[2EGS]

Hi guys,

If I could pick your brains b4 tearing into things... While mowing for the first time last week, my 446 started randomly stalling out. When this happens, I can see that all the fuel is gone from the fuel filter. After it stalls. And sits for a few seconds the filter fills right back up simply from gravity allowing gas from the tank to flow. Tractor starts back up runs fine for a bit and the same thing happens again. This started about 15 minutes into mowing. No set amount of time in between occurrences, but seems to trigger more frequently on hard right turns. If I can hit the choke quick enough it will perk back up then I have to shut the choke back off right away. If I can't, it will just shut off like running out of gas. I adjusted the one needle that van be on this carb last night, did some mowing to test, and still occurring. This is a Nikki carb by the way. B43m engine.

So does sound like the fuel pump is going bad (standard vacuum style pulse pump), or a maybe a float issue? I have purchased both to replace (not installed yet). New float is brass.

Tank vent is inspected and fine. Fuel line is newer (last year). Replaced fuel filter when this started occurring. When I pulled the filter to change it there was good strong flow from tank.

Thanks, Ed

 

[RFngersoll]

To me, it does sound like a fuel supply issue (fuel line, filter, vent, pump, float). How does the float needle and inlet passage look? I thought the Nikki's have a fixed jet that you have to unscrew and clean.

 

[Lionel]

How warm is your tractor getting when it starts stalling out?

Test,
When cold, everything works correctly? Idles up and down, no issue?

Don't mow, just go for a drive around,, hard right turns right away, still working correctly? Motor should be a bit warmer but not overly hot, (not working hard)

Start mowing, problem shows up?

 

[2EGS]

Lionel,
Thanks for the reply. No trouble at first just driving around. Tried mowing again and started with the same behavior. Pushed it for a while and it didn't do it for a bit, then started acting up again. Didn't have any trouble while turning today though. Just random. Same symptoms though.fuel filter would empty and tractor would stall. After stalling gravity filled filter right back up, would start right up and go til it happens again.

I should state, I installed the new brass float and set the height and today's behavior was in spite of the new float.

Thanks, Ed

 

[2EGS]

Rfngersoll,

Fuel line is about a year old, vent cap on tank is clear, needle and seat good. Installed new brass float, no change. With top half of carb off, cranked engine and fuel shot a good 15 inches from inlet inside carb. Wondering if pump may be weak though and not keeping up with demand? Can the carb suck fuel past the pump on its own if diaphragm doesn't seal completely on non pulse part of cycle?

Thanks, Ed

 

[Lionel]

2 things,

So, it sounds like everything is in working order,, including you've mounted a fuel filter that I assume you can see.

Originally, the tractors I've restored didn't come with fuel filters, and of course, I changed that to having a fuel filter. What they had before though, is a little fuel strainer at the bottom of the fuel tank which is supposed to keep junk from contaminating the fuel system. Only problem with that, is they shrivel up, and they themselves could be a source of blockage. Does yours have the strainer? It's connected right at the inlet of the fuel line. That's one of the few things that I got rid of,, with needle nose pliers,, Just a thought,

I also assume you're filter is easy to see? clear type that you can tell if it has fuel in it? The next time you warm it up,, fairly warm,, could you take a little video of that filter,, including a couple inches of inlet hose and outlet hose? What I'm asking is, prior to the thing stalling,, is the fuel in the filter showing air bubbles?

 

[Gordy]

I am leaning to the in tank strainer also, or a somewhat pinched fuel line between tank and filter.

Cheers,
Gordy

 

[Harry]

2 things,

So, it sounds like everything is in working order,, including you've mounted a fuel filter that I assume you can see.

Originally, the tractors I've restored didn't come with fuel filters, and of course, I changed that to having a fuel filter. What they had before though, is a little fuel strainer at the bottom of the fuel tank which is supposed to keep junk from contaminating the fuel system. Only problem with that, is they shrivel up, and they themselves could be a source of blockage. Does yours have the strainer? It's connected right at the inlet of the fuel line. That's one of the few things that I got rid of,, with needle nose pliers,, Just a thought,

I also assume you're filter is easy to see? clear type that you can tell if it has fuel in it? The next time you warm it up,, fairly warm,, could you take a little video of that filter,, including a couple inches of inlet hose and outlet hose? What I'm asking is, prior to the thing stalling,, is the fuel in the filter showing air bubbles?

2 things,

So, it sounds like everything is in working order,, including you've mounted a fuel filter that I assume you can see.

Originally, the tractors I've restored didn't come with fuel filters, and of course, I changed that to having a fuel filter. What they had before though, is a little fuel strainer at the bottom of the fuel tank which is supposed to keep junk from contaminating the fuel system. Only problem with that, is they shrivel up, and they themselves could be a source of blockage. Does yours have the strainer? It's connected right at the inlet of the fuel line. That's one of the few things that I got rid of,, with needle nose pliers,, Just a thought,

I also assume you're filter is easy to see? clear type that you can tell if it has fuel in it? The next time you warm it up,, fairly warm,, could you take a little video of that filter,, including a couple inches of inlet hose and outlet hose? What I'm asking is, prior to the thing stalling,, is the fuel in the filter showing air bubbles?

I was looking for a fuel fitting with the strainer for my 444. I was looking everywhere and could not find one. I stopped into a ACE Hardware on a whim to see if they had it. I asked this older gentleman if they had one. I followed him back to the lawn mower section where he pulled out a cardboard box. Open it and pulled out one saying, "is this what your looking for." Yes it is and I said how many do you have in there. He said three, so I took all of them for $6 each.

Keep the Peace
Harry

 

[RFngersoll]

Like the strainer issue, I’ve heard of the little black disc from the newer style fuel cap falling into the tank and then intermittently blocking the outlet of the tank. The disc expands with the fuel and is barely recognizable until the fuel evaporated from it again. Strange story I know….

Anyhow, if it isn’t the strainer, shine a light in the tank and slosh things around to see if something is intermittently clogging the outlet.


Sent from my iPhone using Tapatalk

 

[curtisfox]

I had this happen on a 51 Ford pickup, it would stall, get out and to see what happened, then get back in and it would start up again. What happend was you set on running board and the piece of rubber that was in would move out of the way, didn't find it till after I took the truck apart for rebuild. Draining the tank quit and a big chunk of rubber was stopping it, pliers pulled it out gas flowed good then..........Curt

 

[2EGS]

Fellas,

I checked the tank with a nice bright led flashlight today. All was clear, and there was no fter screen in there whatsoever. Thinking maybe been removed at some point. Anyhow checked things out under the tractor, thinking maybe my routing is bad. Last fall I had to replace the pressure line from the hydraulic pump. I'm wondering if I inadvertently changed the routing while I was in there? I fiddled around with the fuel line position and went out to mow. I made it an hour b4 any trouble started. Think I will reroute the hose and replace it while I'm down there and see if that does the trick. I'm thinking the steering gear may be pinching it.

I'll keep you posted, Ed

 

[petr]

What condition is your muffler in? If there is a hole or a crack in it, the hot exhaust gets trapped under the hood and causes vapor lock. I had it happen to a 226 and my 446. I chased it for a year before I found the one inlet pipe was cracked. Prior to finding the crack I replaced fuel lines, filter, rebuilt the carburetor, put an electric fuel pump on, changed points, condenser, plug wires, and spark plugs all to no avail. After having the muffler welded my issue went away. So, check your muffler.