Timecutter MX 5060 - Cranking Problem

Bigfoot100

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Toro Timecutter MX 5060
Model Number - 74641
Serial Number - 313003271
Kawasaki FR691V

Hello - I bought this mower slightly used a few years ago, and it runs and mows beautifully. However, I have a very frustrating problem with starting it. Most of the time when I turn the key (with the control levers out to engage the brake, PTO off, etc.), I will hear a click and the engine will turn just a little bit (maybe a quarter turn) and stop. Sometimes there is a whining sound if I hold the key in the starting position, but no more movement. Sometimes I will hold the key in the starting position and after a second or two the engine will start cranking again and start. Other times it won't. Sometimes I turn the key back after the initial partial turn and then turn it to the starting position again, and it will start cranking and start. But oftentimes it will just not crank after that initial partial turn. I keep playing with the key until eventually I get the engine to crank and start, but sometimes it takes a while and feels like I'll never get it started. I have a fully charged jumper battery that I connect from time to time to see if maybe my battery is dying, but that doesn't help. I've even jumped with a car, and no difference.

Does anyone have any ideas for where to start troubleshooting? I have a multimeter and am comfortable poking around electrical systems, but would really appreciate some advice. I've never troubleshot a system like this.

Thanks!
 

bertsmobile1

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That is the typical symptoms of excessive valve lash over riding the automatic decompression .
Usual test is to remove the spark plugs and see if the engine cranks normally , should be a fair bit faster .
Watch the plug holes ( 2nd person is an advantage here ) if liquid fuel spurs out then you farb float needle is not shutting off the fuel and the carb needs a little TLC .
 

Bigfoot100

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Awesome, thanks bertsmobile1. I will check that. I've never adjusted valves before, but I'm sure there's a youtube video for that out there.
 

bertsmobile1

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The Kawasaki manual is available from K & C Mower parts web page ( no link I am on a different computer ).
They are an eccentric pivot type adjustment so the trick is to just loosen the lock nut enough to be able to turn the bolt against a bit of resistance.
Note the lock nut is a 1/2 nut so no gorilla strength tightening required
Also check the bolt under the rocker mount that holds it in , they do tend to come loose on some engines .
 

Bigfoot100

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Wow, very helpful! Thanks again, and I will report back.
 

Bigfoot100

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Ok, pulled the spark plugs and found that the engine turned just fine when I turned the key. So I adjusted the valves per this video:


I used a .004" feeler gauge, just as shown in the video. I also replaced the gaskets on both sides when I closed everything back up. The first time I turned the key, the engine turned normally, so I was pretty excited. But the next time I turned the key, I was right back where I've been - only some slight movement and sometimes a whining noise.

Any ideas? Is there a chance that .004" is not correct for my serial number...? I don't have the service manual.
 

Scrubcadet10

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I had that problem with my cub 2 years ago, valves checked fine, ACR was working, battery tested good, replaced the starter solenoid... Fixed.
 

Bigfoot100

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Sounds like it's worth a try, thanks. Before I do that, I'm wondering if there's a way to confirm that the automatic decompression is working?
 

Bigfoot100

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Ok, I just found a service manual for this engine online, and it clearly indicates that the valve clearance should be 0.05 ∼ 0.10 mm (0.0020 ∼ 0.0039 in.). Not sure where the 0.004" in the video came from, but I'm going to open things back up and adjust to 0.002" and see how it behaves.
 

bertsmobile1

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Ok, I just found a service manual for this engine online, and it clearly indicates that the valve clearance should be 0.05 ∼ 0.10 mm (0.0020 ∼ 0.0039 in.). Not sure where the 0.004" in the video came from, but I'm going to open things back up and adjust to 0.002" and see how it behaves.

Put that calculator away .
Most micrometers are +/- 0.0005 " so if you think you can measure the difference between 0.0039" and 0.004" using feeler gauges you are living in cloud lar lar land .
The accepted precision when using feelers is +/- 0.001" , as shown by the spec which is actually 0.003" +/- .001"
The actual precision when using feeler gauges in closer to +/- 0.002"
If you give 100 mechanics a set of feelers and ask them the set a gap, then measure it very accurately you will end up with 100 different results .

Now the Kawasaki manual gives the specification as 0.05mm to 0.10mm . That has the inferred precision of +/- 0,005 mm.
Thus the spec now becomes 0.045mm to 0.105mm .

The actual amount of valve lash is not a critical measurement.
It is there to counter thermal expansion and while in theory it does change the valve timing in practice it makes very little difference on a mower engine.
Just so long as there is enough so the valve can close fully and not so much it negates the decompressor it is fine
I have run some B & S engines as tight as 0,002" because the cam was wearing down and that got a full season out of the motor so I could strip it down & replace the cam in the off season.

Double check you were setting the lash on the right stroke, remember there are 2 TDC's on a 4 stroke engine
Then double check that the lash has not changed since you set it .

One of the symptoms of a loose valve guide is the lash will be changing all of the time .
 
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