No Pressure

This may be beyond the scope of this board (I am too new to all of this to know). But here goes:

  1. Went to start the 4000 psi/4 gpm Kohler engine and it was very hard to start. Once started, it would not stay on. Was told to pull the pump off and try starting. I did that and now it is easy to start.

  2. Engine starts easily but pressure is extremely low (3800 psi when not pulling the trigger, 900 psi when pulling the trigger). Changed tips from a white tip to a 0-degree. Got a little better pressure when pulling the trigger. However, the higher pressure would not last before it went down.

  3. Started the engine - still no problem… absolutely no pressure! No matter what I do, there is no pressure registering on the pressure gauge. Water from the garden hose flows through and out of the tip.

More notes: I just put the pump back on. Very high pitched squeal when I pull the trigger but I do have some pressure back. I noticed a grove in the cam shaft and a groove on the pump receiving end but don’t see anything that would connect the two. I don’t want to confuse the issue but is the loud squealing the camshaft spinning around the pump part without doing much? Wish I made more money before this quit working… I could pay someone who knows what they are doing!

I filled a 5-gallon bucket with the garden hose and it took 24-seconds so I have good water pressure to the machine.

This is a Kohler 12 hp model CS12T with a General Pump model TX1510A if that helps. It has been used three times for a total of about 12 hours. It was not used before I got it. The oil is all good and is not milky or anything like that.

Any help would be greatly appreciated but speaking as if you are speaking to someone who doesn’t understand much about pumps will help…

Thank You In Advance - David

It could be the unloader, I had the same issue with a brand new machine. Pinch the bypass hose with trigger pulled, if you get pressure then its the unloader.


There’s no bypass hose… The unloader has a relief valve. Now what?

Thanks for your help - David

The groove is called a “Key Way” there should be a “Key” which is a small square piece of metal stock mating the male crankshaft to the female pump. If the key is not there crankshaft will just spin…no or very, very little water. But you still have a problem, what sheared the key?? I’d say the problem is your unloader.

Thanks GuyB, I figured as much. What worries me is where did the key go??? I’ll be ordering a new unloader in a couple of days.

Hope you guys are doing okay with the wind and such.

Sometimes they just shear off and spin out. You may just have some trash in your unloader, you may be able to take it a part and clean it, but it never hurts to have a backup.

No worries up here…just wind. I hate it for those further North though.

With three jobs pending, I figured I should just get a new one and teach myself how to work on the other one (any clues and hints are always appreciated). Figure it is part of my job to know how to work on my equipment (at least general maintenance) and that will give me a working spare (as long as I don’t mess it up).

I lost two houses within two weeks due to two hurricanes! John T is probably having a grand time. Glad to hear you are doing well there in Fayetteville. When I was stationed there, the worst I ever saw was a big snow storm… That was funny.

WOW! This is exactly what I need to know! Thanks for sharing!