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Another B&S 18 hp twin not getting fuel


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08-10-09, 11:53 AM   #1  
Another B&S 18 hp twin not getting fuel

I have an old Signature 2000 series mower. When I got it out this year to mow, it would not run well. I cleaned the fuel tank and blew out the lines. It seemed to run fine then with a slight choke. When I used up the gas and refilled, it would only run with a full choke and then didn't have enough power to mow. This was fresh gas and worked fine in my weed whacker. Rechecked fuel lines which were OK and flowed freely to the pump. I pulled off the 3-bolt pump and it looked OK, but I went ahead and put in a kit. When I put it back together it still wouldnt run and I got a lot of gas going out the bottom of the pump to the crankcase, so I took it back apart and reinstalled tightening the bolts very tight. Now no gas out the bottom, but the unit won't run even fully choked. It does run when primed though. not sure what to check or try next - help!

 
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08-10-09, 01:00 PM   #2  
I hope your weed wacker is a 4-cycle. I would say you need to clean the carb.

 
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08-10-09, 01:16 PM   #3  
Thanks. is there a cleaning spray or Will the carb need to be removed and disassembled? (I haven't done this before.) Also, is there a way to check the pump to see if I have botched the reassenmly? Will gas getting in the bottom hose have hurt anything?

 
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08-11-09, 03:10 PM   #4  
BTW, the model is: 422707 Type: 1510 01 Code: 91041912

(Weeder is 4-cycle)

 
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08-13-09, 01:06 AM   #5  
You could look up the pump assembly to verify you have it together right. Is fuel getting into the bowl of the carb? If not, the pump is not right. You shouldn't have to make the bolts "very tight" to make it work.


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08-13-09, 12:30 PM   #6  
Yes, I used the diagram but I did it while the carb was on the engine - from the side, so it was a little tricky. I will check to see if gas in bowl. I just wondering if gas in the vacuum line will cause any problems?

 
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08-13-09, 03:18 PM   #7  
Well, the fuel bowl was dry and had a little sand in the bottom. I wiped it out andI filled it and put the carb top back on. It ran for awhile and started blowing out black colored gasokine out the vacuum hose (not the one to the fuel pump).
So it seems the pump isn't working right. I guess I will remove the carb so I can tell more what I'm doing, although I though I had it back together correctly?(I am near 70 yrs old and don't see that well) The carb appears to need cleaning as well. I don't have an air gun, will can spray work and should the carb be soaked?

 
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08-14-09, 09:57 PM   #8  
Did you lose the tiny springs in the fuel pump? They are very small and hard to see. If you ever drop one, it vanishes.


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08-15-09, 09:20 AM   #9  
Yes, I had to buy a pump kit to get the spring. The assembly diagram doesn't really show how these tiny springs fit. It appears that with the pump removed and looking at the carb from the front, one goes on a cylinder-like extrusion on the lower left. Then the diaphram goes on, and then the other tiny spring goes on a similar extrusion in the pump body.

I did remove the carb and cleaned with spray from both sides of all orifices. It wasn't really very dirty though. Reassembled the carb and pump very carefully. I then blew on the pump inputs, the fuel line input was clear, and the vacuum input showed resistance and I could hear the diaphram working. I reinstalled it, but the engine still wouldn't run w/o priming. It was getting dark and battery was down so I quit for the day.
I'm going to recharge batt and check the vavuum line this morning to see if it is pulsing. Also gas line to make sure its passing gas. Then if OK, I will check fuel bowl and if it is dry, I don't know what else to try. ???

 
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08-15-09, 07:30 PM   #10  
Sounds like it should be working. Will fuel flow freely from the tank to the pump?


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08-16-09, 09:44 AM   #11  
Well its running OK now. At first it blew white smoke like crazy out the muffler and then some blackish gas out the vacuum vent, several ounces. All that has cleared now. I guess this was the fuel that went down the vacuum hose the first time I "fixed" the pump.

This thing seems to have an automatic throttle? The throttle control does work to speed up or down the engine to a degree, however if I manually move it on the carb it really revs up. Is this normal operation?

 
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08-16-09, 07:28 PM   #12  
You're saying it revs up to a normal high speed by using the throttle control, but if you reach down at the carb and manually turn the throttle shaft on the carb, it revs higher than normal, then yes, that would be normal. Don't make a habit of overspeeding the engine though, it can come apart.


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08-21-09, 04:59 PM   #13  
Well I'm back to square one! It ran great for 1 day and I got a lot of mowing done. The next day it starts surging a little and then I have to use the choke some. A little later I have to fully choke it and pull down the throttle. Then it won't run unless continually primed. I checked the fuel line and it has free flow. I took off the gas cap. No go. I'm really stumped now!!! These were the same symptoms I had initially before I cleeaned the carb and rebuilt the pump. . . .l

 
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08-21-09, 07:47 PM   #14  
You've got something getting clogged in the carb....still...


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08-22-09, 08:27 AM   #15  
Take off the carb, take it apart, and soak it in a carb cleaning solution for a couple of hours, then rinse in water and blow out ALL holes in the carb and make sure you soak and blow out the main jet as well. You have varnish build up and the only way to remove it is by soaking.

 
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08-25-09, 08:06 PM   #16  
I'm still wondering about the fuel pump? I think I will check the bowl and see if it has fuel - if not, its the pump, right? I could then put fuel in the bowl and see if it runs for awhile, and if it does, the rest of the carb is OK? I did reuse the old diaphragm in it.

 
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08-25-09, 08:30 PM   #17  
Worth a check to see. You said you put a kit in the pump (new diaphragm), so I figured it must be something in the carb.


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08-26-09, 01:22 PM   #18  
Initially I installed the pump kit, but I didn't remove the carb. So I didn't have the new diaphragm lined up exactly and one of the mtg holes got chewed up a bit. So when I cleaned the carb I reused the old one. It wasn't as limber as the new one, and had some sand on it which I cleaned off. It may be too stiff to work well? If fuel pump is the problem, I will order another one (I suppose there could also be a problem with the vacuum? Not sure how to check this except with my finger on the mouth of the line hose. The line is clear.)

 
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08-26-09, 09:01 PM   #19  
If the engine is turning and the pistons are moving, then the vacuum/pressure pulses are fine. Check the bowl for fuel and go from there.


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09-12-09, 12:24 PM   #20  
Well, I took the top of the carb off and there was a little fuel in the bowl. So I filled it up and reassembled. Its been running fine ever since???

 
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09-12-09, 07:40 PM   #21  
lol...maybe it just needed priming. Sometimes it takes a good bit of cranking to get the fuel all the way up from the tank under the seat to the carb.


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