# Hard starting engine



## Kgiffin (3 mo ago)

Have a John Deere 4039 4 cylinder diesel hard to start. Just serviced engine, new air filter, fresh oil and filter, new fuel filter, lines bled. Still won’t start without using either. What should I do next?


----------



## Fedup (Feb 25, 2014)

Kgiffin said:


> Have a John Deere 4039 4 cylinder diesel hard to start. Just serviced engine, new air filter, fresh oil and filter, new fuel filter, lines bled. Still won’t start without using either. What should I do next?


4039. That leaves a few doors open.

In a tractor or an industrial engine? Type/make of injection pump? Maybe some history on what it does, how it runs (when it runs that is), overall condition, a "guesstimate" on hours of operation, new problem/always been that way, what may have been done to it lately (other than a new fuel filter), that sort of thing..

Kind of hard to guess at what "might" be wrong with what little you provide.


----------



## thepumpguysc (Jan 25, 2015)

It looks as though it has a hand primer on the supply/lift pump.. TRY pumping the hand primer before turning the key.


----------



## Tx Jim (Jul 28, 2020)

Kgiffin said:


> Have a John Deere 4039 4 cylinder diesel hard to start. Just serviced engine, new air filter, fresh oil and filter, new fuel filter, lines bled. Still won’t start without using either. What should I do next?


I suggest you diligently look for a solution. JD 300 series engines such as your 4039 don't tolerate ""starting fluid"" very well & you'll end up needing to install new pistons/rings if you're not very careful. 

I agree with others that you need to check to determine if fuel is bleeding back to fuel tank & manually pump fuel to inj pump before attempting to start engine.


----------



## Kgiffin (3 mo ago)

Kgiffin said:


> Have a John Deere 4039 4 cylinder diesel hard to start. Just serviced engine, new air filter, fresh oil and filter, new fuel filter, lines bled. Still won’t start without using either. What should I do next?


The injector pump is a stanadyne pump. The engine is used as a farm power unit to grind feed and fill silo. I have no idea how many hours the engine has on it. Same owner for the last 7 years with very little maintenance on the unit. Used to start any time without either but has had issues for the last year. Only gets used one a month or so to grind feed and once a year to fill silo. When the engine starts it surges for a short time then smoothed out. The fuel filter remains full the best I can tell. Will look for the manual pump tonight and try pumping as it is turned over and get back with you.


----------



## Kgiffin (3 mo ago)

Kgiffin said:


> The injector pump is a stanadyne pump. The engine is used as a farm power unit to grind feed and fill silo. I have no idea how many hours the engine has on it. Same owner for the last 7 years with very little maintenance on the unit. Used to start any time without either but has had issues for the last year. Only gets used one a month or so to grind feed and once a year to fill silo. When the engine starts it surges for a short time then smoothed out. The fuel filter remains full the best I can tell. Will look for the manual pump tonight and try pumping as it is turned over and get back with you.


Found the manual pump, it pumps good 10 to 12 times and then it stops. I was able to get all the air out of the fuel filter but was not able to get fuel pumped to to the injector pump. Does this indicate the fuel pump is bad?


----------



## thepumpguysc (Jan 25, 2015)

Loosen the fuel INLET line on the inj pump and let the air out..
wait until you get solid fuel and no air and tighten it back up..
Next, loosed the lines AT THE INJECTORS a couple of turns and crank the engine.. wait till fuel squirts out and tighten them up..
It should start now..


----------



## Kgiffin (3 mo ago)

thepumpguysc said:


> Loosen the fuel INLET line on the inj pump and let the air out..
> wait until you get solid fuel and no air and tighten it back up..
> Next, loosed the lines AT THE INJECTORS a couple of turns and crank the engine.. wait till fuel squirts out and tighten them up..
> It should start now..


We primed that way after we changed the filter and it started fine. The next day it would not start. Tonight I was unable to get fuel to the injection pump with the hand pump. It would pump 10 to 12 times and if stopped pumping. If you waited five minutes it will pump again and stops pumping again. Does that indicate a bad fuel pump? Or a bad fuel hose?


----------



## dvcochran (Nov 23, 2010)

Kgiffin said:


> The injector pump is a stanadyne pump. The engine is used as a farm power unit to grind feed and fill silo. I have no idea how many hours the engine has on it. Same owner for the last 7 years with very little maintenance on the unit. Used to start any time without either but has had issues for the last year. Only gets used one a month or so to grind feed and once a year to fill silo. When the engine starts it surges for a short time then smoothed out. The fuel filter remains full the best I can tell. Will look for the manual pump tonight and try pumping as it is turned over and get back with you.


Good, strong batteries? I have a JD2640 with a 4-cylinder and you can forget starting it unless the batteries are good.


----------



## Busted Tractor (May 22, 2018)

A diesel needs a few things to start. 
1.Compression: compression makes heat, heat is what lights the fuel.
2 Atomized fuel: The fuel needs to be atomized for proper combustion, dribbles or squirts from the lnjectors don't light off very well.
3. Timing: Fuel needs to be injected at just the right moment to get the best ignition.
4. Proper pressure from the injection pump to push the fuel thru the injectors
5. Good batteries: without proper cranking compression, proper pressure from the injection pump 
Having worked as a mechanic for too long here are my troubleshooting tips
1. Listen to the engine as it cranks -- does it crank even, or does it seem to have easy spots where it seems to speed up and slow down. -- Repair engine
2. Do you have white smoke when it won't start? -- Repair engine and/or service injectors
3 No smoke but if you crack and injection line at the injector you have fuel. --- Battery, starter, cable connections, or time to repair the injection pump
4 No smoke but air if you crack the injection lines at the injector ---- You need to find and repair the leak in the fuel system or repair/replace the lift pump (if it has one)


----------



## Qcumber guy (Jun 25, 2017)

Back to Basics before guess games starts
Check fuel level
Check fuel valve at tank for free flow
Then go down the line and check free flow of fuel at every connection and remove air as you go along, then make sure all fittings good hand tight.....


----------



## Kermit541 (3 mo ago)

It appears that the supply pump has hand priming. Before turning the key, try pumping the hand primer.


----------

