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Hi, new member here and looking for some input. I have about 10 year old Husqvarna YTH2041 42" 20Hp Briggs & Stratton that won't start all of a sudden.
I drove it into my shed after mowing the lawn 5 weeks ago and since we've been in a drought I haven't needed to mow but went to start it and nothing, maybe a 1/4 turn and dead. I thought it might be a battery, bought one and same thing. Returned thinking it might be dead, 2nd new battery same outcome. At that point I am thinking solenoid, starter or ignition, I ordered the parts the next week I go to turn it over and the new battery I bought the week prior was down to 3 volts. Hooked up jumper cables and the motor spun then gets caught up and can't get past the compression stroke. We pulled the cover and the keyway is in perfect condition, the vales aren't stuck so I am at a loss and trying to save $3,000 + buying a new machine especially since I have a great triple bagger that I modified from my old Craftsman to fit on the Husqvarna and everything I've looked at so far don't seem to be compatible with the bagger.

My one neighbor seems to think it's out of timing internally but as I stated the culprit you'd think it was, a twisted keyway, is not the issue that looks brand new. I've already had to change a head gasket on this motor about 3 years in and at the time was told the single cylinder is a bad design and the flaw is known to B&S but I don't know anything other than the damn thing cost me $300 to get fixed and now I can see a repair bill growing and growing since 2 mechanics by trade, were with me and don't know what to think at this point.

Any advice or feedback would be appreciated. I think I need to bite the bullet and buy the Zero Turn mower I always wanted but of course the wife thinks I should try to fix the 10 year old machine. It is in great condition otherwise so I wouldn't mind saving $3000+


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Thanks in advance,​

John

Before throwing more $$$$ at this unit you need to do a couple of things to find the problem.
1. Charge the battery.
2. Remove the spark plug.
3. Turn the engine over and see if it spins like it should.
4. If fuel comes flying out the plug hole your float needle and seat are no longer working properly and you will have to rebuild the carb with a new needle and seat. If this is the case you will probably find that fuel has migrated into the crankcase so after rebuilding the carb you are also going to have to change the oil.
5. If the engine spins over, but no fuel comes flying out, you should now remove the valve cover and check the valve timing and clearance.
Let us know what you find. When you report back be sure you include all engine numbers. At that point we will be able to tell you how to proceed.

Rivets said:

Before throwing more $$$$ at this unit you need to do a couple of things to find the problem.
1. Charge the battery.
2. Remove the spark plug.
3. Turn the engine over and see if it spins like it should.
4. If fuel comes flying out the plug hole your float needle and seat are no longer working properly and you will have to rebuild the carb with a new needle and seat. If this is the case you will probably find that fuel has migrated into the crankcase so after rebuilding the carb you are also going to have to change the oil.
5. If the engine spins over, but no fuel comes flying out, you should now remove the valve cover and check the valve timing and clearance.
Let us know what you find. When you report back be sure you include all engine numbers. At that point we will be able to tell you how to proceed.

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Thank you, back to work tomorrow so I'll takle this during the week. Fuel does come out when the plug is removed, I had to have jumper cables on the new battery to my car to get it to turn at all. Valve timing I believe was OK, I'll double check with my buddy because that's above my technical abilities but with the plug back in it would turn about halfway then get hung up on what I believe he said was the compression stroke. The plug was a little dirty I cleaned it with Emory cloth and it was getting decent spark just not at the right time to fire.

I can handle the carburetor part and figure out the valve timing with my buddy.

Which engine numbers are you referring to? The valve timing I'm assuming?

Thank you for the response, I really appreciate it.
JC

Fuel does come out when the plug is removed,

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that means the engine was hydro-locked. Fuel doesn't compress. Need to rebuild the carb and double check the needle and seat to be sure it seals. Also don't run it until you change the engine oil because it will have gasoline in it.

I would be checking the valve clearances first and while checking them check the ACR bump on the intake rocker (the one furtherest away from the flywheel). IF the rocker is not being bump (after the valve clearances have been adjusted) as the cylinder approaches TDC compression then the ACR on the camshaft is broken off and you would need a new camshaft. The 793880 camshaft is currently on back order until after Christmas. Don't try one of the after market ones either as several I have brought were bad right out of the box.

Or as said could be a hydro locked engine since fuel is coming out the plug hole but it is also likely the ACR/valve adjust problem. Both can cause the same symptoms.

StarTech said:

I would be checking the valve clearances first and while checking them check the ACR bump on the intake rocker (the one furtherest away from the flywheel). IF the rocker is not being bump (after the valve clearances have been adjusted) as the cylinder approaches TDC compression then the ACR on the camshaft is broken off and you would need a new camshaft. The 793880 camshaft is currently on back order until after Christmas. Don't try one of the after market ones either as several I have brought were bad right out of the box.

Or as said could be a hydro locked engine since fuel is coming out the plug hole but it is also likely the ACR/valve adjust problem. Both can cause the same symptoms.

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Thanks again. Now I'm determined to get it running. It's too clean to be junked already.

If the carburetor needle and seat are leaking fuel, clamp off the hose
going from the tank to the carb rather than let it hydro lock. I've had
success with that type problem by putting a fuel shutoff valve on it. When
finished mowing just turn the valve off and run it out of fuel. Also check
your oil to make sure it's not full of gasoline as well. May have to change it.