starter problem

wincbuck

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I have a Husqvarna LHT125 hydro riding mower with a 15.5 hp Briggs and Stratten engine. Using a fully charged 300 cranking amp battery the starter will engage the flywheel but will not rotate fast enough to start engine. I took the starter in to my local repair shop , they checked it out and said it was drawing too many amps and they sold me a "almost new" used starter. The same problem persists. All the connections are tight, no loose wires. I have had to use a power bank/booster to start engine. When it starts it runs great. Any help would be much appreciated.
 

willys55

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first..did you have the battery tested as well...you can be fully charged and still not deliver the rated amps printed on the battery. Also did you check the ground connection on the frame/engine? If it is corroded or loose, will cause a huge draw as well
 

bertsmobile1

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CHECK THE VALVE LASH
Too big a gap defeats the decompression.
The starter motors do not have enough power to overcome full compression so they turn over lumpy.
When turning slow each segment of the starter is energised for too long and gets too hot.
The hotter it gets the slower it turns
Eventually the insulation breaks down or the solder melts.
 

wincbuck

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CHECK THE VALVE LASH
Too big a gap defeats the decompression.
The starter motors do not have enough power to overcome full compression so they turn over lumpy.
When turning slow each segment of the starter is energised for too long and gets too hot.
The hotter it gets the slower it turns
Eventually the insulation breaks down or the solder melts.

OK Thanks for advice
 
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I think you have the overhead valves on that engine. Yes I agree with Bert set your valves 5 and 5 or the specs which is different than I said. You will have no more issues after that.
 

wincbuck

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So I adjusted the valve lash to .003", 1/4" past TDC. It will start with some hesitation cranking over. With spark plug out it turns over freely with starter. Would it make a difference to reduce valve lash further or may there be a problem elsewhere.
 

bertsmobile1

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Sounds like the cam is worn so the decompressor is not working.
Turning the engine over by hand slowly you should see the inlet open just before TDC then stay open all the way to BDC it will then stay closed till around 1/2 way back up when it opens a few thou then closes again.
This is done by a little bump in the cam which at speed the cam follower skips over.
Running too hot, old dirty oil , too little oil or just plain lots of hours causes wear on the cam & follower.
People make the mistake of replacing the cam but neglect the followers so the same problem comes back in a short time .
Not a difficult job apart from setting the end play in the crank which is done by different thickness sump gaskets ( PIA )
 
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I think 3 is a lil too tight. I go 4-4 or 5-5 on all my big engines such as 18 to 20 single cylinder models.

Try that and let us know ~!~!
 

wincbuck

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Many thanks to Bert and Boudreaux for your help. After trying several different valve clearance settings the problem persists. I think Bert hit the nail on the head suggesting that the cam may be worn as I seem to be missing that extra little bump open of the inlet on the way back up. I am still able to start the engine with the help of a booster/power pack 750 amp. Thanks again for your support.

winchesterbuck
 
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