[Richard]

My generator would require several attempts to start after sitting for a day or more. It would start and stutter, start and stutter, and finally catch. I changed all filters with no change in the behavior. Gordon helped me wire the pump so I could prime it from inside switches. That helped for a while, but the hard to start was getting worse with time. It changed from a nuisance to a situation where I could imagine it not starting at all. 

It was pretty evident that it was not maintaining fuel pressure. I suspected that the pump was allowing the pressure to leak away when the generator sat for any length of time.

It took a call to Carter to confirm a new part number for the old pump, but here is the new Carter pump number .

http://www.amazon.com/gp/product/B000CIQ...ge_o01_s00  This is for the Kohler genset with Yanmar engine. 

I am happy to say that after sitting for week, the genset started with the first touch of the switch.

[Erniee]

our generator likes a little warmth to keep her going, initially. So- I depress stop button and then it fires right up.

[Richard]

I want to follow up on this post. My good results continue with the gen starting as soon as I touch the start switch.

The reason for he follow up is to report that the new fuel pump also fixed a vexing problem that I would not have connected to the pump. From time to time the genset would smoke profusely. It didn't seem to be related to load, outside temp, or phase of the moon. I changed the filters twice. I took the injectors out and cleaned them with no change. I would load the genset up to "burn off the carbon", with no change in smoking. The smoke was black, not blue or white.

It hasn't smoked since I replaced the fuel pump. I can make up theories why low fuel pressure would result in black smoke, but it don't really know why. I'm just glad the tugboat syndrome is gone.

[DK on the road]

I'm having a similar problem and I'm thinking fuel pump.

When the tank is full, it will start and run endlessly. At something less than 1/2 a tank, I've never had it below 1/4 tank, it stumbles and drags down, then recovers, after several cycles of the RPM dropping and recovering, it will stop.

I thought, initially that it was the little filter, but it only had 50 hrs on it. So I got a bright Idea and added a 2 micron filter with a water trap from Racor between the tank and the electric pump. I've had this Racor unit before and it's really effective at water separation and filtering. Now I'm thinking the little electric pump may have been rewired by a previous owner to only prime the motor and not run full time.

I see an older electric pump disconnected and abandoned in the genset area. So Prior work may have tried to solve a similar problem.

Today, I'm going to add a few "Tee's" in the system and check for pressure or vacuum. I hope to have 5psi of better prior to the Engine and I'm curious what the vacuum is prior to the electric pump This will tell me if I've added too much filter, or the electric pump is working or wired wrong.

Your Thoughts ?

[Richard]

If your filter is like mine there is a NPT threaded port on it. Per gordons suggestion i put a pressure gauge in that port

[bestgenman]

Here is a personal take on fuel pumps and filters.  It differs from many manufacturer's position in that many primary filters are installed on the suction side of the lift pump.  This is to protect the pump from debris as it's suction is from the tank generally.  My opinion is; there should be a strainer only on the suction side and the primary & secondary filters on the pressure side.  The reasoning is because it is so easy to draw air on the suction side which leads to so many fuel system problems, including low fuel pressure.  Yes, the strainer can cause air inclusion however,  it is not serviced as frequently therefore not as problematic.   

As Richard says, a fuel pressure gauge on the pressure side gives a quick visual of system pressure.  I hardly ever change the secondary (annually changed)  since the primary,  Racor in my case, receives the brunt of dirt and water.

[DK on the road]

I added the Racor to the suction side of the pump hoping to not agitate the fuel/water mixture and get it before it was ran thru the pump. I understand the ability to pull air on the suction side and didn't think I could if I built it correct and tight. But I also have said I should fire my mechanic (me).

What should the pressure or Vacuum differential be on a filter before serving ? Maybe each filter has a different limit ?

Does anybody know how high the pick up is off the bottom of our fuel tanks ? 20% off the bottom, 10% ?