diagnose fuel delivery issue

[jives]

Okay, I've tried most everything, now need second/third/. . . opinions.
issue: 1986 Wheel Horse tractor, Kohler 16 hp K341 single cylinder. Out of the blue stopped running. After sitting a bit, runs for a minute. Same story again and again. Not a temperature issue.
Fixes, diagnostics:
1. Has spark.
2. Fuel drained, replaced with fresh 90 octane, non ethanol. Did not, however, check for sludge around fuel outlet hole and strainer.
3. Entire fuel line and filter replaced with new.
4. Carb main jet removed, cleaned out.
5. Plenty of carb cleaner sprayed inside.
6. Fuel line from fuel pump to carb removed at carb end. Fuel is being pumped.
7. Removed carb bowl multiple times after engine stalled. Bowl has fuel, did notice some gunk, even after multiple times cleaning it out. Fuel bowl float seems to move well, but I have not removed carb and done a thorough cleaning and gasket replacement (yet).
8. When engine stalls the clear fuel filter is empty of gas. After sitting the filter fills back up (gravity feed from tank). Engine will crank and start.
9. Gas cap venting could be an issue, as of yet have not tried to loosen cap as the cap seems to be broken and has venting. But I have not tried to loosen the cap (just now thought of this obvious thing to try).

Thoughts?

 

[RPH]

Cap, fuel out of tank draws a vacuum on it. Fuel stops flowing. Loosen cap.

 

[Walkers]

Fairly simple motors. Check the points, should have 20 thousandths gap when open. Point gap controls timing, so be accurate. On mine the wiring was getting to be a pain. Wire at the fuse holder broke but would still fire, then quit. Replace the coil, plug, and wire. If it has the magneto, check the gap to the flywheel. Otherwise check your other on/off wiring, bypass it if you know how to make sure you don't have a hidden broken connection.

 

[Monza Harry]

More common on small motorcycles but a few GardenTractors (yard etc. equipment) will have a shut off with a filter/screen check for blockage/debris, as well as the cap issue you mentioned. Also run some (STP?) type carb/fuel injector cleaner through it regularly. Add a bottle to your 5 gallon gas can for the season, Sta-Bil isn't a horrible plan either as a Preventative Maintenance plan. Harry
EDIT: Also check the vacuum line to the (external?) fuel pump a small crack will affect pump output considerably.

 

[PCustoms]

Pull the line form the filter, use an air gun and blow it back to the tank. Odds are it's gunked. Alternatively you can change the line.

 

[Garcky]

Okay, I've tried most everything, now need second/third/. . . opinions.
issue: 1986 Wheel Horse tractor, Kohler 16 hp K341 single cylinder. Out of the blue stopped running. After sitting a bit, runs for a minute. Same story again and again. Not a temperature issue.
Fixes, diagnostics:
1. Has spark.
2. Fuel drained, replaced with fresh 90 octane, non ethanol. Did not, however, check for sludge around fuel outlet hole and strainer.
3. Entire fuel line and filter replaced with new.
4. Carb main jet removed, cleaned out.
5. Plenty of carb cleaner sprayed inside.
6. Fuel line from fuel pump to carb removed at carb end. Fuel is being pumped.
7. Removed carb bowl multiple times after engine stalled. Bowl has fuel, did notice some gunk, even after multiple times cleaning it out. Fuel bowl float seems to move well, but I have not removed carb and done a thorough cleaning and gasket replacement (yet).
8. When engine stalls the clear fuel filter is empty of gas. After sitting the filter fills back up (gravity feed from tank). Engine will crank and start.
9. Gas cap venting could be an issue, as of yet have not tried to loosen cap as the cap seems to be broken and has venting. But I have not tried to loosen the cap (just now thought of this obvious thing to try).

Thoughts?

Could be the cap vent, but it could also be a clogged fuel valve on the tank. Usually, those have a screen on them that protrudes into the tank. If that screen is clogged, fuel can't flow properly. Usually, you can unscrew that valve from the tank and clean the screen. The slow refill of the filter would seem to point toward a bad cap vent or clogged screen in tank.

 

[whitesco]

Could be cap for sure, would try that as it's the easiest possible thing. When is it stalling? Could be a clogged idle jet - I have a generator that runs like a top under load but crappy at idle that I need to clean.

 

[Mike65]

I would suggest remove the carb do a complete clean & rebuild. If you have found gunk in the fuel bowl multiple times it may be in the carb passages.

 

[cherokee]

Several years ago I had a Datsun, one day it stopped running. Had 3/4 tank. When I took off the gas cap you could hear air rushing in and then a POP. Like you sucked all the air out of a pop bottle. Fairly new car. Dealer gave me a new gas cap and no other issues. Guess that was the only vent.

The sludgy in the bowl would be a worry for me, plastic or metal tank? Did you replace the fuel lines when you did the filter, real cheap to do that one. I usually start with cheap and easy and work up from there. Once and a while you get lucky.

 

[gizardlizard]

Agree with Mike. ASSuming this unit was just brought out of storage to mow and sat all winter. Classic dirty carb symptoms, needs to be taken completely apart and cleaned preferably in an ultrasonic cleaner. Literally 100% of engine problems I encounter in the spring are dirty carb related.

 

[theoldwizard1]

Get rid of the mechanical fuel pump. Use a vacuum operated one

 

[backupbeeper]

Make sure the needle valve on the carb float is clean and flows well

Take the bowl off the carb, and make sure fuel flows out the needle valve . And that it stops flowing when your raise the float with your finger .

Be sure to thank your congressman for requiring ethanol in the gasoline .

 

[vtcat]

Pull fuel line off the carb and turn the engine over. If fuel comes out of the pump good, then it's the carb.
If it doesn't then pull the fuel line from the tank off the the fuel pump. Hold it as close to the floor as you can
and see if it will gravity feed. The more fuel in the tank the better. You may have to blow into the tank to
get started, but it should run by it self after that. Look into the tank to see if the screen on the fuel shut off looks ok
and is open all the way.

 

[joel_400]

I have a whole pile of old Wheelhorse tractors. A few of them in the spring can be temperamental. I'll usually take an blow gun and a rag and slightly pressurize the rear fuel tank momentarily to push the fuel forward to the pump at least. After that they usually fire right up. The pumps aren't that great for pulling the fuel that far, so this saves on cranking...also serves for a leak test...just don't do it around open flames! Haha When you say your filter is emptying out it leads me to think you've got either a blockage at the tank valve or the caps not venting properly. Hopefully you have the Kohler/Carter carb on yours vs the Walbro. The Kohler carb is one of the simplest, and in my eyes, best small engine carbs ever made. Adjustable high and low speed fuel mixture screws make it very easy to tune! And they always seem to be more forgiving with today's **** fuel.
Joel

 

[My Old Tools]

trash in the tank

 

[dvblanch]

Remove tank fill 1/3 way w hot water& good dose of simple green shake it around hard for awhile empty & repeat a couple times.Rinse well & blow it out as good as possible . A bottle of drigas splashed around & dumped will help remove any water that has not evaporated.

 

[jives]

Update. . . Stuck a brush into the mostly full fuel tank to blindly clean the fuel outlet area, left the gas cap loose, and ran it for 5 minutes, then shut it off. Okay, perhaps only gunk in the tank, I'll need a better cleaning after draining the gas. I have not yet rechecked the carb fuel bowl for residue.

In the spring I use the tractor with front blade to push gravel from my grass back into my driveway or into the road. Works well, but this year due to the problems had to do it the old fashioned way -- with a rake. uggh. The town did a serious number on my grass as in mid-winter the road was turning to muck so they laid down loads of gravel. The first snow plowing after that put tons of gravel into my grass.