Horseplay82 14 #1 Posted April 5, 2016 I have a 1968 commando 8 with the kohler k181s! Ive rebuild the carbuerator and the fuel pump! I tried to start it and the pump appeared not to be pulling the fuel through! Could i have done something wrong, bad diaphram if so are new diaphrams available, if not can i still use the original carb? 1 Share this post Link to post Share on other sites
Shynon 7,427 #2 Posted April 5, 2016 Diapthrams available on , I have used several of them with good results. When you rebuilt it did you remove the check valves, if so are they installed the correct way. 2 Share this post Link to post Share on other sites
Horseplay82 14 #3 Posted April 5, 2016 I thought i installed everything correctly. Is there a special way? Share this post Link to post Share on other sites
Ed Kennell 35,151 #4 Posted April 6, 2016 Is the fuel shut off valve open ? Share this post Link to post Share on other sites
953 nut 51,029 #5 Posted April 6, 2016 4 hours ago, Horseplay82 said: Is there a special way? There is a check valve on the inlet and on the outlet. Each valve needs to open in the direction of fuel flow or no pumping will occur. Share this post Link to post Share on other sites
ELECTRORIC 228 #6 Posted April 6, 2016 You might try priming the pump Share this post Link to post Share on other sites
Ed Kennell 35,151 #7 Posted April 6, 2016 To test the check valves in the pump. You should be able to blow air through the pump by blowing on the inlet or tank side, but not when blowing on the outlet or carb side. 2 Share this post Link to post Share on other sites
WHnoob 21 #8 Posted April 6, 2016 I've used the rebuild kit from Then and Now Automotive: http://then-now-auto.com/kohler-fuel-pumps-2/ It includes replacement check valves along with the diaphragm. The other problem with mine was that the bottom casting was warped enough that it didn't fully seal against the diaphragm. I had to hammer it flat enough to stop spraying fuel out of the seam. 1 Share this post Link to post Share on other sites
Ed Kennell 35,151 #9 Posted April 6, 2016 Do you have a good flow of fuel at the pump inlet? If you do, then pull off the fuel line at the carburetor and while holding it in a container, crank over the engine. If the fuel pump is working, you will see a strong spurting of fuel. 1 Share this post Link to post Share on other sites
Horseplay82 14 #10 Posted April 6, 2016 My fuel pump doesn't seem to be mechanical Share this post Link to post Share on other sites
Ed Kennell 35,151 #11 Posted April 6, 2016 If it is vacuum or mechanical operated, It should still pump when you crank the engine over. If it is electric, it should pump when the ignition switch is on. Did you verify you have fuel at the inlet to the pump? Did you then check if the pump is working by pulling off the fuel line at the carburetor and cranking the engine? Please perform these two simple checks, then we can determine if the pump is or is not working. Again, no pump will work if there is not a supply of liquid at the inlet. 1 Share this post Link to post Share on other sites
953 nut 51,029 #12 Posted April 7, 2016 6 hours ago, Horseplay82 said: My fuel pump doesn't seem to be mechanical If it is a vacuum pump it will require a good seal where it attaches to the block. A slight vacuum is created when the piston goes up and pressure when it comes down, that in turn moves the diaphragm and if you have a supply of fuel to it and the check valves are correctly installed the movement of the diaphragm will pull fuel in and push it out. Share this post Link to post Share on other sites
Horseplay82 14 #13 Posted April 25, 2016 Can i do away with the fuel pump and block off where it goes on to the block? Share this post Link to post Share on other sites
Horseplay82 14 #14 Posted April 27, 2016 Any help would be greatly appreciated Share this post Link to post Share on other sites
pfrederi 17,043 #15 Posted April 27, 2016 10 minutes ago, Horseplay82 said: Any help would be greatly appreciated Bypass the pump...keep the tank half full or stay off long hills and you should b fine. No need to remove the pump itself. Cap the in/out so you do not suck trash into the crankcase if the diaphragm is compromised. Share this post Link to post Share on other sites
Ed Kennell 35,151 #16 Posted April 27, 2016 Can you verify there is a good free flowing supply of fuel at the inlet to the Pump? If you do not have good fuel at the pump inlet, you must find out what is blocking the supply. It could be collapsed fuel lines, dirty fuel filter, tank shut off valve closed or blocked, blocked screen inside fuel tank. If you have a good supply to the pump and the pump is still not working, follow Pauls advice and try bypassing the pump. 1 Share this post Link to post Share on other sites
Horseplay82 14 #17 Posted April 27, 2016 Thanks guys, could i make a cover plate to go over the opening where the fuel pump bolts to the block and if so do i need to make it with a breather port? Share this post Link to post Share on other sites
pfrederi 17,043 #18 Posted April 27, 2016 No... crankcase breather is a separate thing behind the plate above the pump 1 Share this post Link to post Share on other sites
RedRanger 1,468 #19 Posted April 27, 2016 On 4/25/2016 at 3:11 PM, Horseplay82 said: Can i do away with the fuel pump and block off where it goes on to the block? Yes. No breather needed. Some people even tap the cover for a vacuum line to run a new style pump. Share this post Link to post Share on other sites