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Discussion Starter #1
craftsman 247.288852 LT2000
briggs straton 310000

Last season my aging battery would not turn over the engine... it would just slowing click and spin ... I had to jump from car to start and could use it and restart while hot. When cold, it would need a jump again. This season I replaced the battery with a new with same CCA and a little more CA battery. Now it just clicks and attempts to spin the motor but it will not start. Jumping has no effect.

Troubleshooting I have done (I need some help)
Thinking I have an electrical problem I disconnected the starter motor. At that large wire I get 12vdc when I turn the key.
With the starter connected, when I turn the key its only showing like 6Vdc. Same thing if I try to start it with the mower battery jumped from a car battery.
I also jumped from battery directly to the starter and it just clicks.

Hard to spin by hand with plug.... I removed the sparkplug and the motor spins freely. I checked the valves and they seemed ok but I readjusted them and that didnt do anything.

I am unclear how a bad starter would act. Would it just be dead or would it show low voltage or trouble starting like I describe? Am I just seeing voltage drop?
Can I rule out an electrical problem from what I describe?

Im fearing now that I have an engine issue. Any guesses?
 

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Hoosier Daddy
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The compression release mechanism on the cam could be bad. That would give you the stop on compression usually caused by the bottom valve being out of adjustment.

If you turn the engine by hand with the valve cover off, watch the bottom valve for a tiny bump movement before it fully engages. That little pre-movement is is the ACR working.

If you don't have that pre-movement (the bottom valve moves just like the top valve), you have an ACR problem, which requires engine removal, taking the sump off, and replacing the camshaft.

If you're lucky, it might be something else. :unsure:
 

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Discussion Starter #3
The last season or two it has been surging funny on startup, that was probably my warning. I hope its not what you describe as that is probably beyond my skill level and would be a costly repair.

Can i rule out the starter?
I have 12vdc up to the starter and i see voltage drop when i try to start... so Its certainly trying to spin the motor. When i remove the sparkplug and crank it, the starter is spinning the motor as you would expect without hesitation.

Also when i was cleaning electrical connections i accidently snipped off the diode on the alternator lead. I had to resolder it into the line. Im pretty sure i have it in the right direction.... grey banded cathode side closer to battery. If i screwed up that orientation, what would occur?
 

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Professional Homeowner
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Could be a connection issue. Inspect/remove/clean grounds and battery connections. Free test.

Could be the starter itself. Trying to use a starter with a bad battery can brick your starter over time; and it will show similar symptoms as a bad battery sometimes. A bad starter often draws more amps than a good one (another free test!), but it will also draw more amps if you have an ACR issue as mentioned above.
 

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Batte
The last season or two it has been surging funny on startup, that was probably my warning. I hope its not what you describe as that is probably beyond my skill level and would be a costly repair.

Can i rule out the starter?
I have 12vdc up to the starter and i see voltage drop when i try to start... so Its certainly trying to spin the motor. When i remove the sparkplug and crank it, the starter is spinning the motor as you would expect without hesitation.

Also when i was cleaning electrical connections i accidently snipped off the diode on the alternator lead. I had to resolder it into the line. Im pretty sure i have it in the right direction.... grey banded cathode side closer to battery. If i screwed up that orientation, what would occur?
Battery definitely wouldn't charge. I don't THINK the alternator would burn up as your battery shorts out, but I'm not 100% sure on that one. A diode is basically a one way valve for current.
 

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Discussion Starter #6
So if i had the diode wrong i wouldnt be seeing it trying to spin? As far as a bad joint, I used a jumper cable from battery post directly to starter post and the starter was just barely spinning it. Sometimes when it is trying to crank, i hear like a mini backfire..... I also noticed oil on the sparkplug, not sure how that plays into it.
 

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Discussion Starter #8
Can a bad starter be the issue even though it spins the engine freely with the spark plug removed?

Im unclear if starters fail open or can be intermittent/weak.
 

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I don't think your problem is the starter....at all......go back to response in Post#2 from Daddy John ...it is an easy and fast diagnostic step...and either eliminate that possibility as the problem ....or it is a reasonably easy fix
 

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Discussion Starter #10
Unless I am missing it, I do not see any difference in the way the two valves move. I was spinning it with the spark plug removed to make it easier.
 

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Discussion Starter #11
If the valves are not adjust properly, would I not see that "bump" as described?

I set both to .005 which is in range for both. I tightened the feeler gauge between the arm and valve until it wouldnt move back and forth then slightly let up enough that I could move the gauge back and forth with resistance and be able to pull it out and reinsert. I am not positive I am TDC either and did not use a screwdriver in sparkplug hole to do this. I had one valve fully open while the other was fully closed when I adjusted.

Should I try to be more precise or would close enough get me in the ballpark to at least have it turn over?
 

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With both valves adjusted close to .005", you should be able to feel the exhaust valve bump a tiny bit as you rotate the crankshaft. I would use the screen on the top of the flywheel, with a hand touching the rocker arm on the pushrod side. Going through two complete crankshaft revolutions would rotate the camshaft at least one turn, and would insure the CR has passed under the tappet at least one time.
If no 'bump', I expect the CR mechanism has decided to fall apart. That means removing the engine, and taking off the oil pan(sump), and likely replacing the camshaft.
tom
 

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on a 31000 the compression release is on the intake and the clearance spec is .003 to .005. Briggs says adjustment is tdc compression plus additional rotation to put piston back down cylinder by 1/4". Many agree that you can adlust 1 valve when the other is fully open. You might want to put intake at .003. You say you have checked connections. Does that include the chassis ground point? check this at section 17.35
web.ncf.ca/da229/smallengine/mtd-769-01415_electrical-2.pdf
 

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Discussion Starter #14 (Edited)
As far as electrical/grounds, I think its good. I cant get over that hump even if I connect directly to my car battery. Im starting to melt the jumper cables trying!

I reset the valves today again insuring I had top dead center (did not dial it back that 1/4") at .005 for both valves and still no dice. Does the valve clearance have anything to do with the compression/resistance it takes to spin the motor? I assume even if it wasnt to spec or exact, it would at least be able to spin the motor, just not fire up.

Should the resistance be the same, by hand, thru the entire rotation? The place its hanging up I have to use force to spin with two hands.

This engine is only 6 years old, does that change the likelyhood that its a broken internal? Im looking for any way not to have to take the engine apart. Ive watched a few videos about that little bump in the intake valve armature I should be seeing... I still dont see it on videos or on my engine... maybe its too subtle for my eyesight.
 

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Quote" I reset the valves today again insuring I had top dead center (did not dial it back that 1/4") at .005 for both valves and still no dice."
try doing it correctly. If at TDC you must go past to 1/4 down. You do that by continuing to rotate flywheel in clockwise direction. Do not turn it backward to move piston down. That's critical because of the compression release. Also the compression release fails when the clearance is too large (tappet doesn't reach valve for the bump to occur). That's why you should go to .003 and not .005.
Thinking that grounds are good is not as good as making sure they are good or testing that they are good.
 

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Discussion Starter #16
I reset intake to .003 and the exhaust to .005 at center plus approx 1/4" , no change. One last inquiry about electrical before i look at engine.

I notices a few things while checking my ground. I think there is a parasitic draw on the battery. I have new battery but after my numerous attempts to start it was appearing low So each time i was jumping the new battery from a car and putting it away for the night with a full charge. Im finding the battery is at 7vdc in the morning...

I also have continuity across the battery with it connected to the circuit. The starter, which is pulling 7amps when its trying to get over the hump, also has contiuity between +/- when i disconnect it frpm the circuit.

What if any of that is normal?
 

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Try disconnecting the cables (both of them) from the battery before putting it away for the night..and check in the morning .or just take it out and take battery in for a load test... a lot of new batteries are NG when sold .....I got one off the shelf in a place ...had it at the counter and saw the date tag that it was over 2 years old...when they sit that long without any use ....they can go bad.....but I don't think that is your main problem
 

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Ah the old starting issues strike again. May I suggest: 1. With battery fully charged, test at starter battery post ( I am assuming this is a solenoid shift starter) now leaving the tester hooked up attempt to start. If voltage drops below about 8 volts check your battery connections and if needed clean them also be sure to check the battery ground cable where it attaches to the frame or engine be sure it is good. Now if you still have 8 volts or less at the starter I would believe you have a starter issue. If you solenoid is not mounted on the starter the same applies except you can better test before and after the solenoid. 12 volt on the battery post side try to start voltage drops clean connections or replace wires or battery-- 12 volts battery post side try to start no or low voltage on starter side-- Bad solenoid or starter. 2.If you were trying to work with a dead or low battery every time you tried to start the solenoid was slow to react and every time it attempted to make contact it burned the posts and disc the makes contact, eventually it carbons up and cannot make contact sooo click -click-click some times it may make contact if attempted enough and work. 3. As for the compression release if the engine starts to turn and just won't go over compression it may be the issue. To check remove valve cover be sure valves are set correctly usually set best just past tdc on the compression stroke. When completed turn the engine very slowly and observe the rocker arms on the compression stroke you should notice the lowest rocker just move slightly as the piston moves up toward TDC. Yes those Briggs single cylinders seem to fail the compression too often. If bad need to remove base and replace the cam shaft. 4. to check for a battery draw remove the ground cable make the room dark as possible touch the cable to the post and observe for a spark or if you have a multimeter set on amps remove cable and put the meter "in the circuit" read the draw if any. A bad battery would show up as draining if left unhooked by doing a voltage check after a period of time
 

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Discussion Starter #20
Thank you all for your help. Maybe I had some progress this morning.

I was able to get it to start by blocking the air intake. What does this mean?

Im assuming with that I can rule out electrical, starter and valve adjustments.... and hopefully engine removal and crankshaft replacement!
 
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