FVan 3 #1 Posted Monday at 10:46 PM I have no gas being pumped by my Kohler K 103 fuel pump. I replaced the diaphragm, the holes in the new one didn't line up so I had to recut them and I had to also modify the stem. The new diaphragm did not resolve my issue and plus now it leaks gas. I cannot find an exact replacement one. Any suggestions would be appreciated. 1 Share this post Link to post Share on other sites
Ed Kennell 46,465 #2 Posted Monday at 11:08 PM Install an electric fuel pump. 7 2 Share this post Link to post Share on other sites
TonyToro Jr. 2,503 #3 Posted Monday at 11:37 PM You should be able to find one no problem. Here’s a good one that’s my go to. https://www.amazon.com/Stens-520-570-Replaces-Ariens-23545-S/dp/B00ISW9J5E/ref=sr_1_1?crid=1BTP3SY9E9Q94&dib=eyJ2IjoiMSJ9.JxbtWebtA4TR7o9P8ug_51PekWkzAF4_IEQ79PHssZrQMiu-IH5bBxHXKpbf5oXIDUIYWSHR2gC_43A31C8d7VmjN1vW2Zghgw7C7Jcf2yi4Nb94MjhkuQhlYjuP7Fh0PuBenzvty-RQiH-GjIcCFLIt1SlvYt7U5TE9u-FZ3Y8ze0sWq_ZJFl2ym8KHUdK1K0fUxCeKcsKtR87iMEhvFyPfwanxTx3Gdzm_x3_TJlY.WJ4gxgHleXzAG5fLa6XJd-vF4ESbViKk9qZUEUJ5w7U&dib_tag=se&keywords=Stens+Kohler+k301+fuel+pump&qid=1783380946&sprefix=stens+kohler+k301+fuel+pump%2Caps%2C161&sr=8-1 1 Share this post Link to post Share on other sites
Handy Don 16,917 #4 Posted Tuesday at 12:31 AM (edited) 17 hours ago, FVan said: I have no gas being pumped by my Kohler K 103 fuel pump. I replaced the diaphragm, the holes in the new one didn't line up so I had to recut them and I had to also modify the stem. The new diaphragm did not resolve my issue and plus now it leaks gas. I cannot find an exact replacement one. Any suggestions would be appreciated. If you made the diaphragm taut across the body of the pump when you “recut” the holes, then you made it impossible for the mechanism to move the diaphragm up and down to pump fuel. Worse, if the mechanism pushes hard enough against the stretched diapharagm, it causes the rubber to split and gas flows into the oil sump. The holes were likely correct. Some aftermarket diaphragm’s stems are not cut precisely and do require minor adjustments. Correct install: FIRST, plate sand the faces of the body halves to be sure they are flat (the pump body flanges are fairly soft and can be warped by excessive tightening of the closure screws). Connect the diaphragm stem. Put the screws through the upper body, gently forcing the diaphragm onto the screws. Operate the actuator to its limit in one direction or the other to fully pull the diaphragm to its maximum travel. While keeping the actuator pulled, align the screws with the holes in the lower body and gradually tighten the screws sequentially across the body. The diaphragm edges will “scrunch” to make a good seal. DO NOT OVERTIGHTEN Edited Tuesday at 04:07 PM by Handy Don 3 Share this post Link to post Share on other sites
FVan 3 #5 Posted Tuesday at 03:13 PM Thank you for the suggestion, Ed. I try to keep things original, but it gets to a point where it's just not possible. Share this post Link to post Share on other sites
oldlineman 1,751 #6 Posted Tuesday at 03:56 PM plus peace of mind of not burning up a good engine because of gas in the oil pan. 1 Share this post Link to post Share on other sites
FVan 3 #7 Posted Thursday at 06:59 PM On 7/7/2026 at 8:13 AM, FVan said: Thank you for the suggestion, Ed. I try to keep things original, but it gets to a point where it's just not possible. On 7/6/2026 at 4:37 PM, TonyToro Jr. said: You should be able to find one no problem. Here’s a good one that’s my go to. https://www.amazon.com/Stens-520-570-Replaces-Ariens-23545-S/dp/B00ISW9J5E/ref=sr_1_1?crid=1BTP3SY9E9Q94&dib=eyJ2IjoiMSJ9.JxbtWebtA4TR7o9P8ug_51PekWkzAF4_IEQ79PHssZrQMiu-IH5bBxHXKpbf5oXIDUIYWSHR2gC_43A31C8d7VmjN1vW2Zghgw7C7Jcf2yi4Nb94MjhkuQhlYjuP7Fh0PuBenzvty-RQiH-GjIcCFLIt1SlvYt7U5TE9u-FZ3Y8ze0sWq_ZJFl2ym8KHUdK1K0fUxCeKcsKtR87iMEhvFyPfwanxTx3Gdzm_x3_TJlY.WJ4gxgHleXzAG5fLa6XJd-vF4ESbViKk9qZUEUJ5w7U&dib_tag=se&keywords=Stens+Kohler+k301+fuel+pump&qid=1783380946&sprefix=stens+kohler+k301+fuel+pump%2Caps%2C161&sr=8-1 Thank you Tony Toro and Handy Don. I did order a fuel pump just like the one in the picture. Funny thing is Amazon would not ship it to my PO Box or to my street address. You can't order directing from Sten so I ordered it from Zoro. I will also try the new diaphragm again and in stall like Handy Don suggested 1 Share this post Link to post Share on other sites
sqrlgtr 3,178 #8 Posted yesterday at 12:57 AM 5 hours ago, FVan said: I ordered it from Zoro. I have used them a few times and they have always been cheaper and recceived said items quicker than expected. Hope I didn't just jinx it for you/us. Share this post Link to post Share on other sites
Retired Wrencher 6,771 #9 Posted 10 hours ago On 7/6/2026 at 7:08 PM, Ed Kennell said: Install an electric fuel pump. I second that. Share this post Link to post Share on other sites
953 nut 67,240 #10 Posted 10 hours ago I am an advocate of using an electric fuel pump. This is a pump many of us use and like very well. They can be found on for about $ 25.00 1 1 Share this post Link to post Share on other sites
Ed Kennell 46,465 #11 Posted 9 hours ago 42 minutes ago, 953 nut said: This is the pump I have on all my tractors. 1 Share this post Link to post Share on other sites
sqrlgtr 3,178 #12 Posted 8 hours ago I have used both of these and prefer the all metal one because of the smaller physical size, not much but is smaller. Share this post Link to post Share on other sites
FVan 3 #13 Posted 5 hours ago Thank you all for the Feedback! If my Sten mechanical pump doesn't work out, I will cave and install one of the suggested Electric pumps. 1 Share this post Link to post Share on other sites
