Valve clearance

[bertsmobile1]

An overtightened big end will be tight period, not go tight then loose unless the journal is very oval .
a bent rod can cause tight loose situation.
Is it the same plug in as plug out ?

 

[mmoustafa]

An overtightened big end will be tight period, not go tight then loose unless the journal is very oval .
a bent rod can cause tight loose situation.
Is it the same plug in as plug out ?

Yeah it’s the same with the spark plug in and out.
I am going to check to see if the flywheel key is still ok.

 

[bertsmobile1]

The valve spings get compressed and that will cause a resistance to rotation
MArk where the tight spot is on the flywheel and see if it is the same every revolution or every second revolution.
A con rod / piston problem will happen every revolution where as a valve cam type problem will be every second revolution.
If he seats have ben cut too deep & too much take off the valve stem or the valves are not seated properly the valve spring can bind
so watch the valves while rotating the engine as by hand as well .

 

[mmoustafa]

The valve spings get compressed and that will cause a resistance to rotation
MArk where the tight spot is on the flywheel and see if it is the same every revolution or every second revolution.
A con rod / piston problem will happen every revolution where as a valve cam type problem will be every second revolution.
If he seats have ben cut too deep & too much take off the valve stem or the valves are not seated properly the valve spring can bind
so watch the valves while rotating the engine as by hand as well .

I just finished draining the oil and have disassembled the fuel tank and muffler.
Will try what you’ve suggested @bertsmobile1 and let you know how it goes.
Thanks.
Regards.

 

[mmoustafa]

I just finished draining the oil and have disassembled the fuel tank and muffler.
Will try what you’ve suggested @bertsmobile1 and let you know how it goes.
Thanks.
Regards.

Hi all,
So I tested the mower last night and it was much smoother this time - at least it wasn’t getting stuck anymore.
I’m thinking it was getting stuck because I overfilled it with oil and this was creating additional resistance? Could this be the case?

The valves were moving smoothly but I also re-measured the clearances:
Intake = 0015” (spec is ~.008”)
Exhaust = .008”

I could see a faint spark when turning the flywheel by hand. I then tested the magneto with a multimeter and was getting 2.9 kohms (low end of the acceptable limit).ould this be causing ignition problems?

Lastly, how freely should the flywheel spin? Is it normal when turning the flywheel for there to be more resistance during certain strokes? Should the flywheel spin a little on its own when I give it a turn?

Much appreciated.
Regards.

 

[bertsmobile1]

You need energy to compress the springs on the valves so it should spin freely till the springs start to compress if there is no spark plug fitted .

 

[Scrubcadet10]

Hi all,
So I tested the mower last night and it was much smoother this time - at least it wasn’t getting stuck anymore.
I’m thinking it was getting stuck because I overfilled it with oil and this was creating additional resistance? Could this be the case?

The valves were moving smoothly but I also re-measured the clearances:
Intake = 0015” (spec is ~.008”)
Exhaust = .008”

I could see a faint spark when turning the flywheel by hand. I then tested the magneto with a multimeter and was getting 2.9 kohms (low end of the acceptable limit).ould this be causing ignition problems?

Lastly, how freely should the flywheel spin? Is it normal when turning the flywheel for there to be more resistance during certain strokes? Should the flywheel spin a little on its own when I give it a turn?

Much appreciated.
Regards.

so your intake valve has a clearance of 15 ten thousandths? unless my brain is failing me...
numbers don't mean much testing new ignition coils with the chip inside of them. usually either they spark or don't, or if they're bad, spark, but fail when hot.

 

[mmoustafa]

so your intake valve has a clearance of 15 ten thousandths? unless my brain is failing me...
numbers don't mean much testing new ignition coils with the chip inside of them. usually either they spark or don't, or if they're bad, spark, but fail when hot.

Yeah the clearance is way too low... so once I can get the engine started I plan to grind it down to spec and reinstall... I'm hoping the magneto is good...
Thanks again all for you help.. this forum is very beneficial

 

[Fish]

take out the plug and turn the engine over,
see if your plug is oily.
Yes, you need to do the exhaust valve correctly.

 

[mmoustafa]

take out the plug and turn the engine over,
see if your plug is oily.
Yes, you need to do the exhaust valve correctly.

Hi all,
So I managed to get the valves to spec and reassembled the engine. I left the carby off to test it. I did this by spraying some carb cleaner through the intake pipe.
After a few tries the engine completely seized ?
So I started by removing the spark plug and as soon as I removed it the cleaner squirted out. I continued until I stripped the whole engine and found a small metal lodged between the compression ring and the piston groove (see attached pics).
When rebuilding this engine I intentionally left out honing and replacement of rings because of cost and also because both seemed to be in good shape...

I’d like to hear your thoughts or ideas on how this could’ve happened and what to look out for moving forward?

Also, If I end up honing the cylinder, do I need to get a bigger piston?

Regards.