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I have a Husqvarna YTH 1846 with a Briggs 540 cc 18.5 hp mower that will not start. The last time it was used it started and ran fine. I got off the machine to open up a gate and when I tried to start it back up it would not start. When the key is turned the motor will turn over slightly and then stop. The battery is new, solenoid is good. The motor seems to turn over until it reaches the compression point and then stops. With the spark plug removed the motor will turn over normally. I tried adjusting the valves with no luck. Is it the starter or some other problem ? Thanks.

Since you have adjusted the valves then it is mostly a failure camshaft ACR and would require replacing the camshaft.

Are you running this down at a low idle? Say when getting off to open gates? Moving into the garage or field? Trying to save gas? Trying to slow the mower speed down by lowering revs?

That "new" battery will require load testing to confirm it is good.

leonlak said:

I tried adjusting the valves with no luck.

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Did you set them incorrectly? There are 2 top dead center strokes on a four stroke engine.

One valve all the way open or pushed into the head, adjust opposite valve. Rotate engine doing the same for the other valves. If one valve is open, other valves are safe to set.

StarTech said:

Since you have adjusted the valves then it is mostly a failure camshaft ACR and would require replacing the camshaft.

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Thanks. This is most likely the problem.

slomo said:

Are you running this down at a low idle? Say when getting off to open gates? Moving into the garage or field? Trying to save gas? Trying to slow the mower speed down by lowering revs?

That "new" battery will require load testing to confirm it is good.

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No, not lowering idle when getting off the mower. Will test the battery. Thanks for the reply.

slomo said:

Did you set them incorrectly? There are 2 top dead center strokes on a four stroke engine.

One valve all the way open or pushed into the head, adjust opposite valve. Rotate engine doing the same for the other valves. If one valve is open, other valves are safe to set.

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Thanks for your reply. I believe they were set correctly. It was done by my brother, who is a pretty good mechanic and I believe he checked them twice. I will run this by him and make sure they were done correctly.

leonlak said:

No, not lowering idle when getting off the mower. Will test the battery. Thanks for the reply.

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What I was getting at was if you lower the revs the battery might not charge proper. Keep her at 3600rpm. Some have a small charging coil of say 3 amps. One engine crank will take a while at topping off the battery at 3 amps.

Turn the engine backward against compression and see if it will start. That way you will have one revelotion with no compression and it will probably start. You can also take the valve cover off and turn the engine over and watch the lower rocker arm to see if it bumps off just before the piston reaches TDC on the compression stroke. If not the compression release is broken.

slomo said:

What I was getting at was if you lower the revs the battery might not charge proper. Keep her at 3600rpm. Some have a small charging coil of say 3 amps. One engine crank will take a while at topping off the battery at 3 amps.

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I do generally keep the revs high when using this machine, not sure if it has a charger though. Thanks.

hlw49 said:

Turn the engine backward against compression and see if it will start. That way you will have one revelotion with no compression and it will probably start. You can also take the valve cover off and turn the engine over and watch the lower rocker arm to see if it bumps off just before the piston reaches TDC on the compression stroke. If not the compression release is broken.

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Thanks for the reply. Will see if it does anything.

leonlak said:

I do generally keep the revs high when using this machine, not sure if it has a charger though. Thanks.

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I would add a Battery Tender brand. In winter, pull it from the mower and bring inside on the tender. Will make your battery last 2-3 times longer than leaving it outside.

slomo said:

I would add a Battery Tender brand. In winter, pull it from the mower and bring inside on the tender. Will make your battery last 2-3 times longer than leaving it outside.

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Thanks.

The problem looks like it is the camshaft. I've got a new one on order.

Thanks for all your help guys !