Cranks once then stops.

Jonathan88

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Mower worked fine for the first while I had it every time I would go to start it it would crank slower and slower eventually not starting. So I charged the battery and it still wouldn't start, only cranking 1 turn or so. This made me think maybe the starter was getting weak so I changed it... still same results, 1 turn then stopping dead. So then I second guessed that maybe it actually was the battery and bought a new one and threw it in, still the same results. It's a 16hp 42in yardman.
 

Scrubcadet10

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Most likely the valves are out of adjustment making it hard to crank..
post the engine Model numbers so we can take a look at the engine, and/or get the valve specs.
 

ILENGINE

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Different mowers have different issues so please supply us with the model number of both the mower and the engine so we know what possible issue you could have.
 

seattlepioneer

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How 'bout checking the voltage at the starter motor and observe what happens when it cranks?

If it drops way down, you might have a poor electrical connection, bad solenoid or other issue.
 

Jonathan88

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Most likely the valves are out of adjustment making it hard to crank..
post the engine Model numbers so we can take a look at the engine, and/or get the valve specs.
Yes I have heard of this issue before wasnt wanting to commit to this quite yet... is that a big job?
 
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Scrubcadet10

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Yes I have heard of this issue before wasnt wanting to commit to this quite yet... is that a big job?
Requires removing the valve cover, and knowledge of how to use basic hand tools, and a feeler gauge set ,plenty of videos how to do it on the internet.
Intake Valve .003" - .005"
Exhaust Valve .005" - .007
 

seattlepioneer

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Requires removing the valve cover, and knowledge of how to use basic hand tools, and a feeler gauge set ,plenty of videos how to do it on the internet.

Well. I would consider it a big job and requiring possessing or developing significant skills.

I have viewed some of those videos of doing this kind of thing, and regard them as a cautionary tale I would prefer to avoid, myself. If I decided to do it, I might find an old mower to take apart and put back together for practice and to see if it would work when I got done with it.

One of the characteristics of being a DIYER should be expecting to have to do a task over two of three times until you figure out how to do the task competently. If I were to tear an engine apart when I hadn't done that kind of thing before, tearing apart another engine for practice and reassembling it and getting it to work might be an example of that.

I am, obviously, no Xpert on this kind of task.

Looking at this kind of repair would also lead me towards looking at other possible problems before diving into something complex like this.

For example, I already suggested checking the starting voltage at the starter to see is there might be a bad electrical connection causing the problem. I'd hate to undertake a complex repair only to discover that it didn't fix the problem, which was in fact something simpler which I had overlooked.

That is, in fact a common experience of mine as a DIYer.

The Xpert is distinguished by accurately diagnosing the problem first and then making one effective repair (most of the time, anyway). The DIYer is distinguished too often by a lot of guessing and supposing which leads to a lot of ineffective repairs.

I suggest that the smart move is to spend a lot of your time identifying possible causes of the problem and devising ways to test those guesses to see whether or not they are the actual problem.

Testing the voltage at the starter when cranking would be an example of that. A poor electrical connection could be causing poor voltage, and this can be tested relatively easily with a voltmeter. You could also measure the amps when cranking, which would give you an idea of how hard the starter is cranking, which might give you an idea of whether you have an engine problem that must be dealt with.

If you find that the cranking voltage drops way down you can look further to see what is causing that. If you have modest cranking amps, that suggests that the engine is OK. If the engine cranking amps are high, that might suggest an engine problem.

You could try those cranking tests with the spark plug removed and with it installed which might help you determine whether you have high cranking amps.

There are probably other possible problems which can be tested in similar ways, and I'd try all of those before tearing down an engine for the first time. If that's the only thing left on your list as a problem, then have at it and good luck!

I'm a humble DIYer. But I'd concentrate on finding things you can test before replacing parts or tearing down the engine. Guessing and supposing is not a scientific way to identify problems. Guessing at possible problems and then devising ways to test your theory to determine whether it's the actual problem -----that's the ticket I suggest!
 
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seattlepioneer

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Hmmmm! As I continue to think about this, I'm guessing that you could simply remove the spark plug and see if that caused the engine to crank normally. If it does, it would lend support to the suggestion that you have an engine problem. If the engine continues to labor with the spark plug removed, probably NOT that suggested engine problem. Wouldn't that be a simple, useful test to try before tearing apart the engine?

What other tests can you devise to help identify the actual problem rather than guessing and investing in making a repair which may not help?
 
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