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Compression Release
#1
J
jross
J
jross
I replaced the starter on the Cub Cadet 16.5 hp Briggs. With the spark plug out the engine cranks fast. With the plug in, it cranks until the compression stroke, and stalls. I adjusted the intake valve to .004 " and the exhaust to .007 " clearance at 1/4 " below TDC as per the Engine Manual. I turned the engine with a metal rod in the plug hole until the piston hit TDC, then moved it until I though it was 1/4 " below TDC. Even if I went past TDC 1/4 ", would it make that much difference?
#2
lizard
Sounds like your Starter motor is not working properly or your battery is no good
The Engine should turn over quickly even with the sparkplug in or out........nothing to do with valve clearance.
But saying that the tappets must be set according to your manuel, which might have to be done Cold or Hot .........otherwise the engine will not run correctly.:confused2:
lizard
I replaced the starter on the Cub Cadet 16.5 hp Briggs. With the spark plug out the engine cranks fast. With the plug in, it cranks until the compression stroke, and stalls. I adjusted the intake valve to .004 " and the exhaust to .007 " clearance at 1/4 " below TDC as per the Engine Manual. I turned the engine with a metal rod in the plug hole until the piston hit TDC, then moved it until I though it was 1/4 " below TDC. Even if I went past TDC 1/4 ", would it make that much difference?
Sounds like your Starter motor is not working properly or your battery is no good
The Engine should turn over quickly even with the sparkplug in or out........nothing to do with valve clearance.
But saying that the tappets must be set according to your manuel, which might have to be done Cold or Hot .........otherwise the engine will not run correctly.:confused2:
#3
K
KennyV
Did you replace the starter because of this problem??
Was it having this exact problem before you changed the starter?
If so , like lizard suggested it could be the battery...
Measure the voltage AT the starter while it is cranking the engine... THEN again measure the voltage ON the battery posts while cranking the engine with the starter... If these two voltage measurements are not the same you have a bad electrical connection between the battery and the starter...
If the voltages are near the same at both locations , how near 12 volts are the measurements. :smile:KennyV
K
KennyV
I replaced the starter on the Cub Cadet 16.5 hp Briggs.
Did you replace the starter because of this problem??
Was it having this exact problem before you changed the starter?
If so , like lizard suggested it could be the battery...
Measure the voltage AT the starter while it is cranking the engine... THEN again measure the voltage ON the battery posts while cranking the engine with the starter... If these two voltage measurements are not the same you have a bad electrical connection between the battery and the starter...
If the voltages are near the same at both locations , how near 12 volts are the measurements. :smile:KennyV
#4
J
jhwentworth
Yes, it will make a difference if the exhaust valve is set incorrectly. This engine has an internal compression release for starting (engine turning below 500 rpm) and the valves have to be set correctly for it to work. If you set the exhaust at .007", and were a little off, the clearance may be large enough to defeat the compression release. Try setting the exhaust clearance to .005".
I test the starter with a fully-charged battery and a set of jumper cables. Connect the positive terminal of the battery directly to the starter power lug, then connect the negative terminal to the tractor chassis or engine block. It might be best to first connect one negative lead to the tractor, then connect the other end to the battery negative terminal, because there will be some amount of arcing when the final connection is made. Testing this way eliminates the ignition switch, the solenoid, and all wiring connections as the source of the problem.
BTW: a fully-charged battery will read 12.7 volts, a reading of 12 volts indicates a 50% charged battery. At 11.5 volts you only have about 10% charge. Letting a battery get below 11 volts greatly decreases battery life.
J
jhwentworth
I replaced the starter on the Cub Cadet 16.5 hp Briggs. With the spark plug out the engine cranks fast. With the plug in, it cranks until the compression stroke, and stalls. I adjusted the intake valve to .004 " and the exhaust to .007 " clearance at 1/4 " below TDC as per the Engine Manual. I turned the engine with a metal rod in the plug hole until the piston hit TDC, then moved it until I though it was 1/4 " below TDC. Even if I went past TDC 1/4 ", would it make that much difference?
Yes, it will make a difference if the exhaust valve is set incorrectly. This engine has an internal compression release for starting (engine turning below 500 rpm) and the valves have to be set correctly for it to work. If you set the exhaust at .007", and were a little off, the clearance may be large enough to defeat the compression release. Try setting the exhaust clearance to .005".
I test the starter with a fully-charged battery and a set of jumper cables. Connect the positive terminal of the battery directly to the starter power lug, then connect the negative terminal to the tractor chassis or engine block. It might be best to first connect one negative lead to the tractor, then connect the other end to the battery negative terminal, because there will be some amount of arcing when the final connection is made. Testing this way eliminates the ignition switch, the solenoid, and all wiring connections as the source of the problem.
BTW: a fully-charged battery will read 12.7 volts, a reading of 12 volts indicates a 50% charged battery. At 11.5 volts you only have about 10% charge. Letting a battery get below 11 volts greatly decreases battery life.
#5
W
Walt 2002
W
Walt 2002
Might help if you posted the model numbers of the engine. MOST B&S engine relieve compression via the INTAKE Valve, not the exhaust. IF the engine is a V twin Vanguard, it will release via the Exhaust.
There is a whole litany of test procedures that you can utilize to narrow down the problem. For a partial list, address below, put in proper format and remind me.
Walt Conner
wconner5 at frontier dot com
There is a whole litany of test procedures that you can utilize to narrow down the problem. For a partial list, address below, put in proper format and remind me.
Walt Conner
wconner5 at frontier dot com
#6
J
jross
I used my tractor battery to spin the starter since the Cub Battery is marginal, installed a new solenoid and starter. The original starter is mostly ok I think, but the power connector lug separated where the brush lead is soldered to it, and the plastic insulator is broken n half. From the looks of it, someone was jumpering to the starter trying to turn the engine over which heated the solder enough to melt it. I have 13 volts at the starter and the battery.
J
jross
Did you replace the starter because of this problem??
Was it having this exact problem before you changed the starter?
If so , like lizard suggested it could be the battery...
Measure the voltage AT the starter while it is cranking the engine... THEN again measure the voltage ON the battery posts while cranking the engine with the starter... If these two voltage measurements are not the same you have a bad electrical connection between the battery and the starter...
If the voltages are near the same at both locations , how near 12 volts are the measurements. :smile:KennyV
I used my tractor battery to spin the starter since the Cub Battery is marginal, installed a new solenoid and starter. The original starter is mostly ok I think, but the power connector lug separated where the brush lead is soldered to it, and the plastic insulator is broken n half. From the looks of it, someone was jumpering to the starter trying to turn the engine over which heated the solder enough to melt it. I have 13 volts at the starter and the battery.
#7
J
jross
The engine booklet calls for .003-.005" on the intake valve and .005-.007" on the exhaust and the piston 1/4 " past dead center. I have to get a new set of feeler gauges. All I could find in the barn was one .004 and one .003 ( Haven't had a need for em in quite a while). I used the .003 for the intake and both the .003 and .004 for the exhaust, and .007 is at the top of the range.
J
jross
Yes, it will make a difference if the exhaust valve is set incorrectly. This engine has an internal compression release for starting (engine turning below 500 rpm) and the valves have to be set correctly for it to work. If you set the exhaust at .007", and were a little off, the clearance may be large enough to defeat the compression release. Try setting the exhaust clearance to .005".
I test the starter with a fully-charged battery and a set of jumper cables. Connect the positive terminal of the battery directly to the starter power lug, then connect the negative terminal to the tractor chassis or engine block. It might be best to first connect one negative lead to the tractor, then connect the other end to the battery negative terminal, because there will be some amount of arcing when the final connection is made. Testing this way eliminates the ignition switch, the solenoid, and all wiring connections as the source of the problem.
BTW: a fully-charged battery will read 12.7 volts, a reading of 12 volts indicates a 50% charged battery. At 11.5 volts you only have about 10% charge. Letting a battery get below 11 volts greatly decreases battery life.
The engine booklet calls for .003-.005" on the intake valve and .005-.007" on the exhaust and the piston 1/4 " past dead center. I have to get a new set of feeler gauges. All I could find in the barn was one .004 and one .003 ( Haven't had a need for em in quite a while). I used the .003 for the intake and both the .003 and .004 for the exhaust, and .007 is at the top of the range.
#8
J
jross
Engine model is 312777,type 015OE1, single cylinder. It says Cub Cadet, but it is a Briggs.
J
jross
Might help if you posted the model numbers of the engine. MOST B&S engine relieve compression via the INTAKE Valve, not the exhaust. IF the engine is a V twin Vanguard, it will release via the Exhaust.
There is a whole litany of test procedures that you can utilize to narrow down the problem. For a partial list, address below, put in proper format and remind me.
Walt Conner
wconner5 at frontier dot com
Engine model is 312777,type 015OE1, single cylinder. It says Cub Cadet, but it is a Briggs.
#9
K
KennyV
When it cranks to the point of stall... You are still measuring 13 volts (at the starter) ... while the starter is stalled and the battery is supplying all the current it can?
KennyV
K
KennyV
I used my tractor battery to spin the starter since the Cub Battery is marginal, installed a new solenoid and starter. The original starter is mostly ok I think, but the power connector lug separated where the brush lead is soldered to it, and the plastic insulator is broken n half. From the looks of it, someone was jumpering to the starter trying to turn the engine over which heated the solder enough to melt it. I have 13 volts at the starter and the battery.
I replaced the starter on the Cub Cadet 16.5 hp Briggs. With the spark plug out the engine cranks fast. With the plug in, it cranks until the compression stroke, and stalls. I adjusted the intake valve to .004 " and the exhaust to .007 " clearance at 1/4 " below TDC as per the Engine Manual. I turned the engine with a metal rod in the plug hole until the piston hit TDC, then moved it until I though it was 1/4 " below TDC. Even if I went past TDC 1/4 ", would it make that much difference?
When it cranks to the point of stall... You are still measuring 13 volts (at the starter) ... while the starter is stalled and the battery is supplying all the current it can?
KennyV
#10
W
Walt 2002
If you did the above correctly and it still does not want to crank, and engine is "Engine model is 312777," as you indicate, then you need to email me for a test included with my valve adjustment instructions. Address below, put in proper format and remind me what we are talking about.
Walt Conner
wconner5 at frontier dot com
W
Walt 2002
I replaced the starter on the Cub Cadet 16.5 hp Briggs. With the spark plug out the engine cranks fast. With the plug in, it cranks until the compression stroke, and stalls. I adjusted the intake valve to .004 " and the exhaust to .007 " clearance at 1/4 " below TDC as per the Engine Manual. I turned the engine with a metal rod in the plug hole until the piston hit TDC, then moved it until I though it was 1/4 " below TDC. Even if I went past TDC 1/4 ", would it make that much difference?
If you did the above correctly and it still does not want to crank, and engine is "Engine model is 312777," as you indicate, then you need to email me for a test included with my valve adjustment instructions. Address below, put in proper format and remind me what we are talking about.
Walt Conner
wconner5 at frontier dot com
#11
J
jross
J
jross
Update on the Cub Cadet 1600 resurrection. Replaced starter and battery, adjusted valves (Thanks everybody for all the help),and engine cranks, but will not fire. I think the ignition coil is bad since I removed the kill wire and it still will not fire. Once I did see a weak spark on the tester, but not since. Armature clearance is within specs and magnet is strong.
#12
J
jross
J
jross
I have the engine running. The mower is up in jack stands with the wheels off because I want to make sure everything mechanical is working before I invest in new wheels and tires. I shifted the tranny into forward/reverse and only the left axle turns. The right axle turns ever so slowly if at all. I didn't think to stop the left axle to see if the right axle would turn. The speed control seems to be working ok. Should both axles be turning? I can't remember when I last had a car up in the air and in gear, and if both wheels turned at the same speed. I don't think they did. If I have to replace the transaxle, further consideration about finishing this project is in the fore.
#13
K
KennyV
K
KennyV
There is a differential in there so you can slow or stop one wheel, (necessary for turning).
Some cars have limited slip or locking differentials... :smile:KennyV
Some cars have limited slip or locking differentials... :smile:KennyV
#14
J
jross
J
jross
Thanks to all here who have helped me get the Cub Cadet 1600 going. Drove it around the yard and it seems ok. The deck has a hole in the middle which has been welded over. I will grind the weld off and try to patch it with sheet metal if I can. The metal is from steel door cutouts which the previous owner has dumped in the back. The stuff wears well and rusts slowly, if at all, cuts and bends to contours easily. A new deck is $200, and I hit the budget limit getting it running, but maybe next spring? Thanks again to all, and to all, A Merry Christmas and a Happy New Year!
#15
I
ILENGINE
I
ILENGINE
valve adjustment are a ongoing thing with those 31 series engines. If not valve clearances it is worn cam lobes or the compression release return spring is broken or sticking on the cam shaft, I adjust about 30 of those a year, some twice the same year if they use them hard.