B&S Apparent Fuel Supply Issue

I have a Craftsman 18.5 HP riding mower with a B&S 31P777-0299-E1 motor. The motor has a Nikki carb. The mower is years old and has run well. I always run all gas out the engine til it stops before winter storage and always start a new season with fresh gas. A few weeks ago, I cranked it ok per usual and started off on it. After about 30-40 ft, the engine died and would not crank. It behaved as if it wasn't getting gas. Everything checked out visually, so I replaced the fuel filter. Still wouldn't crank. I figured carb problem and put it in the shop. The shop had it for awhile and reported that it cranked and ran well for them. I brought it home and used it to cut the yard and later to distribute fertilizer. Yesterday, I started to cut grass. It stated and ran great , but died again without recranking after about a minute. I put it up with plans to try to figure out what was wrong. About 2 hours later, I tried again and it cranked right off. I cut 1-12 acre with absolutely no problem. I an bewildered by this problem that seems to come out of nowhere and then disappear with no after affects. Any suggestions will be welcomed.
Larry

Something to try. Run the engine until it dies. then without turning the key off, crank the engine and see if it will start. If then engine doesn't start, then turn the key off and then back on and see if it will start. If it restarts after turning the key off then the plastic tip on the fuel solenoid plunger has come loose. You will need to either replace then solenoid, epoxy the tip back on the plunger, or remove the tip and just run it without.

You say it did not crank.
The cranking circuit goes from the starter through the PTO switch through the brake/clutch switch to the solenoid.
Make up a small bridge wire to go from the hot terminal on the starter solenoid than the small trigger terminal at the base of the solenoid and a normal jumper to go from the battery - to the solenoid.
When it won't crank try the small lead first , works = problem with the cranking circuit
Dosn't work try the normal - jumper, works = bad grounding dosn't work = problem with the cranking circuit.

Read you operators manual, every thing you have to do before starting will have a safety switch on it and the cranking circuit is a daisy chain so if there is a bad switch, broken wire, bad connection in the chain you will get random no crank situations.

When I said it would not crank, I probably mis-stated. I should have said it would not restart. It cranked OK after dying, but would not restart. There was nothing wrong with the switch to starter circuit. Everything pointed to a lack of fuel and after it sat for about 2 hours, it started per usual and I was able to cut 1-1/2 acres, shut it down for cleaning and restart to move to storage. So this makes twice that it shutdown due to an apparent lack of fuel to the engine, sat for awhile and later restarted and ran like nothing ever happened multiple times. At this point, I tend to lean toward the first response that leaned toward the anti-afterfire solenoid being bad and must wait until it decides to shutdown again to follow that recommended test procedure. The only issue with that recommendation is that in the 2 times it has shutdown, the key was turned to the off position before attempting unsuccessful restarts. The recommendation stated that, on shutdown, if the engine would not restart immediately without turning the switch to "off" but would restart after turning the key to "off", the problem was probably the solenoid. If that is the case, my simple mind seems to think that the engine should have restarted if the solenoid was the problem.

My test procedure was to check to see if the tip was coming off of the plunger. You could still have a bad fuel solenoid. When it dies after running turn the key on and off and listen to see if the solenoid is clicking. If no click then you have a heat related failure of the solenoid.

ILENGINE said:

My test procedure was to check to see if the tip was coming off of the plunger. You could still have a bad fuel solenoid. When it dies after running turn the key on and off and listen to see if the solenoid is clicking. If no click then you have a heat related failure of the solenoid.

Click to expand...

Thanks, ILENGINE, for the clarification! It sure sounds like you are on the right track. Now it's just a matter of waiting til the next occurrence.

You can eliminate the solenoid by replacing it with a bolt.
Problem goes away = bad solenoid.
Just note ,it is illegal in many areas to remove the solenoid and there are massive fines for doing that.
Mr Joe Nobody is an easy target for the Enviromental Zellots or beauracrats trying to justify their existance so it is a diagnostnic tool only.

Old thread, but a good one...

ILENGINE, you said that to deal with a loose solenoid tip, the OP would,

ILENGINE said:

need to either replace then solenoid, epoxy the tip back on the plunger, or remove the tip and just run it without.

Click to expand...

Which epoxy, or epoxies, would you suggest for this application? I have some T-88, but it is not gasoline-resistant.

P.S. Thanks for the test procedure. I would add that the tip won't necessarily come down with the plunger when you turn the key off, so the person testing may have to try the "turn-off, then try to start" sequence more than once.

I have used the two part epoxy in the past, but if you have a hot glue gun that works too. The hot glue is gas resistant. Have repaired plastic tanks that have split or cracked with hot glue when a tank was no longer available.

rfisher said:

Old thread, but a good one...

ILENGINE, you said that to deal with a loose solenoid tip, the OP would, Which epoxy, or epoxies, would you suggest for this application? I have some T-88, but it is not gasoline-resistant.

P.S. Thanks for the test procedure. I would add that the tip won't necessarily come down with the plunger when you turn the key on, so the person testing may have to try the "turn-off, then try to start" sequence more than once.

Click to expand...

(Edited, I had originally said, "when you turn the key off".)