illinilefttackle 399 #1 Posted May 29, 2018 Hi Guys- I have finally decided to replace the manual fuel pump on my C-125A- I'm sure I can figure it out- but I thought I would ask those of you that have done it- if you have any help or hints? K-301 does not have pressurized oil system, so I cant tap into that for safety kill switch- Maybe alternator? Thanks for any help- My eyes aren't what they used to be, when I was "chasing down Quarterbacks".- Al Share this post Link to post Share on other sites
JoeM 7,620 #2 Posted May 29, 2018 I just installed one on a 312-8 and wired into the accessory terminal on the ignition switch. 3 Share this post Link to post Share on other sites
illinilefttackle 399 #3 Posted May 29, 2018 Thanks- I will have to look on my wiring diagram to see where that is on mine- they are different- Al Share this post Link to post Share on other sites
Jerry77 1,218 #4 Posted May 30, 2018 31 minutes ago, OILUJ52 said: wired into the accessory terminal on the ignition switch with an in-line fuse and a shut off switch for when you want the power on and the pump not running... Share this post Link to post Share on other sites
illinilefttackle 399 #5 Posted May 30, 2018 Thanks Jerry- sounds good- my main concern is to not draw too much amperage from the circuit I tap into-to hurt performance- Al Share this post Link to post Share on other sites
Jerry77 1,218 #6 Posted May 30, 2018 44 minutes ago, illinilefttackle said: not draw too much amperage I don't remember the amp draw on mine, but you want to keep the psi output of the pump below 3 psi...I think mine is 1.5 to 2.5 psi..works perfect... 1 Share this post Link to post Share on other sites
JoeM 7,620 #7 Posted May 30, 2018 I used a Mr Gasket Part No. 42S Specs: 2-3.5 PSI, 28 GPH. The current draw is one amp. 2 Share this post Link to post Share on other sites
midpack 804 #8 Posted May 30, 2018 You want to use a relay to power the pump directly from the battery (fused) I used the light switch wiring to activate the relay, it's only "on" when the key is in either start or run 2 Share this post Link to post Share on other sites
953 nut 51,628 #9 Posted May 30, 2018 The lighting circuit is already fuse protected and ate amperage for a low pressure electric fuel pump is next to nothing. Just connect the wire for the pump to the incoming (hot with the key on) side of your light switch. Be sure to mount the fuel pump low on the frame because they are great pushers but not too good at drawing a suction. 5 Share this post Link to post Share on other sites
pfrederi 17,143 #10 Posted May 30, 2018 2 hours ago, 953 nut said: The lighting circuit is already fuse protected and ate amperage for a low pressure electric fuel pump is next to nothing. Just connect the wire for the pump to the incoming (hot with the key on) side of your light switch. Be sure to mount the fuel pump low on the frame because they are great pushers but not too good at drawing a suction. Adding a relay is unnecessary and just one more part and a couple of connections to fail at some point later in life. 3 Share this post Link to post Share on other sites
midpack 804 #11 Posted May 30, 2018 32 minutes ago, pfrederi said: Adding a relay is unnecessary and just one more part and a couple of connections to fail at some point later in life. I'd rather that than run extra power through the key switch, but hey... everyone makes choices... Share this post Link to post Share on other sites
illinilefttackle 399 #12 Posted May 30, 2018 Thanks Guys for all the suggestions- I've been wanting to do this conversion for years- the Horse just decided now was the time!- Al 1 Share this post Link to post Share on other sites
illinilefttackle 399 #13 Posted June 3, 2018 Just as an update- I used a pump from Edelbrock, low pes.,and tapped into light circuit ahead of light fuse. I fused the pump at 5 amp per directions. This tractor then started before it turned over one revolution- it has never started that quickly before. Engine sounded smoother also- I'm a happy guy!- Thanks- Al 1 1 Share this post Link to post Share on other sites
illinilefttackle 399 #14 Posted June 5, 2018 Hate to rain on my om parade- but- its not working out well. I put a regulator on it to stop it flooding engine at lower speeds. That worked, but when I turn it down to stop flooding- it doesn't supply enough gas for high speed. Return line? Or what? Al 1 Share this post Link to post Share on other sites
pfrederi 17,143 #15 Posted June 5, 2018 (edited) What is pressure rating of your new pump?? Is your carb float OK Not filled with gas??) I have put electric pumps of various brands up to 4 psi on 5 horses no problems yet. Edited June 5, 2018 by pfrederi 2 Share this post Link to post Share on other sites
953 nut 51,628 #16 Posted June 6, 2018 2 hours ago, illinilefttackle said: stop it flooding engine at lower speeds. You need to replace the needle and seat in your carburetor, like Paul said there shouldn't be any problem even at 5 PSI if the carburetor is good. Share this post Link to post Share on other sites
illinilefttackle 399 #17 Posted June 6, 2018 1 hour ago, pfrederi said: What is pressure rating of your new pump?? Is your carb float OK Not filled with gas??) I have put electric pumps of various brands up to 4 psi on 5 horses no problems yet. My pump is 2-5PSI- I dont know the condition of the float- carb is older- I wonder if because old pump was getting weaker & weaker it hid the bad float? Looks like a carb teardown is in order- Thanks for the headsup!- Al Share this post Link to post Share on other sites
953 nut 51,628 #18 Posted June 6, 2018 9 hours ago, illinilefttackle said: wonder if because old pump was getting weaker & weaker it hid the bad float? The mechanical pump delivers fuel in direct relationship to the engine speed. An electric pump is constant. The needle and seat are your problem. Share this post Link to post Share on other sites
illinilefttackle 399 #19 Posted June 6, 2018 Thanks for your comments- the throttle shaft on my carb was badly worn- just put up with it until now- combination of needle & seat plus throttle shaft led me to order a new Kohler carb on line-I will let you know what happens- can't wait!- Thanks- Al 1 Share this post Link to post Share on other sites
illinilefttackle 399 #20 Posted June 10, 2018 Hi Guys- Well- I'm sure each one of you have been in the "place" I am right now. You attack a problem systematically & logically & it still doesn't work. I just went back over everything I did to make sure I didn't make any foolish mistakes. Still the same result- engine starts &runs well, but when you slow it down the carb starts leaking out gas and engine chokes out. I'm beginning to think the problem lies in my fuel pump choice. I was looking for a square shaped "Facet" pump that I was familiar with, but they only had a robust looking Edelbrock pump- 2-3.5 PSI- 28GpH. I would like to keep electric pump setup- but need tractor running- What do you guys think? Should I try to install a return fuel line to the tank-OR- install a rpm regulated stock fuel pump? Thanks- Al Share this post Link to post Share on other sites
pfrederi 17,143 #21 Posted June 10, 2018 Did you get the new carb? If the float and needle valve are ok they will limit the fuel flow no matter what Assuming pump is at it rated PSI (less than 4psi) . Did you double check the float settings...11/64 and 1-1/32 drop??? as i said I have a few Facet pumps at 4 psi and no issues... 1 Share this post Link to post Share on other sites
illinilefttackle 399 #22 Posted June 10, 2018 Sorry- left out that I did get the new carb- checked it out , double checked the float levels- Engine won,t start at any pressure lower than 4 Lbs. At 4 1/2 it starts & runs perfect until you slow it down to around 900 rpm or so- then fuel starts coming out and engine floods out. I'm not a novice- but I feel out of ideas- Thanks- Al Share this post Link to post Share on other sites
illinilefttackle 399 #23 Posted June 10, 2018 Engine won't start at 4 Lbs- but will start @ 4 1/2 Lbs. But then floods out.- Al Share this post Link to post Share on other sites
illinilefttackle 399 #24 Posted June 10, 2018 Just to test, I should be able to turn key on @ 4 lbs and let the pump run- and nothing should leak- correct? I have a Nelson muffler right in front of carb- and dont want to start a fire- Al Share this post Link to post Share on other sites
pfrederi 17,143 #25 Posted June 11, 2018 You said the edelbrock pump was rated at 2 - 3.5 psi. How are you getting 4.5??? Yes turn the key on and leave it there should be no leakage. My pumps change sound when the float valve closes and pressure builds.... New carb or not it comes back to the float and needle valve that control the fuel going in. 1 1 Share this post Link to post Share on other sites