GX 85 engine dies when jump pack removed.

tim2

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My neighbor has a GX85 mower, he told me that he has to jump start the mower everytime. He says that as soon as he removes the jumper cables the engine dies. The battery was just load tested and shows as a good battery, all the cables have been tested and cleaned. What or where should I start looking to find the problem?
 
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bertsmobile1

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Start by not ruling out anything.
The battery has nothing to do with the engine running unless it has a solenoid on the bottom of the carburettor.
The spark is generated by the magneto which is electrically indepedant on most engines unless it is a Kohler with electronic ignition advance .
So you start by checking there is 12V at the carb solenoid with the ignition turned on.
Then you veify they there is 12V at the starter solenoid
then you verify that 12V is getting to the ignition B terminal.
Where exactly does he put the jump start pack ?
and :welcome:
 

BlazNT

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This is a very interesting problem. You do not need a battery for an engine to run. the coil creates its own electricity (spark). I would think you have more than one problem. I would check all the ground(earth) connections. Including the connection the coil has with the engine. Meaning remove clean and replace. I would do this also with all ground connections.
 

reynoldston

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So you start by checking there is 12V at the carb solenoid with the ignition turned on.

:

I don't believe that model 85 John Deere has a carburetor solenoid that I ever seen ?
 

bertsmobile1

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You would know better than me.
However if they had Kohler engines with the SAM module they will not run without external power.
 

reynoldston

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John Deere in the 90's made these rear engine mowers at a cheaper price and put Briggs engines in them. Unless its something I don't know about? As said in a earlier post by BlazNT they run off a mag. Not going to get involved in this one.
 

tim2

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Well I got the problem figured out today. He said the battery tested good on a load test. It showed 13.21 volts but had no amps at all. I laughed my *%* off at him as he cut grass for thefirst time in the 10 years I have livedhere.
 
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