handyrandy 7 #1 Posted March 21, 2020 I think the fuel somehow disappears from around the carburetor when it sits for some time. After I crank it for 10-15-20 seconds the fuel pump pumps the fuel back into the system and it starts right up and restarts right up. But after sitting a few weeks it takes a while to get it started again. If I take the spark plug out and put a little gas in the spark plug hole it fires right up. Thanks! Share this post Link to post Share on other sites
pfrederi 17,125 #2 Posted March 21, 2020 Very common with under seat gas tanks. You can get a squeeze bulb primer or like may of us get an electric fuel pump. Share this post Link to post Share on other sites
peter lena 8,035 #3 Posted March 21, 2020 you can use a squeeze bulb or install one of these ,http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve-8mm-barbed--p-9581.html?gclid=Cj0KCQjw9tbzBRDVARIsAMBplx8dz3KII-59oVTCa8w6VPvPj3R8q5H202WQrMicZEjKHgJvwl5zgwcaArK5EALw_wcB have one on each of my 12 magnums , got them on line for cheap, and definitely help on instant starting. just my own experience, pete 1 Share this post Link to post Share on other sites
handyrandy 7 #4 Posted March 21, 2020 Check valve works for me. Thanks for the help! Share this post Link to post Share on other sites
clueless 2,898 #5 Posted March 21, 2020 SOP for the rear tank with the mechanical fuel pump. I put a marine squeeze bulb on mine under the seat, just lift the seat a couple of good squeezes and she fires right up. About an $8.00 fix. 3 Share this post Link to post Share on other sites
handyrandy 7 #6 Posted March 21, 2020 1 hour ago, clueless said: SOP for the rear tank with the mechanical fuel pump. I put a marine squeeze bulb on mine under the seat, just lift the seat a couple of good squeezes and she fires right up. About an $8.00 fix. This bulb looks like what I need? So just run the fuel line up to the top of the tank were it is easy to get to the bulb, install the bulb and run the fuel line on to the fuel bump? Share this post Link to post Share on other sites
JoeM 7,608 #7 Posted March 21, 2020 something that worked on a machine that gave me the same trouble was routing the fuel line up high on the battery side of the engine then dipping back under the motor to the carb. Made like a hump or trap in the fuel line to limit back drain. I put the fuel filter there easy to change also. 4 Share this post Link to post Share on other sites
clueless 2,898 #8 Posted March 21, 2020 14 minutes ago, handyrandy said: This bulb looks like what I need? So just run the fuel line up to the top of the tank were it is easy to get to the bulb, install the bulb and run the fuel line on to the fuel bump? That's it lift the seat up, the big hole in the seat pan reach in and cut about 7 or 8 inches off the fuel line, make sure you turn off the gas first. Couple of clamps, make sure the arrow is pointing toward the engine, zip tie the line in a couple of places for stability, done, cheap and easy. The bulb has check valves so it take awhile before it losses its prime. 1 Share this post Link to post Share on other sites
tom2p 2,393 #9 Posted March 22, 2020 12 hours ago, handyrandy said: I think the fuel somehow disappears from around the carburetor when it sits for some time. After I crank it for 10-15-20 seconds the fuel pump pumps the fuel back into the system and it starts right up and restarts right up. But after sitting a few weeks it takes a while to get it started again. If I take the spark plug out and put a little gas in the spark plug hole it fires right up. Thanks! I don't believe this is a problem - not for me at least ??? our tractors including 312-8 and 416-H have done this the entire time we've owned them if they sit for weeks / over a month / whatever - will need to crank a little longer before they start and maybe it's not only not a bad thing ... ??? ... during cranking might get oil to the areas that don't have an appreciable amount of oil after sitting for a prolonged period (before the engine begins to run at higher rpm) ??? 1 Share this post Link to post Share on other sites
pfrederi 17,125 #10 Posted March 22, 2020 10 hours ago, tom2p said: I don't believe this is a problem - not for me at least ??? our tractors including 312-8 and 416-H have done this the entire time we've owned them if they sit for weeks / over a month / whatever - will need to crank a little longer before they start and maybe it's not only not a bad thing ... ??? ... during cranking might get oil to the areas that don't have an appreciable amount of oil after sitting for a prolonged period (before the engine begins to run at higher rpm) ??? Maybe not for you but When you go to start your under seat tank WH snow plow/blower and it has sat for a week or two and it is in the teens you wonder if the battery will hold up long enough to get her started 2 Share this post Link to post Share on other sites
lynnmor 6,762 #11 Posted March 22, 2020 12 hours ago, tom2p said: if they sit for weeks / over a month / whatever - will need to crank a little longer before they start and maybe it's not only not a bad thing ... ??? ... during cranking might get oil to the areas that don't have an appreciable amount of oil after sitting for a prolonged period (before the engine begins to run at higher rpm) That is a valid point, but the downside is the wear on the starter and discharge of a marginal battery. I guess it is a pick your poison thing. One could crank a bit without choke or throttle if an engine has been sitting for a long time. 1 Share this post Link to post Share on other sites
handyrandy 7 #12 Posted March 22, 2020 13 hours ago, tom2p said: I don't believe this is a problem - not for me at least ??? our tractors including 312-8 and 416-H have done this the entire time we've owned them if they sit for weeks / over a month / whatever - will need to crank a little longer before they start and maybe it's not only not a bad thing ... ??? ... during cranking might get oil to the areas that don't have an appreciable amount of oil after sitting for a prolonged period (before the engine begins to run at higher rpm) ??? I do understand that, but it is taking entirely too long to start and I am going to wear out the starter. My other 312 does not have this issue and I have been using the same tractor for 30 years that I bought new. It has always started easily. Share this post Link to post Share on other sites
pfrederi 17,125 #13 Posted March 22, 2020 I have a 310-8 with under seat tank an C-81 with a Magnum 12 . Both start fairly quickly but my 418a C-175s, C141 not so they have been converted to electric. 1 Share this post Link to post Share on other sites
tom2p 2,393 #14 Posted March 24, 2020 On 3/22/2020 at 11:05 AM, lynnmor said: That is a valid point, but the downside is the wear on the starter and discharge of a marginal battery. I guess it is a pick your poison thing. One could crank a bit without choke or throttle if an engine has been sitting for a long time. I do just that - crank without choke do this for a bit - and then use as little choke as possible to get the engine to fire not a surprise - I place a premium on quality batteries prob jinx myself by stating this - but never had an issue with a starter ... ever ... includes two tractors (312-8 and one 416-H) I've owned since late 90's / early 2000's 1 Share this post Link to post Share on other sites
Reel Mower Freak 125 #15 Posted March 26, 2020 I went with an electric fuel pump on my 520 and it worked very well to cure this issue. I’m going to try the marine prime bulb on my 314 as it isn’t nearly as bad as the 520 for losing prime. 1 Share this post Link to post Share on other sites
handyrandy 7 #16 Posted December 11, 2020 I finally found the problem with the fuel. Some past owner had tied the fuel line up to the top of the frame creating a big hump in the fuel line. I was pressure washing the frame out and took the plate off with the slots for the gear shift and noticed it. I dropped the fuel line back down to the bottom of the frame and the problem went away. 1 Share this post Link to post Share on other sites
bds1984 1,382 #17 Posted December 12, 2020 I recently acquired a C175 that the previous owner said would start hard from the fuel draining back. Instead of a primer bulb he installed a schrader valve in the gas cap to allow a bike pump to pressurize the fuel tank enough to push fuel up to the engine. Anyways, don't forget to check the fuel lines for dry rot and cracks. I've acquired a few machines over the years from previous owners who claimed hard starting when the problem was traced to old/cracked fuel lines. Share this post Link to post Share on other sites
tom2p 2,393 #18 Posted December 12, 2020 2 hours ago, bds1984 said: I recently acquired a C175 that the previous owner said would start hard from the fuel draining back. Instead of a primer bulb he installed a schrader valve in the gas cap to allow a bike pump to pressurize the fuel tank enough to push fuel up to the engine. Anyways, don't forget to check the fuel lines for dry rot and cracks. I've acquired a few machines over the years from previous owners who claimed hard starting when the problem was traced to old/cracked fuel lines. when were kids we did something similar - but used our lungs we would sometimes blow through the gas cap vent hole ... yep - place lips down on the cap and blow worked well Share this post Link to post Share on other sites
