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Weak spark on Pressure Washer


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06-06-09, 02:09 PM   #1  
Weak spark on Pressure Washer

I have a Craftsman 6.75hp Pressure Washer, model # 580.752700. Went to use it and found it hard to turn over. Could hardly pull the cord out. I pulled it apart and checked the flywheel and key. The key was undamaged, but the flywheel was heavily corroded. I shined it up with some 320 sand paper. I discovered there is a grove in the flywheel. Not a big one, nor does it go all the way around, but probably 1/3 of the way. I pulled the armature off to see if it was damaged, it wasn't. Would that groove cause a weak spark?

ALSO, When I went to reset the armature I found there were no specs in the manual. I got out a couple of my small (Briggs and Stratton) repair manuals and looked. One is a Chilton, the other put out by Briggs. They have conflicting information as to the gap spacing. One said .004 and the other said between .010 and .014. That's a big difference.
Can anybody help me out here? I set it to .005 but have a very weak apart. It pulls freely now, but won't start.

Yes, I put in fresh gas, even bought a new air filter and plug. The air filter I had was really dirty so I took it out and pulled it over without it in. With it out it sort of 1/2 fired. I thought the filter was the problem, but have a clue now.

 
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06-06-09, 05:47 PM   #2  
No, the groove isn't the problem... You said it had ""Heavy Corrosion"" on the flywheel??? Has this unit sat outside in the weather??? Try it with the kill wire disconnected from the coil.. When you say ""Weak Spark"" is it intermittent, or wont jump a '030 gap??? Will it fire with a shot of fuel in the plug hole?? Just wondering as the corrosion on the flywheel makes me wonder about the inside condition of the carb??? The flywheel to coil gap should be 010" but if you post the engine #s the pro's will look into it,,,, Roger


Last edited by hopkinsr2; 06-06-09 at 05:53 PM. Reason: more info
 
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06-07-09, 07:03 AM   #3  
Being a pressure washer I thought the heavy corrosion could be due to back spray while washing the house.

The model number is 580.752700. Can't find that number in any of the manuals I have. Going to the Briggs web site right now to see what I can find.
When I tried the shot of fuel in the plug hole it fired back through the carburetor??
One of the manuals says the valves and piston head should be cleaned every 100 hours of use to remove any carbon build up . I've never cleaner them, could that be my problem?
I'll reset the armature gap to 10 and see if that helps. Getting tired of pulling this thing apart, got a 2 story house to wash

 
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06-07-09, 04:51 PM   #4  
You gave us the model of the pressure washer.. The engine #' should be around the spark plug somewhere & state Model, Type & Code for a briggs..I wouldn't think carbon is a problem but a backfire thru the carb??? What is the compression?? Sticking valve maybee???? Roger

 
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06-07-09, 05:30 PM   #5  
These numbers were stamped on a plate above the muffler?
129602-0113-E1-040224FB
I pulled the head, oh yeah I had carbon alright. Got that mess cleaned up, cleaned and reset the valves, put t back together and now I have no spark at all. The compression is good. I don't have a meter to check it with, but I stuck my finger in the plug hole and pulled it over, seems fine.

With the weak spark am I looking at buying a new armature-magneto?? I just priced one out, right around $40.

You mentioned the carb possibly being a problem too. It's mostly plastic I hate messing with that. I've never touched one that ran right afterward

 
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06-07-09, 05:56 PM   #6  
Make sure you have the plug against a clean piece of metal to test the spark. Double check the kill wire isn't grounding out and check for spark with the wire disconnected form the coil.

I'm gonna say the magnet would be a last resort...they are known to go bad but very unlikely, I would make sure the coil isn't faulty before the magnet.

 
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06-08-09, 08:02 AM   #7  
I changed the coil this morning, in the process of resetting the valves right now. I can't seem to find the specs for this engine anywhere.
Example: I need to know the torque for the head bolts, can't find it. Need to know the specs for the valves too. 1 book says between 2 to 4 & 5 to7. My Chilton book says 5-7 & 9-11.
I e-mailed Briggs and Stratton but it could take up to 3 days for them to get around to answering it.
I spent the whole weekend pulling this thing apart and putting it back together again. The magnet has to be good, it snatches anything metal that gets near it.

 
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