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Have a push lawn mover with Honda GCV160 engine. The mower has proper amount of oil in it which is two seasons old and not dark so seams ok. I left the mower over winter with premium gas (half tank) in it. Darn, I should have properly winterized it and emptied the tank.
Now I can't pull the string. Nothing is stuck with the blade. I can rotate the blade with hand but it's not rotating easily and also it gets harder to rotate after a little bit of rotating, it releases, and then the same thing happens. I removed the spark plug and then I could pull the rope but rotating the blade is still the same and a little hard. The spark plug seems normal with no sign of oil or any other dirt on it. I read somewhere to add a little bit of penetrating oil and I added a bit of WD40 into the spark plug hole. Let it sit overnight. I tried again in the morning and it's the same thing. Any idea what could be wrong and how I can fix it?

Remove the spark plug, Squeeze the handle that releases the blade brake and pull the starter rope; the engine should rotate easily. If it doesn't, either the blade brake isn't releasing or you have internal engine problems. I doubt that you have internal engine problems if it was running when you put it away last year.

Thanks for your reply. You are absolutely correct. When I removed the spark plug, I could pull the starter rope easily. But when I reinstalled the spark plug, it was again the same thing and could not pull the starter rope again. What could be the problem from your point of view?

Hydro locked. Remove the spark plug and tilt the mower to see if any liquid will run out.

Also, your compression release may not be working. That IS an internal problem.

I tilted the mower but no liquid came out. the park plug was completely dry when I removed it. I added some WD-40 though trying to lube the piston. Could the problem be from a faulty spark plug?

probably the reason it gets hard to turn by hand, then easy, then hard is you're feeling the compression stroke in which both valves are closed, and the piston is compressing the air and fuel for combustion.

It sounds to me like the blade brake isn't releasing, when you pull the brake handle down on the handle where you push mower do you feel resistance to you pulling it, if you don't feel any resistance something is broken or pulled loose from brake.

Scrubcadet10 said:

probably the reason it gets hard to turn by hand, then easy, then hard is you're feeling the compression stroke in which both valves are closed, and the piston is compressing the air and fuel for combustion.

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I lubed inside the cylinder with WD-40 and now I could rotate the blade by hand easier without so much of that feeling of getting easy then hard then easy. But what you mentioned makes sense.

gainestruk said:

It sounds to me like the blade brake isn't releasing, when you pull the brake handle down on the handle where you push mower do you feel resistance to you pulling it, if you don't feel any resistance something is broken or pulled loose from brake.

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Thanks! I checked the blade break and it feels like normal. There is some resistance like always nothing different.

I checked it again now and the pull string was the same. To better describe it, I should say when I pull the string I could pull a little bit then it stuck, then with a little more force I could pull a little more and then it stuck again. Could the problem be from "compression release" that @cpurvis mentioned? If yes, is there a way to repair it?

Sounds like failed compression release. 1st you have to definitively diagnose. 1st step is remove blower housing and see if flywheel brake is staying off the flywheel when bail handle is pulled closed.

dougand3 said:

Sounds like failed compression release. 1st you have to definitively diagnose. 1st step is remove blower housing and see if flywheel brake is staying off the flywheel when bail handle is pulled closed.

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Thanks! Yes. I checked and the flywheel brake is staying off the flywheel when bail handle is pulled closed. What's the next step?

Pull the OHV cover and see if valves work when you pull rope. You'll watch rocker arms - when they go down - valve is opening. Intake valve opens, then closes; Exhaust valve opens, then closes. Check the valve clearances - between rocker arm and valve stem - many youtube videos.

dougand3 said:

Pull the OHV cover and see if valves work when you pull rope. You'll watch rocker arms - when they go down - valve is opening. Intake valve opens, then closes; Exhaust valve opens, then closes. Check the valve clearances - between rocker arm and valve stem - many youtube videos.

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Yes, I forgot the valve clearance issue. Having the correct valve clearance is necessary for some compression releases to work.

dougand3 said:

Pull the OHV cover and see if valves work when you pull rope. You'll watch rocker arms - when they go down - valve is opening. Intake valve opens, then closes; Exhaust valve opens, then closes. Check the valve clearances - between rocker arm and valve stem - many youtube videos.

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I finally was able to do adjust the valve clearances last night and let the gasket silicon cure for 24 hrs (for securing valve cover) and tried the mower tonight, but it didn't work unfortunately. There was almost no clearance and I adjusted them hoping that was the issue. What else could it be?

cpurvis said:

Yes, I forgot the valve clearance issue. Having the correct valve clearance is necessary for some compression releases to work.

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It didn't work. I adjusted the valve clearances. what else could it be?

It's when the valves have too much clearance that the compression release doesn't work. Are you sure you set the valves correctly? This time, don't put the valve cover back on before you try it to see if the problem is fixed.

This assumes your compression release is a small bump on the exhaust lobe, and that may not be a good assumption at all. Hopefully one of the pros on here who is familiar with your engine (I'm not) will help out.

cpurvis said:

It's when the valves have too much clearance that the compression release doesn't work. Are you sure you set the valves correctly? This time, don't put the valve cover back on before you try it to see if the problem is fixed.

This assumes your compression release is a small bump on the exhaust lobe, and that may not be a good assumption at all. Hopefully one of the pros on here who is familiar with your engine (I'm not) will help out.

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Was going to say the same thing. Might be 180 degrees out.

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