Hot fuel delivery problem

[schneidvt]

I have an ingersoll 3014 that has developed a new problem. After running fine for an hour or so it will stop pulling fuel. The fuel filter goes dry and as I crank it I can see a little fuel fluctuate in the bottom of the fuel filter. After I let it cool off, I can crank it over and it will fill up and run like normal. Any ideas what could be causing this?

 

[hydriv]

You are apparently suffering from fuel "vapour lock". This can be an elusive issue to sort out. More often than not, vapour lock is caused by high temperatures under the hood. Some of things that can cause those high temps are:

1. rodent nests under the engine cowlings that block air from flowing over the engine block. Solution: remove the tins and clean the area. Be sure to check under the flywheel.

2. a muffler or exhaust piping that is failing. All connections must be tight. The muffler can develop holes that cannot be seen because of the insulation layer covering it. Hot exhaust gasses that exit UNDER the hood, instead of leaving that area by way of the tailpipe can cause a dramatic rise in the temperature under the hood.

3. gasoline with a higher percentage of alcohol will boil at a lower temperature than older gasolines with no alcohol or low amounts of alcohol.

4. Timing issues. Make sure that the valve lash is set correctly. If the engine has points, then make sure they are set properly. Gap the spark plug to spec.

5. Too lean of a fuel mixture can also make the engine run hotter but I doubt that is your problem.

6. Check the cooler for the hydraulic oil. It must be CLEAN or it will not cool the oil. Hot oil will cause the under hood temps to rise.

7. Make sure all the fuel hose clamps are tight so that no air can get sucked into the fuel line.

8. Too high of a compression ratio can also cause high heat and that can happen when carbon builds up in the combustion chamber. Removing the head to clean away all the carbon including the area under the valves is a routine maintenance item for many engines.


You could try removing the hood from the tractor completely as a test. Go and cut the grass for an hour on a hot day with no hood and see what happens. If you have changed nothing on this tractor since the last time it worked perfectly, then it would seem to be some sort of maintenance issue. It's a matter of figuring out whether it is one thing or several small things that are causing it. Most of the things I listed above are procedures that the engine manufacturer expects you to do every 500 hours or so. Nothing runs forever without being cared for.

 

[schneidvt]

Thanks for the tips, I'm planning on taking the air compressor to it this afternoon and blow any junk out of the cylinder heads and check that I don't have any loose hoses off of the fuel pump. As for the fuel I run 89 with an ethanol stabilizer. I have heard of some people having issues with the fuel pumps and the fuel cutoff solenoid, maybe I can figure out a way to test that while I'm in there. For reference it is a 14hp briggs vanguard with 1200 hours. It has been by far the most reliable mower I have seen.

 

[hydriv]

If mice got into the shrouds during the winter and built a nest, then that problem will not be solved with compressed air and a blowgun. According to your initial post, the engine runs fine for an hour or so until under-hood heat causes the fuel to percolate. At that point, no fuel pump will be able to suck vapour and keep the carb's float bowl filled. I don't see this as a fuel pump issue and certainly not a fuel cutoff solenoid problem either.

This is why I suggested removing the hood and running the tractor hard while under load, for well over an hour. Doing so will tell you that the problem is with heat build up and not with float levels or the solenoid. I am suggesting that you begin by making sure all of the routine maintenance items are taken care of. That's how PRO mechanics go about it. They set the valves, timing, plug gap etc in accordance with the manual to ELIMINATE them as the possible source of the problem. You seem to want a 5 minute fix and that rarely works out. As you said, the tractor has 1200 hours on it and I'm betting that you are not the original owner. If so, you likely have no idea if ANY service work beyond changing oil and filters has been done. Engine manuals are available to you at the Briggs and Stratton website. if you don't know what you are doing, then perhaps you should take the tractor to someone who does. After all, a new engine will cost you $1500.00 if you end up damaging it by not getting to the real problem now. High heat can destroy engines. But as they say, your tractor, your money. Good luck with the repair.

 

[Willl]

Tank vent clogged ?

Did you try removing fuel cap when it dies ?

 

[schneidvt]

I took your advice and went ahead and pulled all the heat shields on the cylinders. The outsides looked good but the valley was caked. I appreciate your input. I wouldn't have thought to clean this area otherwise due to having to remove all the throttle linkages to get the shield out. Turns out in the end the problem was the vacuum line from the valve cover to the fuel pump. I guess as the hose softened up from the heat it was leaking.

I will add that I am the original owner and this tractor is what I learned general maintainance on, which is again why I am so impressed with this briggs motor for making it this long.

Thanks again, Jason

before & after pics


actual culprit

 

[hydriv]

A well-cared for Vanguard should last at least 2000 hours. The key is proper maintenance in a timely manner. As you found out, looks can be deceiving. All too often there are nasty gremlins hiding from your eyes and those can greatly affect the life of the engine. Air-cooled engines cannot be properly cooled if the fins are clogged and other areas have heavy build-ups of oil and dirt. So far, you have found TWO problems. Most likely, the problem you were having will now be solved. However, if you have not performed the other tasks I mentioned, then you run the risk of a shortened engine life. At 1200 hours, you are past the half-life of the engine. How many more hours you will get from it is in your hands. I'm glad that my advice assisted you in discovering what was wrong. If you found value in what I said, then follow the rest of my advice and protect your investment. A little time and money spent now can save you many hundreds down the road.