Fuel issue 312-8

[JoCarter 24]

So I am having a issue with my 312-8 K Magnum 12 engine not getting fuel to the it.

1. Replaced spark plug, Fuel valve at tank bottom has flow when opened

2. replaced fuel filter and get fuel all the way to fuel pump connection when vacuum created on line.

3.took off fuel pump and cleaned out, may need to replace it since some build up on diaphragm.

4.took carb off and its bone dry.

 

This engine has ran in the past and still cranks but one turn over, is this a carb issue or a fuel pump issue, has anyone ran into this before.

 

thanks

[Bill D 1,597]

Change the fuel pump.  Use a OEM pump or electric.  The cheap eBay pumps have been known to ruin an engine by leaking gas into the crankcase and diluting the oil.  You can also retrofit a vacuum pulse pump onto the engine by replacing the pump you have with a blank off plate that has a 1/4 hose barb on it .  Again use an OEM pump.  The vacuum pulse pumps are cheaper than the original style pump or electric pump.  Good luck with it.  Bill

[gwest_ca-(File Mod) 10,490]

Has this engine been sitting idle for an extended period?

The float needle in the carb can stick to the seat and not allow any fuel in. They added a spring to the needle so when the float dropped it would lift the needle off it's seat. I don't know how effective that was.

 

Garry

[953 nut 51,625]

7 hours ago, JoCarter said:

some build up on diaphragm.

The build-up you have is also present in the two valves of the fuel pump. Your pump has an inlet valve, a diaphragm and an outlet valve. The movement of the  diaphragm will pull fuel from the tank on the down stroke and push it to the carburetor on the up stroke. If the valves don't seal properly it can't pump. 

If you have been running gas with ethanol the deposits are probably from that, use this site to locate a station that sells ethanol free gas.https://www.pure-gas.org/

[The Tuul Crib 7,332]

Stay away from the fuel pumps from 

china! I went to electric fuel pump

with great results!

[FBaggshorses 3]

Hello, I'm new to this site and greatly appreciate all the input and knowledge that's given so freely.

I have recently had a starting issue with my C-120. I've pulled the gas line that comes from my fuel pump to the carb and I gave no gas coming from the pump which tells me the fuel pump is shot. I'm almost certain is a Japanese knock off pump.

I want to convert to an electric pump and would appreciate some how tools as to the proper way to accomplish this. I've already purchased a Facet electric pump that pushes 2-5 psi and was wondering if I also need to run an inline gas regulator with the pump?

Any info on electric fuel pump conversion would be appreciated! 

[Tuneup 1,416]

Interesting. The 120's tank is above the carb bowl so an electric pump shouldn't be needed. Maybe a rubber squeeze pump would give you the prime you need. The pump on the engine is normally weak so the owners of the 80+ machines with under seat tanks have issues like the original poster.

I can't say that your carb can resist 5 psi so hopefully someone else will be by with some info for you.

[pfrederi 17,143]

I haven't had any problems with a 4 psi Facet pump.  I would try yours if it floods then add regulator.

[FBaggshorses 3]

cfWell hey thanks Tuneup,

I certainly appreciate your advice.

Although, as stated, i pulled the gas line from the carb and while turning the engine over got no gas whatsoever coming out of the line from the pump. Thats always been my  way of testing a fuel pump as to whether its good or bad.

Not quite understanding  how a rubber squeeze pump might make a difference. I've just read alot about how these knockoff pumps are prone to failure and also how much better these engines start and run with an electric pump.

Again your input is greatly appreciated

[FBaggshorses 3]

Hey thanks Pfrederi that sounds like a good idea. Ive already purchased the Facet 4-7 psi posi-flow electric pump from Pegasus Racing and just waiting for it to arrive. Hopefully I won't need to purchase a regulator but have that  Auto zone sells them.

Thank you much!

Edited June 9, 2020 by FBaggshorses

[FBaggshorses 3]

Was just wondering where you ran you positive hot lead for the electric pump . Ive read where one guy ran his to his light switch but then you'd loose your lights. I don't really want to do that and that an inline fuse must also be run.

Just curious as to how you ran yours.

Again , thanks so much for your input

[tunahead72 2,337]

1 hour ago, FBaggshorses said:

... i pulled the gas line from the carb and while turning the engine over got no gas whatsoever coming out of the line from the pump. Thats always been my  way of testing a fuel pump as to whether its good or bad...

 

Have you checked any part of your fuel supply system BEFORE the fuel pump?  So, tank, shutoff, fuel line, filter...?

[FBaggshorses 3]

Actually no I haven't checked the valve under the tank nor the fuel filter but I did pull the line going to the fuel pump and had gas Tunahead72

[bottjernat1 2,189]

[peter lena 8,050]

jocarter, recently did this, on my c85/magnum swap , going to a UNISTRUT bolt on brace is the way to go for total silence of electric pump operation. that 5/16 " angle brace is bombproof , used an existing frame hole on rear of engine corner area, combined that with electrical pump wiring on this site . unistrut makes many corner braces, the type i used is the last picture , sitting on top of engine. trying to find a solid noise reducing area , was difficult , the bolt on bracket , eliminates the noise, pete

 

[FBaggshorses 3]

Thanks bottjernat1 appreciate the info however I'm not interested in another knockoff fuel pump.

I'd spend the $ on the original oem kohler before buying another that won't last...but thank you

[bottjernat1 2,189]

4 minutes ago, FBaggshorses said:

Thanks bottjernat1 appreciate the info however I'm not interested in another knockoff fuel pump.

I'd spend the $ on the original oem kohler before buying another that won't last...but thank you

Im sorry about your luck with the knock offs i have never had an issue yet with them i buy them all the time. i also have a few genuine kohler ones. Last year i had one original one fail for a customer i ended up putting a knock off one on they are still running the machine. Everything has its good and bad side. just like a new car even they fail

Edited June 9, 2020 by bottjernat1

[FBaggshorses 3]

Hmmm....thats interesting.

Well maybe ill have to reconsider if replacing one on one of my other horses ..thank you

[FBaggshorses 3]

Very good info Peter lena and thank you. This info should help me out immensely.  So appreciative of all the great responces on this wheel horse site. Thank you so much 

[cgambino1018 21]

newbie here,

have a 1988-90 312-8 that sat for 2 years.  tried to start it today.. while spraying starter fluid it would run.  once i stopped the stream it would die.  i got gas going to the gas pump pump but not out the other end.  i took the pump off and this is what i have (see pics).

what are my options?  do i just order a new pump or try to fix this.  seems like the  gasket is torn.  

all help is appreciated. 

Chris from CT.