# John Deere 4020 starting problem



## Oetkenj (6 mo ago)

I converted 4020 over to 12 volt system and the only thing I connected was for the alternator to charge the batteries. I use a push button start and no lights and any electrical stuff is connected. The problem I have is if the tractor sits for a couple weeks and you go to start it it fires up no problem but if it runs for about 10-15 minutes and come back an hour later it will not turn over enough to start and it’s very hard to get it to jump start it also. But the funny thing is when you come back a week or so it fires right up.


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## Tx Jim (Jul 28, 2020)

Welcome to MTF
You should ask moderator to move your thread from lawnmower to big tractor section. John Deere

Your no start problem sounds typical for the closed center hyd system such as 4020 has is having an internal leak causing frt hyd ump to attempt to pump oil while engine crankshaft is being rotated to start engine. Hyd pump trying to pump puts more strain on starter. There are 3 solutions. Use manual hyd p[ump destroking screw or higher priced electric destroking screw OR vigorously turn steering wheel from side to side while engaging starter with push-button.


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## BinVa (Sep 21, 2020)

Although I agreed w/TxJim…Hard starting while warm or having to wait to start is characteristic of a closed hydraulic system. I differ on the actual cause of the hard starting. I have found on my 20 and 30 series tractors, the problem/remedy is electrical. Load test your batteries, amp test the starter under load, and do a voltage drop test on the battery cables, a gear reduction starter will also help. Your problem is one of these 3 things…my money is on the cables or starter internals. B.


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## linleeridge35 (Aug 11, 2021)

Totally agree with TXJim. Had this happen many times on 3020, 4020, 400A backhoe, 2140, etc. Rocking the steering left/right quickly while cranking usually solves the problem. The settings on the closed center hydraulic pump need adjusting for a start.


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