McCormick international 434 - Air in fuel system

[ant3000]

Novice International Owner - purchased in the Autumn from a chap who he’d stripped the engine and fitted a new head gasket etc

i’m now starting to put it into use but after a few runs the engine has just died? Checked the fuel tank and while it seemingly had a fair bit in the bottom of the tank I figured it would be best to eliminate the obvious and top it up.

My first thought was that it might have pulled some air into the system as the fuel has run to to front / back or tank as I‘ve travelled up / down hill so I made an attempt to bleed the fuel line and it fired up and allowed me to do a few more circuits before it died again?

Repeat bleeding the system and it started again and went a little further. This happened a few more times until it finally gave up the ghost and I didn‘t have enough battery power to crank the engine so gave up for another day.

My question is, would the system need bleeding multiple times or is it possible it’s pulling in more air on each run?

Is there anything else I should be looking for?

Many thanks in advance

 

[Hair Bear]

Drawing air in isn't unheard of but more likely to be fuel starvation. If the system is blocked somewhere it will appear to have air in it but is actually a lack of fuel.
You need to be methodical.
Make sure the breather on the fuel tank lid is clear. Then remove the outlet pipe at the bottom of the tank If it pours fuel out then replace it and move on. If not, there is likely a pencil filter in the tank above the outlet that is blocked. Unscrew the union and prepare to wear some diesel as you remove the union and filter. Clean and replace.
Next disconnect the outlet from the fuel pump. Give the prime lever several good goes to make sure it's ok. Reconnect.
Pull the fuel filters next and replace as necessary.
Bleed through and see what happens.

 

[Kidds]

What they said

 

[ant3000]

Thanks, I’ll work through those and check. The fuel was squirting from the bleed screws on the pump and when I had the 1st cylinder connected cranked off slightly but there would be the occasional change to the idle speed and then it would die out which I figure suggests the fuel is being starved. I just thought it was odd that it would seemingly run ok for a while and then die again at almost the same place in the field though?

 

[AlCapone]

What have you set valve clearance to??

 

[ant3000]

What have you set valve clearance to??

The chap before me had stripped the engine and changed the gasket. I’ve ran it a few times since and not had any need to work on the engine

 

[AlCapone]

I am thinking maybe it’s not fuel problem
For the previous owner to work on the engine suggests other faults

 

[Pad123]

I had a very similar issue with my b414, which I think maybe the same engine as the 434?

There’s a small gauze in the lift pump that gets clogged up. It’s easy enough to get at just one screw to undo. If you have a look in there and it’s that that’s clogged up I’d say that was your issue.

 

[ant3000]

I had a very similar issue with my b414, which I think maybe the same engine as the 434?

There’s a small gauze in the lift pump that gets clogged up. It’s easy enough to get at just one screw to undo. If you have a look in there and it’s that that’s clogged up I’d say that was your issue.

Yes, I think the B414 is pretty much the same engine as I watched a YouTube video of the B414 to get a better understanding of the bleed process. I’ll definitely check the gauze

 

[ant3000]

I am thinking maybe it’s not fuel problem
For the previous owner to work on the engine suggests other faults

The guy I bought from is a vintage tractor dealer (Bartletts of Winchester) and so I would hope to be confident in his work. As I mentioned it’s been running fine for sporadic use in the last few months and I’ve not had any concerns during that time.

The general opinion seems to be that I’ve stirred up some sediment in the tank but you think it might be something more insidious?

 

[AlCapone]

The guy I bought from is a vintage tractor dealer (Bartletts of Winchester) and so I would hope to be confident in his work. As I mentioned it’s been running fine for sporadic use in the last few months and I’ve not had any concerns during that time.

The general opinion seems to be that I’ve stirred up some sediment in the tank but you think it might be something more insidious?

Try cleaning fuel system first and see what happens

 

[ant3000]

I’ve checked the gauze and bled the system and the tractor is up and running however I just wanted to ask... the ’venting’ process mentions loosening the top venting screw on the pump and then working the lift pump lever until fuel starts to flow however I didn’t get much (if any) fuel flowing from this top vent screw (the bottom one did have fuel flowing though).

Is it usual to not get anything from this top vent screw? I’m guessing the top vent might have something to do with the fuel return?

 

[ant3000]

Top Vent Screw (A)

 

[Hair Bear]

Yay! So did you find a blockage anywhere?

 

[ant3000]

Yay! So did you find a blockage anywhere?

The gauze was a little bit dirty but nothing to shout about. There may have also been a bit of air that needed bleeding through too?