or Dultmeier? A gear drive Udor would be amazing and would make my northern tool setup quite the little sleeper rig lol
If you are going to go Cat just get an Allison from Envirospec. They are just rebranded Cat pumps. With a 630 I’d go 8gpm 3500 as a minimum. That engine will power it and for house washing it’ll be more helpful. Now if you said you were doing overwhelmingly concrete I might push for 4k psi.
I ve found a 10gpm beltdrive pump for about $518. Industrial pump. Thats an option Ive been contemplating myself.
Sure about that? It’s 20hp.
This is what I would personally put on a gx630 if upgrading the pump. The gear drive will pull water much better than the Cat pump you had on there. It’s 8gpm and 3k psi. You’ll get a little less than 3kpsi but it will be a beast washing houses and you’ll still be able to wash concrete. I’ve ordered an Udor pump from Sprayer Depot before and it worked well.
…pretty sure that would be down to the heater size 
That bolt on Udor pump/gearbox would be perfect as @Barry1 suggested 
This is exactly what I was looking for! thank you!
That thing will even bolt up without having to turn the engine like I thought I would have to. Any recommendations on the unloader setup?
Order an unloader block from Pressure Tek with a whip line and mount on frame of trailer or somewhere that’s stable. It depends on what type unloader you like whether flow actuated or pressure trapped. Some swear by the K7s…I still use the cheap pressure trapped VRT-3 ones and keep a spare. Haven’t had any issues with mine.
