It would seem my fuel pump died LT15go

ladylake · April 12, 2024, 03:35:52 AM

Quote from: Brad_bb on April 11, 2024, 06:43:31 PM@doc henderson @ladylake is the fuel pump you're using the one that ladylake recommended? That Carter pump says "in tank". Does it need to be in the tank to disperse heat? or can it be in line?

The description is wrong, it's a inline pump and should be mounted close to the tank. Mine runs for years. Steve

EBAY LINK REMOVED BY ADMIN

Chuck White · April 12, 2024, 08:19:12 AM

In any WM fuel tank I have ever looked at, the fitting that the quick-disconnect is screwed into is threaded directly into the top of the fuel tank and there is no nut underneath!

Ben Cut-wright · April 12, 2024, 12:50:29 PM

BB said:
"Given the infrequency, and now knowing what to look for and what to do, I don't think it's worth any modification such as an electric pump or priming bulb."

Did you try what you did when the last new pump didn't...pump? IE: Create a siphon on the fuel line to lessen the suction head on the pump? The pump worked after that. What happened? The suction side was sound enough to create a siphon by mouth. The standpipe in the tank has a coarse strainer. Possible something is blocking it periodically. IT's certainly not unusual for these pumps in that application to be able to pull fuel for some distance. But the fuel circuit must be sound to do so.

A vacuum-pressure tester gauge is very cheap and will reveal whatever problem wasn't corrected before. Suction pressure, output pressure, plugged lines, filters and strainers, and proper crankcase pulse will show up using a vacuum-pressure tester.

If the pump you currently have on that engine isn't bad, installing another, or additional pump, may only be overcoming whatever problem is still there.

ladylake · April 12, 2024, 01:50:40 PM

A electric fuel pump is easy, simple and works great. Steve

Brad_bb · April 12, 2024, 06:16:27 PM

@StimW got me thinking back, and I remembered that I have had a problem in the past with the quick connector at the tank. I think the O-ring in side was bad and letting air in and spoiling the siphon.

@Peter Drouin That's exactly what I was thinking of going out and testing. I ordered a new connector today, but it won't be in til Tuesday afternoon at the earliest. I figured I'd try some vaseline on the nipple and see if it works and maybe could get the through the weekend. If the Vaseline won't hold, maybe one wrap of electrical tape and Vaseline?

doc henderson · April 12, 2024, 06:51:54 PM

My timberking came with the auxiliary fuel pump standard. It is always something. If you want to put some Vaseline on your nipple, please go right ahead.

Wlmedley · April 12, 2024, 07:20:09 PM

Carl said "put some gas in it "

Brad_bb · April 12, 2024, 09:22:53 PM

@doc henderson @Wlmedley

Chuck White · April 13, 2024, 09:08:57 AM

Brad; To check for a "failed" o-ring in the quick disconnect, pull the fuel line off of the quick disconnect and stick it directly into the gas tank, making sure that the end of the line is in the fuel!

If it starts and runs, the o-ring is bad.

Back when I had my mill, I removed the bad o-ring and went to the local John Deere store and they matched it with a ring that they had in stock, so I picked up a few. I don't remember the JD part number!

Brad_bb · April 20, 2024, 03:27:31 PM

@Chuck White

Well, I got a new female side of the quick connect that has the O-ring, and got it installed. There was some fuel in the filter I could see so some had moved into the filter while it sat. Could have just been from moving the line around. I knew it would start right up, which it did, but I engaged the blade (throttle up) and went about 3 ft and it rolled back and died with the filter mostly empty. Tried 3 more times with the same thing happening. I pulled the fuel line of the pump and pointed it down to allow gravity to pull a spurt of fuel, and did this several times until there was a steady pulsing of fuel. Reconnected it and started and go the blade engaged and was able to cut the last 3 slices on the small cherry log. I'm pretty confident this has fixed the issue. A bad O-ring in the quick disconnect that was sucking air. Incidentally I came across my an old female quick disconnect that I replace 4 years ago or so. I'll see if I can get the o-ring out and find a replacement for next time. After I get some more milling time I'll know for sure if it's fixed. I'll get back on here if any more problem. Thanks all!

Ben Cut-wright · April 20, 2024, 05:23:08 PM

Quote from: Brad_bb on April 20, 2024, 03:27:31 PMWell, I got a new female side of the quick connect that has the O-ring, and got it installed. I knew it would start right up, which it did. It died with the filter mostly empty. Tried 3 more times with the same thing happening. I pulled the fuel line of the pump and pointed it down to allow gravity to pull a spurt of fuel, and did this several times until there was a steady pulsing of fuel. Reconnected it and started and go the blade engaged and was able to cut the last 3 slices on the small cherry log. I'm pretty confident this has fixed the issue. A bad O-ring in the quick disconnect that was sucking air. Incidentally I came across my an old female quick disconnect that I replace 4 years ago or so. I'll see if I can get the o-ring out and find a replacement for next time. After I get some more milling time I'll know for sure if it's fixed. I'll get back on here if any more problem. Thanks all!

The engine started and ran until it stopped. Your description reads like you took the output hose off the fuel pump? Since you say there was "steady pulsing", the engine must have been rotating/cranking at that time.

Essentially the problem presents exactly as it did before you replaced the O-ring. A "prime" procedure was used again this time. Anywhere air is allowed to enter the fuel line prior to the pump, force of atmospheric pressure will overcome negative pressure of the pump. Once there is enough loss of negative pressure to prevent fuel flow...the engine will die...and the line will have to be primed once again.

Fuel leaks won't visibly show up most times at the connection you replaced. Proper vacuum or pressure testing would quickly reveal a leak in that area. If your new pump could not prime itself on an empty line I would be finding out why. Obviously the "pressure pulse line" is providing enough force to operate the pump. That circuit will have to be even more sound when pumping actual liquid because the fluid being pumped restricts/resists the pump diaphragm.

Brad_bb · April 20, 2024, 07:47:34 PM

I'll try to be more clear. After putting on the new fitting, the line was mostly empty. I did not want to suck on the fuel pump end of the line because it had some wetness with fuel. I essentially relied on the fuel pump to remove the air and get fuel going. That is the reason it took 4-5 tries, to really get the siphon going and clear the air out of the line/get fuel in the line. I think we are there now. Running it more will prove it. I run it tomorrow. They were weed spraying the fields around me and I didn't want to stick out in the open shop, but rather avoid any drift and stay inside today.

Peter Drouin · April 20, 2024, 10:37:22 PM

I never undo that connection, I fill the fuel tank on the mill. On one of my old lt40s I put grease on the outside of it with it together and never looked back. On and off, on and off will mess up the O-ring. You better buy a box of o=rings if you're going to keep taking it apart.

Chuck White · April 21, 2024, 08:36:24 AM

I found that putting a light film of oil or grease on the male piece helps to save the o-ring problem!

Ben Cut-wright · April 21, 2024, 01:12:01 PM

Quote from: Brad_bb on April 20, 2024, 07:47:34 PMI'll try to be more clear. After putting on the new fitting, the line was mostly empty. I did not want to suck on the fuel pump end of the line because it had some wetness with fuel. I essentially relied on the fuel pump to remove the air and get fuel going. That is the reason it took 4-5 tries, to really get the siphon going and clear the air out of the line/get fuel in the line. I think we are there now. Running it more will prove it. I run it tomorrow. They were weed spraying the fields around me and I didn't want to stick out in the open shop, but rather avoid any drift and stay inside today.

"Siphon" (from any source) refilled that empty fuel line several times and the problem reoccurred. One more part was replaced this time but there was no test to ensure the real cause or the actual fix. Simply starting and running for a few cuts hasn't, so far, proven it's fixed.

What I was asking was where did you disconnected the fuel line when you got the "pulsing" fuel results? Surely it was after the fuel pump in order to have pulsing and cranking the engine to operate the fuel pump??? That type pump can move a surprising volume of fuel when it's working correctly and the fuel circuit is sound. Observation is subjective of course, as are most performance specifications for the pulse type diaphragm pumps.

Requires almost no head pressure to push fuel out an open port at the pump. Doesn't take much but the pump must develop more head pressure in order to move the fuel through the line then on to the carb. When the float needle is closed maximum head pressure will be created.

Did anyone suggest checking the fuel cap? It must be vented, or the tank must provide other vent sources, in order to allow atmospheric pressure into the tank. When the vent isn't working the pump suction head will increase to the point it can no longer move fuel. Opening the cap or the pump inlet line can admit atmospheric pressure back into the tank. But the suction head will again reach its maximum and the pump will eventually cease to provide fuel to the carb.

A cheap analog vacuum/pressure gauge will diagnose your problem in short order, or CONFIRM a fix even quicker.

ladylake · April 21, 2024, 01:19:29 PM

Get that electric pomp on there and mount it down by the tank. it's a lot easyier to pump fuel up than to suck it up that far. Steve

Ben Cut-wright · April 21, 2024, 01:35:48 PM

Quote from: ladylake on April 21, 2024, 01:19:29 PMGet that electric pomp on there and mount it down by the tank. it's a lot easyier to pump fuel up than to suck it up that far. Steve

The original pump has been replaced. While it is still possible that the pump is the problem, it should be verified and all other possibilities eliminated prior to modifying the existing system in any way.

Installing an electric pump creates an often overlooked additional fire hazard. When the engine stops for any reason the diaphragm pump stops pumping fuel. An electric pump, with no additional safeguards, will continue to pump fuel if a fuel line fails or a fitting leaks.

Not to oppose using electric fuel pumps in certain circumstances. Only pointing out that they won't resolve all problems, such as a suction side leak or closed tank vent. And, without thoughtful implementation, can add additional risk factors.