Esbrian 16 #1 Posted September 2, 2021 After a dozen or so hours of starting and running beautifully, my new-to-me 312-8 ran for 30 seconds and then failed to restart this evening. I narrowed it down to a fuel delivery problem. Removed, disassembled, and reassembled the fuel pump, finding no obvious (to me) problems. It still wouldnt start. I read a thread on this forum recommending pointing the nose downhill, and after a minute or so parked nose-down, was able to start and finish my mowing for the night. Do i need a new fuel pump? When it wouldnt start, i disconnected the line to the carb at the discharge of the fuel pump and turned it over for a few seconds, no gasoline spatter from the discharge port... Share this post Link to post Share on other sites
dcrage 628 #2 Posted September 2, 2021 One thing that might help is to close the fuel valve at the base of the gas tank each time you stop your tractor. Doing that allows me to start my 310-8 for at least a week. Longer than that I have to pour a little gas thru the spark plug socket to get the engine to start. I obviously have a leak back from my fuel pump. And a new fuel pump would probably fix your problems. 1 Share this post Link to post Share on other sites
lynnmor 7,306 #3 Posted September 2, 2021 Check the entire fuel lines from the screen in the tank to the carburetor. If there is any restriction or air leaks, the pump may not pull it. 3 Share this post Link to post Share on other sites
skrusins 128 #4 Posted September 2, 2021 Did you take the gas line off the carb and crank the motor to see if you get a steady flow. I did install a electric fuel pump with a off and on switch. I always turn on the fuel pump to get started and shut off after it starts. 2 Share this post Link to post Share on other sites
Esbrian 16 #5 Posted September 2, 2021 6 minutes ago, lynnmor said: Check the entire fuel lines from the screen in the tank to the carburetor. If there is any restriction or air leaks, the pump may not pull it. I dont think there are restrictions, as gas flowed freely from the fuel pump suction line when i brought it below tank level... how would i check for air leaks? Share this post Link to post Share on other sites
Esbrian 16 #6 Posted September 2, 2021 4 minutes ago, skrusins said: Did you take the gas line off the carb and crank the motor to see if you get a steady flow. I did install a electric fuel pump with a off and on switch. I always turn on the fuel pump to get started and shut off after it starts. With the gas line to the carb removed at the fuel pump, i had no apparent flow from the pump after cranking for several seconds. Verified only by lack of gas splashed on the front of the engine AFTER cranking. Share this post Link to post Share on other sites
lynnmor 7,306 #7 Posted September 2, 2021 Just now, Esbrian said: I dont think there are restrictions, as gas flowed freely from the fuel pump suction line when i brought it below tank level... how would i check for air leaks? If the hose to the tank has cracks or a poor seal at each end, then air can be sucked in by the pump. Usually, but not always, fuel will leak at those places. Share this post Link to post Share on other sites
SylvanLakeWH 25,558 #8 Posted September 2, 2021 I put an in line marine bubble and it works like a charm… couple squeezes and she fires right up… 2 Share this post Link to post Share on other sites
Esbrian 16 #9 Posted September 2, 2021 (edited) 27 minutes ago, SylvanLakeWH said: I put an in line marine bubble and it works like a charm… couple squeezes and she fires right up… Glad to see im not alone with this issue! Was pretty pissed when it started, as I'd finally gotten my deck to behave after 2 weeks of drama, but it was pretty gratifying to get it running again Edited September 2, 2021 by Esbrian 2 Share this post Link to post Share on other sites
oliver2-44 9,750 #10 Posted September 2, 2021 55 minutes ago, Esbrian said: , my new-to-me 312-8 Most of my tractors have been sitting or are tired when I get them. Early on in their resurrections I do a tank cleaning and then a new fuel line, fuel filter, tank shutoff and tank grommet. Since its a new to you horse, this may be a good place to start. Many on here like the clear blue tubing you can see the gas in. With the tank up high, under the seat a hand squeeze primer bulb or an electric fuel pump may be in order. i have a C81 with the tank under the seat, if i don't run it every 2-3 weeks, it needs a prime, then runs good. 2 1 Share this post Link to post Share on other sites
kpinnc 12,049 #11 Posted September 2, 2021 (edited) 8 hours ago, SylvanLakeWH said: I put an in line marine bubble and it works like a charm… couple squeezes and she fires right up… I've used these for my tractors that have the fuel tank under the seat for years. Best cheap fix for saving batteries and starters. Otherwise you can kill the battery before the onboard fuel pump can refill the carb. No question that keeping good fuel lines is a good thing, but you will never find all the places in the fuel path that allows some air into the system. Edited September 2, 2021 by kpinnc 1 Share this post Link to post Share on other sites
richmondred01 2,237 #12 Posted September 2, 2021 Cheap easy fix to replace the lines, filter and fuel pump. 20 minute job. Cost about 30 bucks if you use the knock off replacement pump. 1 Share this post Link to post Share on other sites
