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I knew buying a mower off Craigslist for less than $500 wasn't going to get me much of a mower..... but, it was sold to me as a god mower in full working condition. It got delivered, started up fine, and I cut for a few minutes. Then I realized there was a rake on the lawn so I turned off the mower to move the rake. That's when the fun started.....

I tried to start the engine again and it just turned over and over without firing up. Then after 4-5 attempts to start it the battery had died. I charged it back up, charger said 100%, and tried again. This time it seemed to struggle to even turn over, and after two attempts I can now only hear a faint buzzing sound and the engine doesn't turn at all.

The person who sold it to me said the battery was brand new, and as I said it fired up OK the first couple of times but everything's gone downhill since

Any advice would be appreciated

(17.5hp Briggs engine)

Welcome
Sounds like the classic decompression problem.
Check the starting system by cranking without a plug in the hole.
If the motor spins freely then you need to adjust the valve lash and for instruction on that we need the model number & code from the engine.
And the model number of the mower itself won't hurt either

Firstly thanks for your reply! The mower is model 917 272673 and the engine is a Briggs 17hp 42A707

Any help is very gratefully received

I will make a bold assumption in that it did not come with a manual.
So go to the sears website and download a free copy of the instructions and if available the parts book.

There are a few things that can go wrong to stop it from starting & as it happened when you got off the prime suspect is the safety switch under the seat.
If the plug has fallen off the switch, the mower will not spark.
If the brake is not fully applied the mower will not spark.
I either switch is faulty it will not spark
If the shift is not in neutral it may not spark or might not crank or both ( wiring varies on this one )

Before you try & crank the engien again pull the spark plug because it also could have a bad needle in the carb and the cylinder may be full of liquid petrol which will not compress and can do a lot of damage.

If the mower backfired when you stopped it you could have sheared off the the timing key in the flywheel.

Correct, no manual.

When I got off I tried to re-start and it was turning over but not firing. Then after a few more attempts it felt like the battery died. I then charged the battery fully but after that it sounded like it was really struggling to turnover, nowhere near firing, and then after a couple of attempts like that it turned to a click/buzzing noise when I turned the ignition.

So it sounds like something deteriorated fairly quickly. Could it be compression? Or a blocked air filter? I've taken out the air filter and it's definitely old and in need of replacing.

Thanks

First thing we are going to need to rule out is the battery connections. Make sure they are clean and tight. Next step would be to have the battery load tested at a local auto parts store. Next possibly things would be the starter has overheated and is now failing. If the battery fixes the cranking issue. you will need to remove the spark plugs and reattach one to a wire and while holding it against a good ground on the engine. crank the engine and see if you have spark.

I suspect the battery has shorted a cell internally and has failed. I also suspect that the ignition module has either failed, or there is something wrong with the key switch and sent 12 v to the module and killed it.

If bat has screw top cells and you cannot/don't load test look at the condition of the electrolyte. The buzzing/clicking is classic low bat as the guys have said.

CRAFTSMAN LAWN TRACTOR Parts | Model 917272673 | Sears PartsDirect

Manual Craftsman Lawn tractor 917272673 | SearsPartsDirect download manual, wiring diagram page 31, check 20 amp fuse, raise seat & check out safety switch.

OK thanks. I've taken another look tonight before I look at the battery and other suggested things tomorrow, and a few things to add:

- Spark plugs were dark, not overly wet, but they were very dark
- Oil level was high, well past the max level
- PHOTO ADDED to show a broken wire that I've just seen for the first time. No idea if it was always like that or if I've accidentally caught the wire with my foot.

Battery was fully charged again so I tried the ignition and the flywheel turns, stops, turns, stops.... as if it's not getting enough power but I suspect it isn't a battery issue.

Thanks again!

ILENGINE said:

First thing we are going to need to rule out is the battery connections. Make sure they are clean and tight. Next step would be to have the battery load tested at a local auto parts store.

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Yep, I would start with these first.

OK I've got the mower running again thanks to your help - but, it will now mow for 2-3 minutes before cutting out and won't restart until after 20-30 mins.

To get it back up and running I cleaned the battery connectors and made sure they were tight, replaced the air filter, cleaned the fuel cap etc and now it seems to start relatively well.

It mows well up until the point it cuts out, and it's happened today climbing a small hill. I had to increase the throttle to get up the hill in 4th / 5th gear, and then it started to struggle. I'm not sure if the hill is connected or it was coincidence, but either way yesterday and today I had it running for 2-3 minutes of cutting before it gave up.

Any ideas what to check next?

Thanks!

craftsmannc said:

OK I've got the mower running again thanks to your help - but, it will now mow for 2-3 minutes before cutting out and won't restart until after 20-30 mins.

To get it back up and running I cleaned the battery connectors and made sure they were tight, replaced the air filter, cleaned the fuel cap etc and now it seems to start relatively well.

It mows well up until the point it cuts out, and it's happened today climbing a small hill. I had to increase the throttle to get up the hill in 4th / 5th gear, and then it started to struggle. I'm not sure if the hill is connected or it was coincidence, but either way yesterday and today I had it running for 2-3 minutes of cutting before it gave up.

Any ideas what to check next?

Thanks!

Click to expand...

Try loosening the fuel can a 1/2 turn or so . It might not be venting and stopping the fuel supply.
When running it should behave the same way as the mower dieing out after you have turned off the fuel tap if you have a venting problem.

The other dying when hot biggie is a failing ignition module test that by checking for regular spark the instant the engine dies.

When faced with this type of problem I pop in an inline spark tester and watch it as the machine heat up. Usually I can pick it starting to flicker if there is an ignition problem.
If this is the case try a second time with the magneto cut out wire disconnected , same thing happens the a new module is the expensive answer.

for smaller engines like chainsaws I use the inductive tacho but that is an expensive piece of kit that is easily damaged so it stays in the shop.

I've tried the gas cap as I read that on here before and no luck - didn't change anything unfortunately.

I've also read a few different posts about the ignition module being to blame for this problem, so I'm going to order one and use it as a last resort once I've replaced the gas lines, gas filter, and refreshed the carb.

Is this the right part to be ordering?

Amazon.com : Stens part #440-441, Solid State Module : Industrial & Scientific

Thanks!

Looks like the correct one.

before you shell out for a new module, try buying the in line spark tester which is about $ 5.00 and watch what is happening when it dies.
They are a really handy tool the can be used on anything with a spark plug.

OK will do - I've just ordered one on Amazon for $8 so I'll test later this week and then let you know how it's looking. Just to confirm, you're saying use the mower, wait for it to cut out and then use the in line tester tool. Do I then just try starting it again and test both spark plugs?

Thanks

If I suspect that I have a module going bad I will connect the inline tester before starting the mower, and then run it till it quits, and watch the spark as it is dying. No spark replace module,. Some engines also have a fuel solenoid on the carb, and will act similar. If you have a solenoid, and the spark doesn't disappear, then cycle the key on and off, and listen for the click of the solenoid. No click replace fuel solenoid.

I think the Briggs 42A707 does have a solenoid, but as far as I can remember I haven't ever heard a click when turning the ignition since I got it a week or so ago. I've done a lot of playing around with it and probably started it 20 times, but to my knowledge no click. Can you show me what the solenoid should look like so I can double check if there is one on my engine?

Again really appreciate all of your help.... I'm slowly learning!

Perhaps observe when the misses/spark failure occur with regard to engine temp. When the internals are fried the module typically works cold and fails at operating temp.

craftsmannc said:

I think the Briggs 42A707 does have a solenoid, but as far as I can remember I haven't ever heard a click when turning the ignition since I got it a week or so ago. I've done a lot of playing around with it and probably started it 20 times, but to my knowledge no click. Can you show me what the solenoid should look like so I can double check if there is one on my engine?

Again really appreciate all of your help.... I'm slowly learning!

Click to expand...

if looking at the carb, it should be on the right side, with one or two wires coming out of it.

OK thanks. I definitely think it's a temp issue - I can let the engine idle and it will sit there for a good while without struggling. As soon as I start to mow and take on the hill in my yard it cuts out within 2-3 minutes. It appear to me that when the engine has to start working something quits, so a temp related issue would make sense.

An in-line tester would be ideal but you could just use a known good spark plug and check for spark when it's happening.

craftsmannc said:

OK will do - I've just ordered one on Amazon for $8 so I'll test later this week and then let you know how it's looking. Just to confirm, you're saying use the mower, wait for it to cut out and then use the in line tester tool. Do I then just try starting it again and test both spark plugs?

Thanks

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Bugger they have gone up.
As Ilengine posted, pop it on and watch what it does as the engine is dying.
Now it will not tell you if the plug is firing properly it will just show that the module is sending a power pulse to the plug.
It could be shorting out inside the plug all you will know is that the module is working and that is all you are testing.
One thing at a time once you know that both the modules are working then you have eliminated them and all of the ignition cut out wiring.
So you have eliminated 1/3 of the possibleites.

I am a working mechanic and for me time is money.
Being independant I am lucky to see two of the same brand of equipment in any week let alone two of the same units with the same problem.
So the two tools that get used most are the inline tester and the colortune .
Just one little thing I also did was to make up a plug lead extension so I can see the tester when sitting in the seat using the mower

I fixed it! Thanks again everyone - turns out a thorough clean of the carb and the fuel filter solved the problem. It must have been fine at idle but then when the engine needed to work it couldn't draw enough fuel through.

Now on to my next minor issue - it drives fine in all gear, but reverse is very slow and 1-4 are very slow. 5th and 6th gear is fly's! 5th gear is too fast and 4th gear seems like less than walking pace, as in someone with a push mower would beat me. My lawn in an odd shape and I don't have long stretches, so I'm not looking to mow in 5th but 4th is making it a longer job than it should be! Would this be a drive belt issue?

craftsmannc said:

I fixed it! Thanks again everyone - turns out a thorough clean of the carb and the fuel filter solved the problem. It must have been fine at idle but then when the engine needed to work it couldn't draw enough fuel through.

Now on to my next minor issue - it drives fine in all gear, but reverse is very slow and 1-4 are very slow. 5th and 6th gear is fly's! 5th gear is too fast and 4th gear seems like less than walking pace, as in someone with a push mower would beat me. My lawn in an odd shape and I don't have long stretches, so I'm not looking to mow in 5th but 4th is making it a longer job than it should be! Would this be a drive belt issue?

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I'd say that if you don't smell rubber burning then that's just your gear ratio in the trans. If you want to take the easy way out, you can invest in some bigger tires. That'll increase your speed depending on how big the new tires are.. You can probably find some on craigslist pretty cheap. But you might have to buy a junk mower to get them. But that's ok, (if you have room for it).. You can always used the extra mower as a hobby rebuild. Or take off the tires you need and sell or junk the rest.