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Discussion Starter #1
Hey guys,

Looking for some help here, I have a JD D105 mower that recently encountered a crank but no start condition. I was mowing the grass and stopped to empty the bagger and when I tried to start her up, she would just crank. This is what I've tested/replaced so far:

1. Replaced Spark Plug (the old one had 152 hours on it and was never replaced)
2. Replaced fuel filter (original one in the mower with 152 hours on it)
3. Disconnected the fuel line from the fuel vacuum pump and tried to kick it over - noticed that no fuel was coming out of the fuel pump which made me think it was a bad diaphragm inside the fuel vacuum pump. I replaced it with a replacement Briggs and Stratton but apparently that did not fix the issue.
4. Drained the fuel tank and blew out the vacuum and fuel line with a compressor (thinking there was a blockage)
5. Removed carb and cleaned it out.
6. Checked and inspected all of the fuel/vacuum lines, they all look fine with no cracks or breaks in them
7. Checked the battery with voltmeter and load tester - passes both voltage requirements and CCA's.
8. Disconnected and cleaned both the seat safety switch and the brake safety switch
9. Checked the 20a starter fuse, is visibly OK and passes an OHM test.

I'm at a complete loss with this thing...I've been the original owner of this mower and have never had an issue in the 152 service hours I've put on it...any helps or suggestions would be greatly appreciated...I've even called a couple of "mobile mechanics" and after telling them everything I've done they are at a complete loss as well. One interesting feature is that I've read/seen that some people bypass these vacuum fuel pumps all together in favor of a gravity fed system (saw one video where a guy ran a 5/16 fuel line from the tank to the carb and it fixed the issue)...When I try and crank the mower (even after replacing the vacuum fuel pump) I never see the fuel filter fill up with gas which is odd...
 

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Discussion Starter #4 (Edited)
I do, I had my wife crank it over while I grounded the spark plug against the heat shield near the oil filler neck (which covers the spark plug wire and solenoid) and can visibly see a spark. I was able to get her started by spraying starter fluid into the intake pipe but she will run for a couple of seconds then die...its almost like its being starved for fuel. I'm a tad bit concerned that the vacuum pump doesn't spit out any fuel if you crank it even with the new fuel pump, I saw a video that there can be "air" in the lines - anyone seen anything like this?

My old mower was gravity fed so this vacuum ******** seems to be overly engineered...is it normal for the fuel filter to just have a tad bit of fuel in it? It's almost as if nothing circulates into the pump to feed the line that goes into the carb...
 

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I do, I had my wife crank it over while I grounded the spark plug against the heat shield near the oil filler neck (which covers the spark plug wire and solenoid) and can visibly see a spark. I was able to get her started by spraying starter fluid into the intake pipe but she will run for a couple of seconds then die...its almost like its being starved for fuel. I'm a tad bit concerned that the vacuum pump doesn't spit out any fuel if you crank it even with the new fuel pump, I saw a video that there can be "air" in the lines - anyone seen anything like this?

My old mower was gravity fed so this vacuum **** seems to be overly engineered...is it normal for the fuel filter to just have a tad bit of fuel in it? It's almost as if nothing circulates into the pump to feed the line that goes into the carb...
It sure sounds like you still have a fuel blockage. I'm betting after all that cranking the spark plug is still bone dry. If you crank the engine with the hose disconnected from the vacuum fuel pump and fuel does not squirt out with each revolution of the engine - STOP - first solve that problem before moving on.

The reason it is running for a few seconds after spraying starter fluid is because it is running from the fluid, not gasoline.

This may sound silly but do you have a plastic container of any kind that you can put some gasoline in and from which you can attach a rubber hose to the input of the fuel pump? This would eliminate the entire fuel delivery system prior to the fuel pump.
 

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Sometimes blowing the line does not help...if you have a piece of rubber inside the hose that is acting like a flap / check valve...post #5 last paragraph is not silly at all and is likely to pin point your problem...if you decide to bypass the fuel pump make sure that you have a shut off valve and don't forget to use it every time..as for the fuel filter...I see that you replaced it...did you use a like diameter filter?...if not that can cause problems similar to what you describe...I realize you did that after your initial problem...but you may have solved one thing...and caused another...if fuel pump iturns out to be the problem (despite being replaced)...consider a low pressure electric one
 

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Sometimes blowing the line does not help...if you have a piece of rubber inside the hose that is acting like a flap / check valve...post #5 last paragraph is not silly at all and is likely to pin point your problem...if you decide to bypass the fuel pump make sure that you have a shut off valve and don't forget to use it every time..as for the fuel filter...I see that you replaced it...did you use a like diameter filter?...if not that can cause problems similar to what you describe...I realize you did that after your initial problem...but you may have solved one thing...and caused another...if fuel pump iturns out to be the problem (despite being replaced)...consider a low pressure electric one
I was mainly advocating attaching some type of alternate fuel tank for testing purposes only. That's why I was suggesting a hodge podge. If it pumps fuel and runs from the alternate tank / jar then you KNOW you have a blockage in the tractors tank or supply line.
 

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My 265 had spark and fuel and wouldn’t start. Module went. It did show module symptoms like cranking fast, then cranking slow, backfiring. Replaced with a Nova II. That lasted 10 plus years. When that one died it just spun over, but had no spark.
 

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My 265 had spark and fuel and wouldn’t start. Module went. It did show module symptoms like cranking fast, then cranking slow, backfiring. Replaced with a Nova II. That lasted 10 plus years. When that one died it just spun over, but had no spark.
Did your 265 have a simple magneto ignition coil or did it have points, ignitor, etc? These little single cylinder B&S engines don't need much to generator spark. Just pass the flywheel magnet past the ignition coil. :)
 

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Oops, just reread that it starts on ether, probably not module. The 265 is electronic, no points. I think it’s a 17 HP Kawasaki. It turned 30 this year so I retired it to hunting camp in WV. I’m in MD so I can’t run out and check.
 

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I was mainly advocating attaching some type of alternate fuel tank for testing purposes only. That's why I was suggesting a hodge podge. If it pumps fuel and runs from the alternate tank / jar then you KNOW you have a blockage in the tractors tank or supply line.
I agree...but OP mentioned that he heard of bypassing the fuel pump as a permanent solution...just suggesting that if he goes that route that he would want the shut off valve on the line
 

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Discussion Starter #12 (Edited)
Sometimes blowing the line does not help...if you have a piece of rubber inside the hose that is acting like a flap / check valve...post #5 last paragraph is not silly at all and is likely to pin point your problem...if you decide to bypass the fuel pump make sure that you have a shut off valve and don't forget to use it every time..as for the fuel filter...I see that you replaced it...did you use a like diameter filter?...if not that can cause problems similar to what you describe...I realize you did that after your initial problem...but you may have solved one thing...and caused another...if fuel pump iturns out to be the problem (despite being replaced)...consider a low pressure electric one
I decided to blow out the lines to see why the fuel was never reaching the vacuum pump, I could tell that both the vacuum and fuel hose were both blowing out with no obstructions. As mentioned I'm used to gravity fed systems so this vacuum fuel pump seems like overkill in the engineering department (just my .02). I was going to stick a funnel in the fuel line that goes to the carburetor and fill it with gas to see if a gravity fed system would keep the engine running but I was inundated with work meetings and was trying to use my time constructively :).

Yes, I replaced it with the exact same Briggs and Stratton (I want to say it was a 808498 but I will double check) because I read somewhere that the cheapo ones you find on Amazon (the ones that have the philip's head bolts on them) go bad relatively quickly and/or 1 in every 5 are DOA so I shelled out the extra cash for the OEM Briggs.
 

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I agree...but OP mentioned that he heard of bypassing the fuel pump as a permanent solution...just suggesting that if he goes that route that he would want the shut off valve on the line
I don't think that would work as the D105 fuel tank is in the rear of the tractor so gravity feed won't work. That's why it has the pump. I have a small Ariens with the same engine that is built very similar except my battery is under the seat and the fuel tank under the cowl (the opposite of the D105) so my fuel delivery is gravity.
 

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I would get something like this to see if the fuel pump is the issue.


There are several models. I used one decades ago on my Fiat 124 Spyder. They had notoriously bad stock fuel pumps. Put one in front of it so I could turn the key to run for a few seconds to prime the other pump and then start the engine easily.

It really sounds like to pump is loosing prime and that will make it really hard to start.
 

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I put a generic electric pump on my Vermeer stump grinder with a four cylinder Wisconsin. If it’s the pump that will fix it. Got mine at PepBoys for about $25.
 

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I put a generic electric pump on my Vermeer stump grinder with a four cylinder Wisconsin. If it’s the pump that will fix it. Got mine at PepBoys for about $25.
Keep in mind this is a lawn mower with a single cylinder B&S engine and a small magneto charging system that just barely keeps the battery charged. I doubt the needle and seat on the tiny carburetor can withstand much fuel pressure. There is a reason that millions of these mowers have been using small vacuum operated fuel pumps for many decades.... they work just fine. :)
 

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My suggestion was to use the pump as a diagnostic tool. It sounds like there is not enough fuel being provided by the current pump. That could be for one or more of several reasons. Since the electric pump does not require the engine to be producing any vacuum, it eliminates a couple of potential problems.

I do know that the B&S engine on my small mower took about 20 shots of starter fluid to get running the first time this year. Last year, when it was new, it started first pull every time. Since I got it started, it has continued that great behavior. I guess it just didn't like being left alone for several months. The problem with using the electric starter more than a few seconds more than a few times in close proximity is that the starter will overheat. Do that too many times and you'll need a new starter. That is probably a lot more expensive than the cheap fuel pump.

The point about too much pressure is a great one and I would get the lowest pressure pump to minimize the issue.
 

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I have to agree with too much pressure. The pump needs to be replaced with a pump equal in pressure. When dealing with a carb too much pressure and you will have problems with the needle and seat leaking. With a fuel injected setup you run the risk of running richer than you would have normally because of the increased pressure.

Looking at the situation it starts and runs a brief amount of time using starter fluid? If so then the ignition is ok. Granted you changed the pump but your still not getting gas to the carb. Possibilities of fuel line blockage, problem with the new pump, or simply the possibility of little to no prime. If it were me I would setup a temporary gravity feed using caution as to not blow up something and or start a fire. I suggest that you have someone hand with a fire extinguisher just in case. Once the gravity system is setup manually dump a little gas down the carb and manually choke the engine slightly if possible.
 

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My post above is a suggestion for making sure you don't have a run issue problem it is not meant to be used as a solution. I'm one that favors actually trying to solve a problem instead of putting a Band-Aid on it. Once you make sure the engine does indeed run correctly then I would go back to solving the problem. A stupid question but have you checked the gas tank for adequate level? How old is the current gas and can you see any debris in the tank?
 
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