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  #1  
Old 09-25-2012, 05:07 PM
BryanStein BryanStein is offline
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John Deere 757 Kawasaki 25HP starting problem

After reading for a month or two this is my first post here. This problem has got me really dumbfounded .... and I'm usually pretty good at sorting these things out.

Bought used JD 757, 2006 model about a month ago. Motor is the Kawasaki 25 HP FH721D motor. Rebuilt motor, new pump, new clutch, new other stuff. This mower had been sitting a while with 900 hrs on it. It appeared to have been abused before getting rebuilt.

Ran it for an hour cutting the grass and parked it. It ran great but I noticed the altenator light was on when the clutch was engaged at operating speed. It was off if the clutch was not engaged. Concluded the voltage regulator or stator was not pumping enough current.

Went to measure the AC current output of hte stator and notice the plastic electrical conection to the VR was slightly melted. Didn't know if that was before or after the rebuild. Measured the voltage output from the stator and it was 32 volts AC. Specs I had said 26 volts, but JD Mechanic said 32 was about normal. Well the wiring harnes was fried so I replaced Stator and VR. Also replaced the coils while I was at it (they looked bad).

Pulled the engine, to make the repairs and reinstalled the engine. Go to crank it up and it cranks fine at idle. Back it out of the garage and rev it up and it goes dead quick. Try to restart and it just won't start.

Checked spark fire while cranking, and they fire. Checked fuel pump output while craking and it pushes fuel.

I saw the choke linkage was off and concluded the choke valve wasn't choking. Fixed the choke linkage and it still won't crank when idle or when at full throttle.

Pull breather and poured some gas in carburator. It cranked and reved up nicely until the gas ran out.

Checked the fuel solenoid and it is clicking. I'm getting 12.6 volts to it. I will pull it tonight to see make sure the clicking is indeed moving the solenoid. I'm confident it is. IT RAN GREAT two week ago. When I try and start it, there is no change to the pitch of the engine when I choke it.

Its pretty obvious its not getting fuel. However, it ran great before I put the stator on it. Can a carburator get clogged in a week just by tilting from side to side while removing the engine? What else could it be?

Another thing that may be ok but I thought it strange. When the throttle moves from idle to full, nothing on the carburator moves. It move the control assembly on top of the govenor assembly, but does not open (or does it close when accelerated) the throttle valve at the carb. Is this normal? I'm speculating the throttle valve opens by the force of the air flow accross it. I didn't touch the carburator when I rebuilt the electrical system.

I did have to drill out a broken bolt that mounts the fuel pump. I had to disconnect the fuel pump. Its possible I got some small shavings in the fuel pump, but unlikely.

HELP!!
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  #2  
Old 09-25-2012, 05:31 PM
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Restrorob Restrorob is offline
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If there was any trash in the carb float bowl it's likely clogging the main jet after tipping the engine around, Defiantly sounds fuel related so a carb clean would likely solve the issue......
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Old 09-25-2012, 06:20 PM
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Sharpcut 1 Sharpcut 1 is offline
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I know this is pretty elemantary, but did you turn the fuel valve back on, or is it possible fuel filter is partially plugged and debris got dislodged when removing/ installing engine?? Unhook fuel line at fuel pump to see if you have flow. Do you have internally or externally vented carb?? If external and vent to atmasphere is blocked, will not get fuel. Did you hook signal line for fuel pump back to block?? Ground on carb??
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Old 09-25-2012, 11:17 PM
BryanStein BryanStein is offline
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No fuel valve. Plenty of fuel from fuel line when I disconnect it at the carburetor and try and crank. External vent. The vent pipe is clear. It could be clogged within the carb. How do I check that?

There is no signal line from fuel pump. Carb is not nitty grounded. There is no need to ground three carb b we cause the fuel solenoid had a ground wire and a live write. Fuel solenoid "clicks" when switch is turned. Measures 12.6 volts at solenoid.

When I have had to rebuild carbs before it was because it would not idle or would not run smooth at speed. This is usually a sign of clogged jets, but still getting enough fuel to try and run. This thing won't even think about cranking. Thus, fuel is not getting to either the low speed jets or the high speed jets. Its not likely that all 4 jets are completely plugged at the same time. This points me back to the solenoid.

My problem is why would it suddenly stop working and get 100% clogged. I guess there could be trash plugging the main solinoid orifice, but that's a BIG opening. I'll check it tomorrow.

Anybody got any other ideas or have seen this before? How do I check the internal vent on the carb?

Thanks
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Old 09-26-2012, 06:58 AM
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Quote:
Originally Posted by BryanStein View Post
Anybody got any other ideas or have seen this before? How do I check the internal vent on the carb?
Seen this many many many times, Ah....That's why I suggested a carb clean, That will clean the vent as well......
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"Why go out preserved when you can go out beat up, worn out, sliding in sideways screaming, Holy Sh!t What A Ride" !!!
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Old 09-29-2012, 11:44 PM
BryanStein BryanStein is offline
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Quote:
Originally Posted by Restrorob View Post
Seen this many many many times, Ah....That's why I suggested a carb clean, That will clean the vent as well......
Float valve was stuck shut. Removed carb. It was clean. Don't know why valve was stuck. No trash or debris. First time I've had a float valve stuck shut with no warning after running great.

Thanks for all the replies.

Now I just need a writing diagram because its not charging and the stator wires get real hot.


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Old 09-30-2012, 08:28 AM
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Also.....


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You never learn anything until you admit you don't know it all...
Quote:
Originally Posted by MannsLawnService View Post
some times the man in my mirror isn't so smart...
"Why go out preserved when you can go out beat up, worn out, sliding in sideways screaming, Holy Sh!t What A Ride" !!!
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  #8  
Old 09-30-2012, 10:10 AM
BryanStein BryanStein is offline
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Restrorob, thanks for the tons of info.

Because this is not similar to the carburator problem, I will start a new thread. Please reply there
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