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Lawn Tractor Mechanic Needed...

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banjoman09

Well-known Member
Is this topic suited for this forum...a need a good Craftsman 21.0 lawn tractor mechanic...if not...Ill repost on another forum. Thanks.
 
Yes...first off- thank you Jim. I did post on there but no one seems to answer. I have a 2012 Craftsman mower with a 540cc engine.; new battery(checked it also), when you try to start it hits the compression stroke and quits...then goes ahead and does it again. I pulled the plug and gas in cylinder so cranked it til gas was gone; pulled valve cover and checked valves- .004 to .005 so they were already correct. Put plug back in and does same thing...any thoughts? Thanks for saying "post":)
 
Banjoman09, I had one that the electric solenoid valve on the bottom of the carb was not shutting off the gas and the cylinder would fill with gas. Once I got the gas out of the cylinder it would usually start. I truly believe the longevity of the mower was compromised because of this, even though I put a manual shutoff once I figured out what was happening. Hope this may be helpful gobble
 
Sounds like the carburetor float is letting too much gas to the engine. I would take the bowl off and see if the float is stuck or needle is bad. Ron MN
 
Yes..the other problem is when it is shut off the gas will drain into the engine while sitting; float or solenoid? But, the other problem- I did crank over without the plug and dried out cylinder and it still does it. Thanks.
 
There could be a compression relief device on the camshaft. It holds open intake valve through part of the compression stroke to make it easy to turn. I have had one that needed 4 gauge cables to the starter motor and ground to let it start well. Jim
 
Banjo, certain small engines require the valve clearances to be set an certain amount of piston travel AFTER TDC for the compression release to function properly.

Don't know if that's the case with your engine, but if it IS and you are checking the valve clearance at TDC instead of where the mfg. states it should be set the compression release function won't work and the engine will act as you describe.

Are you checking the valve clearances as the engine-specific shop manual dictates?
 
If that has the Nikie carburator on it that is your gas problem. The fuel inlet seat where the float valve is is aluminum and they corrode to where they wont shut off and filling the cylinder with fuel and eventually the crank case. Then they hydraulic and wont turn over. But as others have said the valves needing to be set can cause almost identical symptoms. But you said you had gass in the cylinder.
 
I have the same problem from time to time. Under the carburetor bowl is a little electric shutoff that gets dirt or just sticks open. When it happens the gas tank empties into the engine. I took it apart several times and never seem to see anything but it works fine for a while. I have been using it to do chores when I can this winter with it happening only once. I bought a new carburetor and will put it on as soon as it warms up. I make sure the gas is all out of the tank and engine and only put a small amount of gas in the tank when restarting after taking the carburetor apart. I do make sure the spark plug is clear with compressed air. Some times I change spark plugs.
 
Yes....quite abit of gas in cylinder when I pulled plug- cleaned it out and still started hard. Im not sure where to find parts for this mower; and what the valve setting specs are? Anyone know this? I may have two separate problems. Thanks.
 
I bought one with the symptom of what you describe for $50. It was 1 year old. it was so full of gas in the cylinder and crank case it wouldn't turn over. I drained 2 gallons of oilgas from the crank case and cleared the cylinder. Installed a fuel shut off on it and used it after every time i run it.
 
I got mine off Ebay. I just put the engine model number in the Ebay search after engine make and the word carburetor. Several choices came up. I chose the one with the most positive feed backs.

I wouldn't screw with valve setting or any adjustments until after I found it was not the solenoid. If it turns easy with the plug out and starts to turn hard after the plug is back in you still have gas in the system getting on top of the piston. I have the carburetor off mine many times thinking it can't be that big of a deal. I have been rebuilding my own carburetors for 50 years and it is to simple to stump an ole duffer like me. I put a new inline filter in the last time after cleaning the gas tank and fuel line. I started up easy this morning yet. Changing the carburetor is only two bolts after the air filter is removed but my 80 year old crippled fingers don't work all that well in the cold.
 
Ok...I did look on Ebay last night and didn't find much for a 21.0 - 540cc in new...but will look again today. It will need this to stop the gas leaking; Utube video shows set valves at TDC; they seem to be right. I will check all cables also to be sure- but they look good. Thanks for the help.:)
 
ok....still not sure why it hits hard on compression after I cleared gas out of cylinder and put plug back in...?
 

21hp.....has to be a two cylinder, right?
Have you confirmed valves are opening an closing like they should?
Via valve covers off?
Is gas filling both cylinders or just one? Or are you just getting a handful of gas out of cylinders when you clear them?

Also, before you start it put your hand on the carb solenoid, turn key to energize but not all the way to cranking.
You should be able to feel the solenoid clunk open inside of it.
I will say I am not 100% on this but I am thinking it is a closed when off solenoid and opens upon ignition on.
You will have to be seated to activate seat switch when doing this test.
 

I would install a manual shut-off valve in the fuel line and forget it (not the shut-off valve..!!

At the first thought that fuel is flooding the engine during shut-off, I would have it on there..just put it where you can get to it easily and will not
forget it..!!
 
The only thing the solenoid does is plugs the main-jet to stop it from running when hot. There can be problems with the solenoid but usually wont run at all. It wont make the carb run over.
 
This mower is my neighbors.... there is one in the line; thats fine....it is still locking on crank ...thats my main problem.
Thanks.
 
Jim...on the electrical...don't laugh to hard but the cables are standard- I mean they came new on the tractor; they measure 1/4" wide....not sure the gauge? The battery is Walmart...230 amp..one yr old battery...seems to to load test ok. Thanks.
 
Ok...on the fuel problem..I will replace carb with the solenoid. Got that covered...in the mean time ...this engine should turn over fine with the gas "shut-off"...no gas in cylinders...but it does not.
 
Have you checked the oil level? Mine does that when the electric fuel solenoid doesn't shut off and lets gas drain into the oil pan. Had to replace the solenoid.
 
Had that happen on many over head valve B/S engines and the setting of the valve has to be spot on or the compression release will not work so the starter does not have the power to spin it over all the way. I worked a few times as a lawn mower repair man
 
Videos show the 21.0 to set valves on TDC...is this correct or where do we find out? I think it is in the mechanical part...valve setting or something else....how does the "release" work and can it be bad in the engine? Thanks.
 
If you see a carburator on Ebay for this engine please send me the item number. Briggs and Straton- 540cc...21.0... thanks.
 
I always set the valves this way. You turn the engine till one valve opens and that is when you set the closed valve. That way your 1000% sure the valve your setting is in fact closed. The compression release as I understand it open a valve just a little bit as it hits TDC so the engine can spin over fast. Works sort of like the petcocks on the older JD 2 cylinder tractor but instead of the person opening and closing them the engine if built to do it. I have 2 or 3 of those engines laying around on the place in riding lawn mowers I have. Those engines also like to blow the head gasket in such a way as to dump oil into the cylinders and then you have a smoke bomb of an engine. I have one that blew that gasket and you could start it up but if you stepped away from it you could not see if due to all the smoke
 
I think you can google up a explanation of just how that compression release works on those engines. Adjusting the valves is very exacting on those overhead valve engines as there is no separate device kicking that valve slightly off it's seat for starting. All is in the camshaft grind. I think (not 100 per cent sure) you have to adjust slightly after tdc. Turning engine over and checking the setting at slightly different crankshaft positions, all close to tdc, should show different readings. We went through the starting problem for a long time on Kohler engines before they put in their version of centrifical operated compression release mechanism.
 
ok...will try to find the info...maybe I should check the flywheel key also- but he said when they do get it to start it runs fine. Thanks.
 
Maybe mine is different. The solenoid is hooked to the switch and when turned off closes. Nothing hooked to shut off when hot. On mine when held on with a jumper gas gets in the engine. The last two times I only removed the solenoid and metal bowl to blow it out and that stopped gas from getting in the engine. My Craftsman has a Kohler engine.
Is This It
 
No Sir... I just took off the top cover...it is a single cylinder...yep.....21.0 540cc single. Briggs and Stratton Platinum engine....thank you:)
 
Briggs 21.0 Platinum carb....2012
a259677.jpg
 
I have a rider that had the same basic issues you are talking about. What I found is my fuel pump runs off of a pulse line in the motor. The diaphram had ruptured and when stopped it would load the crankcase through the pulse line. In my situation a fuel shut off would not have worked. The new fuel pump fixed that problem. The starting problem on mine was the valve settings. There is a number on the side of the motor that you need to look up and see what specs to use. Mine the valves are set at I believe about 4 degrees after tdc. Check the specs and set them just like it says and it will make a world of difference.

Steven
 
I took the valve cover back off and all looks good in there; I did notice when the intake opens -Im not seeing the extra "Bump" they talk about before the intake opens...is there something wrong in the motor? Thanks. My exhaust is about .004 and intake is .005.
 
Ya, it takes a lot of googling to get what one is looking for sometimes. I did it a couple years ago on one of those engines. It was a 17 horse overhead valve that started burning oil because of a blown head gasket. Valve pushrod chamber right next to cylinder head allowed a whole lot of oil to get drawn into cylinder. I had no idea when I started to work on it that it was designed that way so had pulled engine out as I expected a major piston job. So, that is how I got into the valve adjusting procedure. I don't remember for sure where I got good information but do remember it took a while and eventually pulled it up on the computer. I think it ends up piston is supposed to be like a quarter inch down after top dead center but don't quote me on that. Keep looking.
 
If I understand correctly, the engine locks up when turning it over to start. If that is the case you have a bad compression release on the cam shaft. New cam runs about $85.
 
Thats the most logical answer I have had so far...makes sense to me..so how do they go bad? Mower is 6 yrs old...I have to take off engine and disassemble....correct? I have a few answers at the bottom of this post you might read...thanks for your help. Where do I buy a new carb?
 
Hello banjoman,and

Exhaust valve setting Is .005 to .007. Set it at .006. Assuming the e!electrical part is all working? If it does not solve the problem then your compression release in not working. While setting the exhaust valve make sure the intake is fully open. You should be able to see the intake valve bump from the compression release while turning the engine,and the valve comes up-colses on the compression stroke,

Guido.
 
I really don't know the real reason they break or go bad. You remove the engine, remove the bottom sump and you can then remove the cam. The new cam comes with new lifters.

This video will show you the cam replacement. Just ignore the skit this guy puts on.
https://www.youtube.com/watch?v=dWHPHGZAvj4
 
Oh my..... he is nuts. lol..I have seen him before but have a hard time looking at him... there all crazy! Thanks it is a good video...may have to get parts coming...thats the problem! Thanks again:) Banjoman09
 
Hmmm....interesting....tell me why this solenoid is $7 and Sears is $60 ? He also lists a carb that looks right for $20 ? Whats the deal ? Thanks for your help.
 
Check your starter.
You said the mower is six years old. That's a lot of cranking for a starter.
If the bushings are bad, especially at the commutator end, the starter will drag.
 
There has to be a local lawn repair shop in your area give them a call and with the type and serial number they should be able to give you the correct valve setting. If my friend still worked at the local shop I would give him a call and find out for you but he had a heart attack and stroke a year or so ago which has disabled him so he can no longer work. Sad thing is, is he is only in his 50s
 
The one video I watched, the dude with the weird teeth, says they set at .004 ? So im kinda confused...maybe I will do .005. Thanks! I am ordering a camshaft today .
 
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