flyingace43
Forum Newbie
- Joined
- Sep 9, 2024
- Threads
- 0
- Messages
- 1
check the camshaft they have been known to bend.
Help!!!! Troy-Bilt
- Thread starter Bigdaddy's Craftsman
- Start date
Gord Baker
Well-Known Member
- Joined
- Aug 21, 2018
- Threads
- 1
- Messages
- 394
When an engine won't start, I try Starting Fluid. If it fires and dies, likely a Fuel Problem. If it does not fire, likely electrical - Coil and or Spark plug.
Confusion, Can you turn the engine over multiple times with the spark plug out while turning it by hand? If you can, install the spark plug and try cranking with the starter. If the starter turns but stops at full compression, or turns really hard, you have an exhaust valve adjustment problem. If it does not pull through, put a braker bar wrench on the pulley nut at the bottom of the crank shaft, or on the flywheel nut, and try to pull it through. If pulls hard but does pull through, it confirms the valve adjustment requirement. If it is stuck, you got a big problem. The exhaust valve adjustment is critical, like .005 or less, while intake can be .0008 or .0009. Check your engine guide for the exact clearances. The close tolerance allows the exhaust valve to open a little just before top dead canter and acts as a compression release to allow the engine to turn over more easily and is easier on the starter. These newer engines have higher compression. If the exhaust valve adjustment is too much the extra cam bump won't open the valve. There will be no compression release causing the engine turn over really hard. It is normally never the starter. Good luck
DinosaurMike
Member
- Joined
- Sep 23, 2011
- Threads
- 4
- Messages
- 32
Folks, the OP found his problem in post 15.
Why would this happen at the same time he changed drive belts?
Why would this happen at the same time he changed drive belts?
farmerdave1954
Member
- Joined
- May 6, 2023
- Threads
- 0
- Messages
- 17
Murphy's Law, 4th axiom. "If there is a possibility of several things going wrong, the one that will cause the most damage will be the one to go wrong. First corollary: If there is a worse time for something to go wrong, it will happen then."
Contrary to popular claims, coincidences DO happen. Unless the OP is lying about not doing something to the mower besides just removing the deck, this appears to be one.
Contrary to popular claims, coincidences DO happen. Unless the OP is lying about not doing something to the mower besides just removing the deck, this appears to be one.
I haven't read every post in this thread but I can tell you that it is highly, highly, highly and I mean again highly unlikely for a valve to drop on one of these engines unless somebody has been monkeying around in the valve cover and with stuff they shouldn't be messing with.
I saw in a couple of posts you commented about not being able to turn the engine over but then later said you had to plug out the whole time.
Then it sounded like you were giving some information about things you had saw or checked out that you would have had to have the valve cover off to see.
My best advice for people is always to get information from others (and hopefully it will be good information and these people know what they're talking about) BEFORE you start tearing into anything or taking anything apart and also before you start throwing parts at a problem which is what so many people do.
I have worked on thousands of these engines and I can't ever recall a time for a valve dropped on its own and cause any damage.
If one of these is running properly which it seems yours was before you pulled the deck off to do whatever to the spindles, that certainly shouldn't have made a valve keeper want to come out and drop a valve.
If it ever happens naturally on one of these engines it just loses the compression and dies because the valves are horizontal and the compression wants to blow them closed and soon as the keeper pops out and the retainer moves up you will get a valve that has no pressure to stay close so you'll typically lose compression or it will been to push rod from the rocker arms being out of alignment and stuff like that.
Regardless it will just lose power and run poorly or just stop running and it's highly unlikely to suck that valve or for it to end up far enough moved in the guide that the piston could ever hit It or break It off. Even if it moved a little bit the piston would lightly smack it and just make it close.
So it's hard for me to picture what actually happened with yours I just don't think it's common at all but some people are magnets for odd fluke things so anything is possible.
At this point, if you haven't fixed it already, you would be far better off just to go buy a good used running engine or even a mower which you can pick up for a hundred bucks or less that won't start and run or has a blown transmission and won't move on Craigslist or marketplace that has a similar engine to yours so you can transplant it.
Remember that over 80% of these lawn mowers out there that won't run and the people can't get to start only need the carburetor cleaned out.
It's simple enough to check this when you go that it's mechanically sound by taking a battery and jumper cables for a booster and a spray bottle of gas or a can of carb cleaner. (I don't even own a can of starting fluid and won't use it)
If you spray some car cleaner and the intake and crank the engine over with the key in the on position even if you have to jump it all the way straight to the starter, if it runs for 2 or 3 seconds on the fuel you give it then it's mechanically sound so there's your donor.
Just buying a piston and the bottom sump gasket (which if you buy Briggs I believe now only comes with the bolts for about $29) it's going to cost you as much as a replacement engine and a lot more time.
Even if you're doing your own work it is pretty much NEVER cost-effective to do any internal engine repair work when it involves the piston or rod.
It's barely worth doing if it's the camshaft for a busted ACR because buying a good or hopefully good Briggs camshaft will cost you $80 to $100 plus you need that gasket unless you can reuse yours but you can find some aftermarket gaskets now for about 10 bucks.
So you can get another engine that already runs for about 100 -$125 so it's close to being a little better.
But if it's a piston or a rod or run low on oil and smeared a bunch of aluminum onto the crankshaft, it's just not worth it and not cost-effective.
Now head repairs and valve train are not internal engine and most all of those can be fixed without even buying a new head which is the Briggs official repair but they're just selling you another lousy designed and lousy manufactured head to replace the one that just failed so I just fix the old ones and they're better than a new one in most cases.
Only if you have a junk pile of mowers with several of these engines laying around too scavenge good parts from is it cost effective to do but it's still not time effective.
Some people, of course, who tinker don't worry about this.
Will you do it as a professional shop speed is really of the utmost importance.
I have a feeling we don't have all the information or if we would have been there as a fly in the wall watching we would have spotted something that we would have been concerned about or said you shouldn't do.
Sure, sometimes weird things happen without any good reason but when you've worked on thousands of these engines and it's not a common or recurring situation, it just probably isn't going to happen without somebody doing something to cause it.
Engine hydro locked.... Remove spark plugs, crank engine. Crank until no more gas out of spark plug holes. Gas filled engine. Drain oil/gas, flush, refill with the oil.
Tiger Small Engine
Lawn Addict
- Joined
- Dec 7, 2022
- Threads
- 2
- Messages
- 1,084
This entire post is a great example of a few things. Diagnostic skills versus shooting in the dark. Listening and comprehension versus throwing parts at it. Experience versus “maybe this will fix it.”