Fuel Delivery Problem

Old 05-12-14, 08:46 PM
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Fuel Delivery Problem

I have a Simplicity tractor with a Briggs Vanguard 16 HP twin cylinder engine. This rig is about 16 years old; the engine has about 500 hours on it. Today the engine died on me. I noticed the fuel filter (which is clean) had very little fuel in it. In the process of cleaning out grass and debris to trace the fuel line I noticed that if I lifted up the fuel filter as much as the hoses would allow and then let it fall back into its normal position gas would dribble into filter. I was able to start the engine after doing this several times. The engine ran fine for another 10 or 15 minues until I was finished mowing. Some time did elapse between the engine conking out and me getting it started again so it did have a chance to cool somewhat.

I assume the things that could cause a fuel delivery problem include a blocked gas tank screen, an air leak in the fuel line, a clogged fuel line, or a defective fuel pump. This is a vacuum operated fuel pump. Itís mounted on one of the cylinders and operates off pulsating crankcase vacuum.

Before I go checking out everything in the fuel circuit Iím wondering if thereís a ďmost commonĒ failure mode, for this engine with 500 hours, I should try first.
Old 05-12-14, 09:28 PM
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Is it possible your fuel cap has a clog and is not allowing gas to flow? Try loosening the cap to see if the fuel will drop normally. If so replace the cap.
Old 05-13-14, 09:06 AM
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I am not totally familiar with the simplicity tractors but on my Briggs if the fuel cap vent is clogged, I just lightly poke the hole in the center and wash it out with seafoam and blow compressed air through it and the cap starts venting like new again.

If that doesn't fix it then I would probably change the fuel filter and the fuel line as well.
Old 05-14-14, 12:29 PM
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Fuel Delivery problem also on 1996 Cub Cadet 2135 with approx. 500 hrs.

Search this forum for Cub Cadet and my similar posting threads on my 2135 with 12hp OHV Kohler engine. In the 2 years since posting, I've been dealing with the problem of the thing running for upto an hour and once heats up - just cuts out. Have to wait overnight now in order to re-start to get another hour mowing the next day. Interestingly, in the winter when I use the tractor for snow plowing, I can run it all day and it never stalls out or gets fuel starved.

Thought I found the problem earlier this Spring in the fuel tank with something I couldn't see eventually blocking the fuel outlet port - but after draining completely with a siphon hose and refilling with new gas, it's still cutting out. And as you noted, there doesn't seem to any gas in the fuel filter and as far as I know, its a simple gravity-feed system upto the fuel pump.

When I checked the fuel tank schematics on the Cub Cadet website, it looks like there's some kind of fuel tank connection part/piece that transitions the connection from the gas tank to the hose. Can you check the Simplicity schematics and see if you have anything similar. They tell me that this hole/connection at the transition point is maybe half the size of the 1/4" size of the fuel line and easily obstructed.
I have to disassemble the rear fendor cover in order to get to the back end of the fuel tank on a Cub to work on this and just wondered if you tractor used a similar fuel tank/connection design.

I'm to the point of replacing the fuel pump given the consistent heat-related part of the problem and after, now seeing gas in the fuel filter when I'm cranking the starter and it still doesn't start.


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