john deere 4230

kameron zabojnik · Jan 6, 2010

i have a 1974 john deere 4230 and when you rev the motor up past 1700 rpms it starts to miss and so i changed the fuel filter and that did not help so is it a bad injector or lift pump? thanks kameron

jared in wi · Jan 6, 2010

if it was a bad injector, it would miss all the time. are there any fuel leaks between the tank and the the injectors?? if so, it could be getting air in to the system. next, i would start by cracking injector lines one at a time to see if one it is on one particular cylinder or not. if the above things check out good, then i would start looking at the lift pump.

jared

kameron zabojnik · Jan 6, 2010

thanks i couldnt find any leaks but i also had a 4020 that had this same problem is there any way to test the lift pump

onefarmer · Jan 7, 2010

I had a problem with my 4430 like that and it was the fuel pickup in the bottom of the tank. A black slime had it plugged up. Looked like diesel algae residue. I drained the tank, pulled the fitting, flushed it with gas, put the fitting back in, put in 5gal diesel and added some biocide. I ran it around the yard to slosh it around in the bottom of the tank, then filled the rest of the way. No problems since.

Tx Jim · Jan 7, 2010

kameron zabojnik
How many hrs since valve clearance & inj pump timing has been checked? Have you tried any good fuel conditioner?

kameronz · Jan 7, 2010

i just set the valve clearnces and ill try so the fuel conditioner

TractormanNC · Jan 7, 2010

I'm with onefarmer on this one. Had exactly the same thing happen on a 4240.

rrlund · Jan 7, 2010

I'll second the lift pump answer. Does it start hard when it's warm? If so,DEFINATELY the lift pump. My 4040 did that.

john deere 4230

kameron zabojnik

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jared in wi

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kameron zabojnik

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onefarmer

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Tx Jim

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kameronz

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TractormanNC

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rrlund

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