McCormick IH 434 starting problem

darrylh

Member
Hi Guys,
My second post on the site with my newly acquired tractor. looking for some pointers following an engine rebuild and engine starting issues.

I have dispensed with the old style glow plugs and installed 12V ones. I have bled fuel firstly to bottom bleeder on CAV pump (fuel gushes out when screw is open), then undone all the 3/4" unions on the injectors themselves (fuel squirts repeatedly on all injectors when attempting start up), so this all looks good.

I get smoke, and progressively more smoke when cranking, but after say a good 30 seconds of cranking, engine fires up BUT immediately cuts outs. No re-start right away but after a while it will fire again but immediately cut out.

How about a 1,2,3 on what to check next from the experts, please.

Other points to note. I am happy timing wheels are all matching. The mark on the CAV pump mounting aligns with the bottom of the 2 lines on the engine casing. I cannot seem to move this easily (in neutral) as seems very tight. Is it likely this matters, as long as the pump line is somewhere between the 2 engine case lines? Also new lift pump just installed.

Thanks
Darryl
 

Mur Huwcun

Member
Livestock Farmer
Location
North West Wales
You may well need to keep the glow plugs on for a few seconds after startup to get her going. Is this a first startup after a rebuild or a long term lay up?
 

darrylh

Member
Yes, have kept the plugs on after start. This is first start up after the rebuild. . Note starts after much cranking, runs for a couple of seconds then cuts out, never re-starts after, but will start again a little later......but exactly the same each time.
 

Wisconsonian

Member
Trade
Check the fuel return to the tank. I don't know about a CAV, but other rotary pumps will shut off with the return blocked. Otherwise, check the fuel supply when it dies, is the pressure still there if you crack a bleeder right away? does it have a primer pump to check the pressure that way?
 

Mur Huwcun

Member
Livestock Farmer
Location
North West Wales
I’ve never had much success with startups on these after rebuilds although the rotary pump ones are much better than the inline versions without a tow or extra heat. Try a blowlamp or heatgun into inlet manifold to save overusing the glowplugs just to get it going once, things start to bed in afterwards. I’ve a 275 that starts no problem now but was a pig after new sleeves and pistons and used a heatgun on it. I didn’t touch the head, injectors or pump on that one though, too much of a tight a**e 😂😂😂😂
 

Kidds

Member
Horticulture
Any particular one? And then?
Leave the one easiest to get to, then you only have one squirting fuel out and the others should be getting full flow, when it starts do up the last one.
That's how I always do it, it might not solve your issues but it sounds like you have all of them slack.
 

Mur Huwcun

Member
Livestock Farmer
Location
North West Wales
Leave the one easiest to get to, then you only have one squirting fuel out and the others should be getting full flow, when it starts do up the last one.
That's how I always do it, it might not solve your issues but it sounds like you have all of them slack.
It’s the way to do a rotary pump as a rotary only has one piston therefore one outlet will rid all the air. An inline pump will need a few open though.
 

darrylh

Member
I undid injector nut nearest fan and tried a start. I got fuel squirting out every second or two, but did not get a start (did up nut).

I am adamant that timing is right and my son said he checked it also (and he has a photographic memory), but I want to take all off again and check (although it is a right pain in the ar*e to check it). Have read some talk about timing being 180* out. We noticed during rebuild some timing wheels are not aligned with marks when turned around 180*, but does it matter where these marks are on first start??
Similarly, is it vital (or best chance) to get cyl 1 TDC. We are trying with 2 batteries daisy-chained to get a start. We may get 1 fire (or 2 if we are lucky) before both batteries are exhausted. Then we try another day when re-charged.

Fuel pump marks are now smack bang in the middle of the engine case marks.

Can't believe we are having this trouble, given we have all new parts and all has gone back as before - what could possibly go wrong anyway (we took phone photos before we started).

Does this problem ring a bell with anyone, as to what the problem might be??? (in particular starting after an engine rebuild???)

Will try the blowlamp when the batteries re-charge, but will probably be another day.

Tony, I could get a tow organised with a neighbour (very much my planB) but read on the forum someone towed their 434 a 1/2 mile and it still would not go. What do you think?

Wish I had left the thing black-smoking as before - but thought a rebuild would be only a good thing to do:mad:
 

Sunbeam Alpine

Member
Trade
It could be worth trying to pressurise (lightly!) the fuel tank to assist in getting fuel through. I do this by wrapping a rag round an air gun from the compressor to create a seal.

I have a couple of old machines without working fuel gauges, and they run out of fuel a couple of times a year. I use the pressure method as it works quicker and I can never find the right spanner when I need it!
 

Andy Nash

Member
It is a CAV rotary pump isn’t it?
what about the top bleed screw in the pump - have you bled that?
You need to crank the engine with the screw open to do that.
There should be lots of white smoke when it’s bled properly, not just a bit.
The timing marks on the gears don’t align themselves every revolution on these.
You can check whether you’re 180 degrees out by removing an injector or the valve cover.
 
The timing marks should all line up, the gear tooth with 1 center punch mark, fits in between the 2 punch marks on gearit meshes with,
If the engine has been turned over before injector pump is fitted, then marks on pump gear, even if meshed up right could well be out, this is due to the different sizes of gears, ie, take the timing cover off and check it,
If you can be bothered after timing it up correctly, you will have to turn it over 24 times before timing marks line up again, for this reason it needs to be checked again,
Yes pump can be 180 out on some tractors, on a Nash, as the dowl will only let you fit the gear one way, so pump turns half speed of crank, so maybe 180 out, take inspection cover off the side of pump, and rota will be marked, A,B,C,D,E,F,G, I think it should be on E, but someone can correct me on this,
However thinking about it, if its 180 out, it would never get any compression on injection stroke for it to fire, as exhaust valve will be open as the piston is coming up to injection point, to check this, remove rocker cover, and both inlet and exhaust valve should be closed on the cylinder it squirts fuel out of injector pipe
 

AHDB winding down horticulture and potatoes operations as Ministerial decision awaited

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AHDB has announced yesterday it is winding down significant activities on behalf of the horticulture and potatoes sectors.

While still awaiting a decision on the future by Ministers in England, Scotland and Wales, AHDB wants to reassure levy payers their views have been heard following recent ballots in the two sectors.

AHDB is now stopping programmes of work that could be restarted in the future by grower associations, individual growers or the supply chain. This work includes for example, export market access and promotional international trade event work, consumer marketing campaigns and market pricing and insight information. AHDB will continue to deliver limited emergency work on pests and diseases, including the Extension of Authorisation for Minor Use (EAMU)’s and some...
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