# b&s carb issues... no gas.



## jmbetker002 (Apr 22, 2011)

I just a moter swap in my riding lawn mower and I don't know if I have all the wires exactly right or not. The engine will run but only with fuel dumped down the carb. What is the wire for that comes out the bottom of the carb? I went from a 1994 15hp to a 1995 14.5hp so everything is close wire wise... but not a plug in swap by any means. Any info you got will help.


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF :wave:

Sounds like you are talking about the fuel shut off "valve". You need it.

What is the model number on the engine?

BG


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## jmbetker002 (Apr 22, 2011)

Basementgeek said:


> Hi and welcome to TSF :wave:
> 
> Sounds like you are talking about the fuel shut off "valve". You need it.
> 
> ...


The model number of the original engine is 280777.

The model number of the new one is 287707.

Differences I notice between the two are;

- an extra wire coming from behind the flywheel of the new one.
- no fuel pump for the new one. Old one had one and a acumen line on the block for it. The line is feeding gas to the carb by gravity now and feeding the bowl.

Other then that some of the wires are different colors. The main thing now is why is it not pumping fuel and what do the two wires coming from the flywheel do... or go to!!!


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## jmbetker002 (Apr 22, 2011)

jmbetker002 said:


> The model number of the original engine is 280777.
> 
> The model number of the new one is 287707.
> 
> ...


The moter starts with the key. It shuts down with the key. I don't know if the headlights work because they are missing from the mower. The carb has been pulled and cleaned to the best of my abilities... I'm not very good with lawnmower style moters but i know snowmobiles very well. I can't think of anything else to ad now. I can post pics if it helps anyone help me but you have to tell me what you need to see.

Thanks for helping.
Josh


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## jrrdw (Jun 26, 2010)

Use a 12 volt test light and find a wire coming from the key switch that has power when the key is on and no power when the key is off. That wire coming from the bowl/bottom of the carburator is the "Anti backfire solenoid". Hook up that wire to the switched wire coming from the key switch and it should run, (if everything else is right).

The wires coming from behind the flywheel are the alternator wires. Sounds like they are 2 different charging systems. You might be able to switch the alternators so that you don't have to change it around on the tractor, if they have the same mounts, clearance etc...


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## jmbetker002 (Apr 22, 2011)

jrrdw said:


> Use a 12 volt test light and find a wire coming from the key switch that has power when the key is on and no power when the key is off. That wire coming from the bowl/bottom of the carburator is the "Anti backfire solenoid". Hook up that wire to the switched wire coming from the key switch and it should run, (if everything else is right).
> 
> The wires coming from behind the flywheel are the alternator wires. Sounds like they are 2 different charging systems. You might be able to switch the alternators so that you don't have to change it around on the tractor, if they have the same mounts, clearance etc...


I just looked at the charging systems. They won't interchange between the two moter. The flywheels are different. Any pointers on hooking up the charging system now?


Josh


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## jrrdw (Jun 26, 2010)

Wow that's kinda a tough one. The simple way would be to put a "float charger" on it. That way the battery will be ready to go when you need it to start or you can talk to your local dealer to get the parts and build a charging system.

Do you have the tractor the replacment engine came off of?


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## Basementgeek (Feb 7, 2005)

My guess would be three wires. One is for kill circuit, one is DC for the charging system.
Third one about 14 volts AC to run the lights. You will need a DVOM to find which one AC and which one is DC.

BG


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## CN_Rail (Apr 18, 2011)

Well that's odd. Does it have a fuel shut-off valve on the fuel line? If so turn it on.


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## Basementgeek (Feb 7, 2005)

It is not going to run until the Anti backfire solenoid is hooked up as it shuts off the gas.

BG


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## jmbetker002 (Apr 22, 2011)

Basementgeek said:


> My guess would be three wires. One is for kill circuit, one is DC for the charging system.
> Third one about 14 volts AC to run the lights. You will need a DVOM to find which one AC and which one is DC.
> 
> BG


Now I'm getting somewhere. I will look into this for sure.


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## jmbetker002 (Apr 22, 2011)

jrrdw said:


> Wow that's kinda a tough one. The simple way would be to put a "float charger" on it. That way the battery will be ready to go when you need it to start or you can talk to your local dealer to get the parts and build a charging system.
> 
> Do you have the tractor the replacment engine came off of?


I don't have the donor tractor. I wish I did ... then I could just swap wire harnesses.


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## jmbetker002 (Apr 22, 2011)

Basementgeek said:


> It is not going to run until the Anti backfire solenoid is hooked up as it shuts off the gas.
> 
> BG


Your on to something here maybe. I thought I hooked up this wire the same as the old moter. Both engines have. I will check it though.


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## mikeinri (Dec 2, 2009)

That wire is 100 percent the reason it's not running. Well, not exactly, there may be other issues, but it definitely won't run without that carb wire.
Ignore all the other wires for now, a wiring diagram from B/S would also help, you can contact them through their website (you may need to buy a service manual, which is worth having anyway).
Hope this helps.
Mike


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## K-B (Oct 24, 2005)

If the fuel solenoid is working, there will be an audible click when you toggle the ignition on/off.


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## k2skier (Sep 30, 2008)

If you just want to see if it will run at first, go get a 495933 at our local shop, it's a float bowl kit with a standard bowl nut. You can then run the engine without a battery. I dont know the number for a standard nut to replace the AF solenoid, thats an option also. Just make sure and lower the RPM's to an idle if you shut it off when it's more than warm.


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## jmbetker002 (Apr 22, 2011)

k2skier said:


> If you just want to see if it will run at first, go get a 495933 at our local shop, it's a float bowl kit with a standard bowl nut. You can then run the engine without a battery. I dont know the number for a standard nut to replace the AF solenoid, thats an option also. Just make sure and lower the RPM's to an idle if you shut it off when it's more than warm.


Hooked the wire from the carb right to the battery... fired right up. Heard the click just like it was said in prior post. Now... to figure out the charging system. No idea how this is going to work.... two wires on new... one wire on old. Can it just be hooked right to the battery? Anyone know?


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## jrrdw (Jun 26, 2010)

What make and model is the tractor, (all the ID numbers) and what is the full ID numbers on the replacement engine?

Is there a diode in 1 of the wires coming from the alternator? What color are the wires and plug coming from the alternator (color will ID the alternator).

At this point you need to know if you have a internal voltage regulator or a external regulator.


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## jmbetker002 (Apr 22, 2011)

jrrdw said:


> What make and model is the tractor, (all the ID numbers) and what is the full ID numbers on the replacement engine?
> 
> Is there a diode in 1 of the wires coming from the alternator? What color are the wires and plug coming from the alternator (color will ID the alternator).
> 
> At this point you need to know if you have a internal voltage regulator or a external regulator.


Color is black and red. Diode... don't know... looks like just 2 wires from what I can see. The new moter has an internal... old was external. I will get the numbers when I get home from work.


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