I bought a Husqvarna mower with a Kohler SV600S that had a crack in the block that the original owner had repaired. The engine runs perfect but most of the oil will leak out within a week. I found a replacement engine which is the SV590 that came from an MTD with a broken frame. I swapped the engines out and everything is perfect except I can not keep the engine running. One thing to note is my Husqvarna gas tank is in the rear and the MTD gas tank is mounted just behind and above the engine. On the SV600S, it has a fitting on the top of the crankcase that is connected to the vacuum line on the fuel pump. The SV590 engine does not have that fitting on the top of the engine. However, on the SV590, there is a 1/4 in breather tube that runs from the valve cover to the air intake housing, with a smaller hose that runs from the air intake housing up to the fuel pump mount but was not connected to anything when I bought the mower. Do this tube and setup serve the same purpose as the fitting on the top of the SV600 and should I connect the vacuum line to it? I have tried it but the engine still will not continue to run. When I spray gas in the carb, it starts immediately and runs strong for a couple of seconds then shuts down. There doesn't seem to be any fuel pumping out the carburetor hose from the fuel pump when I crank the engine over. So, I don't know if the fuel pump is bad or if I need to find a different way to connect the vacuum line.
Fuel Pump Not Working After Engine Swap SV600 to SV590
- Thread starter raider820
- Start date
Richie F
Well-Known Member
- Joined
- Aug 8, 2019
- Threads
- 19
- Messages
- 276
As long as the fuel pump gets a vacuum signal from the engine crankcase it doesn't matter where the hose is connected to.
There are some that connects to the valve cover, others go to the crankcase it self.
If you want install an electric pump that puts out like 3 psi.
I think the carb can hold back 5 psi, but I could be wrong on that.
Gravity feed to the carb is at atmospheric which is 15 psi.
There are some that connects to the valve cover, others go to the crankcase it self.
If you want install an electric pump that puts out like 3 psi.
I think the carb can hold back 5 psi, but I could be wrong on that.
Gravity feed to the carb is at atmospheric which is 15 psi.
Hammermechanicman
Lawn Addict
- Joined
- Jan 10, 2020
- Threads
- 53
- Messages
- 3,515
Not 100% sure from your description what you have but the fuel pump needs to be connected to a line to the crankcase. If you you connect the hose from the valve cover to the fuel pump it should pump fuel.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 64
- Messages
- 24,705
The line you have connected to is the breather and has a reed valve on it so it can not be used to power an impulse fuel pump because the pump needs both a blow & a suck but the breather only blows.
So you will need to put a new take off barb to power the pump
Good spots are the dip stick tube or side of the rocker cover.
So you will need to put a new take off barb to power the pump
Good spots are the dip stick tube or side of the rocker cover.
The smaller tube going up by the fuel pump mount would be the vapor recovery line that would connect to the top of the fuel tank. It is a low vacuum line to draw fuel vapors for EPA requirements. Look at the top of the SV590 and it may have a removable plug in the same location as the fuel pump barb fitting on your old engine. If so then unscrew your barb from the old engine and install it into the new engine.
Richie F
Well-Known Member
- Joined
- Aug 8, 2019
- Threads
- 19
- Messages
- 276
That's what I just said.
I wish that was the case, but on the 590, the spot is a raised cast molded spot but was never drilled.
Thanks everybody, I think I will try connecting to the valve cover and see how that works out. If that doesn't work, I will look into connecting to the dipstick tube.
Good news, I am up and running. I originally tried replacing the breather hose in the valve cover with the line to the fuel pump. After the mower ran for about 3 minutes, it blew the dipstick out. So, I figured the fuel pump didn't allow enough pressure to bleed off causing and excess build-up. So I drilled an additional hole in the valve cover and reinserted the breather hose and connected the fuel pump and it works. Thanks for the help.