# John Deere 170 backfiring when attempting to start



## 2cyclefanatic (Apr 22, 2011)

havent posted in awhile, but my lawnboy works like brand new 

of course, its fall, but now my JD's acting up AGAIN :fail:

i went to start it a couple weeks ago to keep the batery charged, and nearly had a panic attack because the stupid thing _BACKFIRED (and i dont mean a little "pop- i'm talking about a "BANG!"- almost like a gunshot) before finally starting. its not the first time it's done this-but i'm worried that if it keeps acting like this i'm going to end up putting a hole in the engine block-or worse,it'll screw the timing up. it did it last season as well-even when it was 70 degrees-so it's not the first time this has happened. 

engine: Kawasaki FC420V-DS-001

replaced: carbureator, spark ignitor, ignition coil, spark plug, air filter, oil change (SAE10W30), fuel pump (off a FC540V-that might be the problem, but it works fine), fuel lines.

any help is appreciated  i can't afford to get a new tractor, and i don't have any room for anything else, so hopefully i can figure out what's going on befor the engine finally dies_


----------



## small engine (Oct 14, 2010)

Your valve timing is probally off , i would also check the adjustment on the valves


----------



## Maytag (Dec 10, 2007)

I'm putting my bet on a partially sheared flywheel key, and/or loose flywheel. I would also believe a sticking valve.
Just my $0.015 worth. (recession you know).
Good Luck
>Maytag -(not a mechanic but I do have a shed full of running, self-repaired machines)


----------



## 2cyclefanatic (Apr 22, 2011)

idk

i'm going to have dad look at it when he has a free moment


----------



## 2cyclefanatic (Apr 22, 2011)

well..........long story short-apparently the valve was cracked or worn as it had NO compression whatsoever, and since i hardly used the thing anyway, we sold it.


----------

