4020D sputters when cold

[Ted K]

Lately my "65 4020D, after being plugged in for 2-3 hours, will start immediately but will miss occasionally until it is throttled up to about 1000rpm where it runs real smooth. After it warms up to operating temperature it runs fine anywhere above 900rpm and pulls strong and yesterday I worked it hard on the grinder/mixer and it never missed at all when pulling. But if dropped down to 800rpm idle it has an occasional miss. Any ideas before I begin taking things apart? I had to put a new lift pump in last summer so I should be able to rule that out. (Should be able to!) Thanks.
Ted K

 

[LJD]

If it was mine - I'd leave it alone until it got worse. Sounds like a minor issue. I'd suspect the injectors are a little worn and not working perfectly under low flow at low RPMs.

Your 4020 has a "distributor" injection pump with just one little central high-pressure pump that serves all six cylinders. So, it's rare for a pump to have a problem and not effect all six cylinders equally.

I can't hear it so don't know if the skip seems to be on specific cylinders - or general to all.
An overall skip or "flutter" when cold that gets better warm is often caused by the timing being a little retarded. Have you tried bumping it up a few degrees?

 

[Tx Jim]

I agree with LJD. It's not broke enough to warrant repair if it were my tractor IE similar to old saying "if it ain't broke don't fix it".

 

[rick deere]

posssible dirty fuil filters

 

[Ted K]

Fuel filters were changed when I changed the transfer pump.

I"ll check the timing and if that"s OK then I will have the injectors checked.

Thanks for the advice.

Ted

 

[60jds]

we got one that does the same thing its been like that since we rebuilt the pump on it. it only does it when its below 40 degrees really tractor runs good but the reason that ours does it is the screw is all the way in as far it is safe to plow with on the pump.

 

[WJD]

This may sound too simple but how old is your fuel? Fuel does not like being stored for months and months anymore. It just sounds like incomplete combustion at low engine speeds.

 

[Matt NWIN]

My 4010 has done that since the day I bought it...nearly 20 years ago. Hot or cold, doesn't make a difference. Runs fine, plenty of power, no smoke at anything above 1000 rpm. Previous owner told me it had done since they had bought it, in the 1970's. Like the others say, not broke enough to mess with....

 

[Ted K]

The fuel is some I bought last summer, hadn"t thought of that possibility.