John Deere mower won't prime

16 years ago

I have a John Deere JS63 walk behind mower 6.5 hp. The primer bulb does not seem to be sending gas. The mower will not start, but will run for a few seconds if I put gas directly into the primer bowl. My air filter needs to be replaced, but I don't know if that has anything to do with it. I have no idea how to fix a lawn mower, but I am trying to avoid the enormous bill I will get for having the dealer fix it. Thanks for helping.

Sort by:Oldest

Comments (8)

larryf
16 years ago
What are the numbers on the engine?

I believe this mower was equipped with a Briggs - but I am not sure if it was the flathead or overhead valve engine.

Most of the primer problems are related to a bad gasket between the air filter housing and the carburetor. The primer bulb is actually a small air pump that sends a shot of air to the carburetor float bowl. Air pressure in the float bowl forces a shot of fuel into the carburetor venturi area.

Since your engine starts on a prime - but does not continue running, I suspect there is an additional problem in the carburetor. Perhaps the main fuel jet is dirty or perhaps there is old fuel in the carburetor from last year.

Try giving the carburetor a little more prime to see if the engine will continue running. If the engine starts, replace the gasket between the carburetor and the air filter housing. Sometimes the plastic air filter housing warps and a gasket does not solve the air leak. Some techs use two gaskets. I usually replace the air filter housing.
baymee
16 years ago
Since your engine starts on a prime - but does not continue running, I suspect there is an additional problem in the carburetor. Perhaps the main fuel jet is dirty or perhaps there is old fuel in the carburetor from last year.

My response as well. Also, varnish in the carb, especially in the main jet of a Tecumseh carb, is the problem.
Related Discussions
John Deere weed eater won't crank
Q
Comments (1)
I have one of these (also a John Deere) about the same age. Mine would not start no matter what I did, it had both spark and fuel. It finally started running when I took off the muffler and cleaned out the spark arrester screen with compressed air. I've had several small two-stoke engines fail to start and run because the spark arrester was plugged.
...See More
John Deere RX 75 won't crank
Q
Comments (1)
Could be one or more interlocks. My first choice would be the ignition switch (key). Sounds like intermittent contact. Second choice would be the solenoid. Do you know how to jump the solenoid? This would help you focus on whether either part is the culprit. To jump the solenoid, you need to put +12v to the third wire (the smaller connection). Solenoid should click and start cranking motor.
...See More
John Deere cranks nicely but won't start.
Q
Comments (13)
Kawasaki FB460V engine. A free PDF manual for the engine can be obtained at "my mower parts dot com" (but translate that into a genuine URL to get there). OP still has not confirmed if this tractor has a electric PTO clutch but some internet searching indicates it likely does. While it is not typical for a BELT DRIVEN blade drive system to result in shearing or bending of a flywheel key it is certainly possible that in this particular case (lift arm disengaged and dropped deck assy) the stopping of the blade belt was abrupt enough to shear or bend the flywheel key. Usually a belt driven blade system (and thus the engine crankshaft) will not stop turning quickly enough when the blades encounter a significant foreign object to cause shearing of the flywheel key. The saving grace in belt drive systems is that the belt usually slips enough that the inertia of the engine is absorbed relatively slowly......and the key survives intact. However.....in the case of the deck being dropped downward suddenly by the lift link letting go......the belt would have been given an added bit of tension (by dropping too far down) and that just might have been enough to shear the flywheel key.
...See More
John Deere LA140 Stalls After 2 Hours, Now Won't Start.
Q
Comments (2)
Well might start by posting the engine model number. Walt Conner
...See More
jerry880
Original Author
16 years ago
Thank you very much. I just joined this site and it seems there a lot of people willing to help the less mechanically inclined like myself. Thanks again.
bill_kapaun
16 years ago
It appears that is a Briggs engine with the bowl type carb.
Remove the "Brass Nut" that holds the carb bowl on. THAT is your Main Jet. Clean out the hole(s) with a fine wire, like you would find on the tie for a loaf of bread.

You'll probably want to clamp off the fuel line first.
You may also want to "flush" the line for a couple seconds with the bowl off.
paulgill123
15 years ago
I have a John Deere JS63 6.5 engine walk behind lawn mower. It will not start at all and it has been parked in my garage for over 2 years. I was wondering if that has anything to do with it. If someone knows a solution to this problem it would be really helpful. Thanks.
sirwired
15 years ago
Yes, a mower that has been sitting idle for two years almost certainly has a plugged carb. Drain and properly dispose of all the fuel, clean the jet hole built into the "nut", and see if that helps.
lynn_ogard_gmail_com
12 years ago
I just bought a really nice John Deere push mower off Craig's list. The seller started it for me and when I got home I started it and mowed. Here comes the embarrassing part. I forgot what I did and since I can't get it to start. On the handle it has a throttle towards me a turtle and push away a rabbit. Must have a choke and you pull a lever and hold with thehandle when you pull the rope to start. I have pushed lever all the way to rabbit and pulled, then turtle and either way - nothing. I know the mower is good.
I am definitely doing something wrong. Couldn't be that tricky. Any help? Much appreciated
lynn_ogard_gmail_com
12 years ago
I just bought a really nice John Deere push mower off Craig's list. The seller started it for me and when I got home I started it and mowed. Here comes the embarrassing part. I forgot what I did and since I can't get it to start. On the handle it has a throttle towards me a turtle and push away a rabbit. Must have a choke and you pull a lever and hold with thehandle when you pull the rope to start. I have pushed lever all the way to rabbit and pulled, then turtle and either way - nothing. I know the mower is good.
I am definitely doing something wrong. Couldn't be that tricky. Any help? Much appreciated