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Mower Wont Start
#1
B
BLM69SS
B
BLM69SS
Can't get my 2003 Toro Super Recycler with a 6.5 Briggs and Stratton to start. Last time I used it which was a couple weeks ago it ran fine and I had a normal shutdown. Went to use the mower again and it just won't start. So far I have put a brand new plug in it/I have installed a different ignition coil even though the other was producing a spark with the plug laid against the head/ tore it down and inspected the flywheel key which was fine/I removed and inspected the muffler/removed and cleaned the air filter. I have pulled the start rope approx. 300 times and have never gotten the engine to even sputter or try to start. I have bypassed the carburetor and sprayed/injected fresh gasoline and ether into the carburetor intake and then directly into the combustion chamber and got nothing. I have held my finger over the spark plug hole and can feel the piston pushing and sucking so that tells me the valves are working and it is making combustion. What am I missing? What else could it be?
#2
M
mechanic mark
M
mechanic mark
Post your B&S numbers: model xxxxxx, type xxxx, trim xx. Valves need to be adjusted per manual. After checking oil level, fresh gas, & spark plug gapped properly, try this, rotate top of engine with both hands clockwise just past hard spot, try cranking. Question: You said you installed a different ignition coil, was it oem? Also holding finger over spark plug hole while pulling starter cord does compression push your finger away?
#3
B
BLM69SS
B
BLM69SS
Mechanic Mark: Thanks for replying. My engine is 123K02-0114-E1. It has fresh gasoline in it and I don't believe it is a carb problem as I have bypassed the carb on several start attempts and never even got it to sputter. The oil level is good. The coil that I put on it came off another mower with a 7 hp Briggs on it and although they don't have part numbers on them it looks identical to the one removed. I used a meter on both coils and I think they are both good the replacement coil ohmed out at 4+ ohms and the original ohmed out at 5+ ohms which I think both are good and both did produce a spark at the plug gap. I didn't gap the plug but it is brand new.
I don't understand what you mean when you said rotate top of engine with both hands? When I hold my finger over plug hole I can feel the push and sucking of the piston.
I don't understand what you mean when you said rotate top of engine with both hands? When I hold my finger over plug hole I can feel the push and sucking of the piston.
#4
bt3
bt3
Mark has a handle on this, but I wanted to chime in.
Because you feel some compression with your finger does not mean you have enough for proper combustion. I suspect valves, compression, proper spark and spark timing, carb and exhaust issues. You stated the Flywheel Key was fine, and that would have been my first goto issue.
I use a hand drill to crank the engine after spraying quick start into the carb if I get a stubborn start issue like you are describing. You can buy or manufacture a bit to go from drill to socket that fits your crank bolt. If I still get no start when cranking with a hand drill, then it's time to go deeper on things like carb setting, valve adjustments and other issues. If it were a 2 stroke I'd highly suspect crank seals.
I had a 4 stroke 12 HP Techumseh Lawn Tractor that appeared to have compression but would not start. Damn near burnt out the starter cranking it for hours. When I tore open the valve covers, I found a piece of carbon preventing one of the valves from closing fully. Removed it and it started immediately.
Please keep us posted.
Because you feel some compression with your finger does not mean you have enough for proper combustion. I suspect valves, compression, proper spark and spark timing, carb and exhaust issues. You stated the Flywheel Key was fine, and that would have been my first goto issue.
I use a hand drill to crank the engine after spraying quick start into the carb if I get a stubborn start issue like you are describing. You can buy or manufacture a bit to go from drill to socket that fits your crank bolt. If I still get no start when cranking with a hand drill, then it's time to go deeper on things like carb setting, valve adjustments and other issues. If it were a 2 stroke I'd highly suspect crank seals.
I had a 4 stroke 12 HP Techumseh Lawn Tractor that appeared to have compression but would not start. Damn near burnt out the starter cranking it for hours. When I tore open the valve covers, I found a piece of carbon preventing one of the valves from closing fully. Removed it and it started immediately.
Please keep us posted.
#5
B
BLM69SS
B
BLM69SS
Guys: I appreciate the responses. A little more information. I had actually forgotten the following till I read another thread regarding a very similar situation with a very similar mower. I had a problem with this mower when it would run for a while and get up to operating temperature and then shut down (as in to empty the bag) When I went to restart it wouldn't restart for approx. 30 minutes till it had cooled down some. I had forgotten because I haven't used the bag for a while and when I did use the mower without the bag I never shut down till I was done with it. So I haven't had to try to restart it when engine was warmed up. This other thread suggested that condition was an indication of insufficient valve clearances.
I did pull the top of the head off to inspect the valves and half suspected to find the intake valve seat not seated. I did not find that condition but what I did notice and I don't know if this indicates something is the following. When the piston was at TDC I noticed that the intake valve was not seated as deep into the head as the exhaust valve. I am guessing but I would say it protruded maybe 1/64-1/32 of an inch higher than the exhaust valve. Is that normal or is that an indication of insufficient clearance or perhaps a seating issue?
I did pull the top of the head off to inspect the valves and half suspected to find the intake valve seat not seated. I did not find that condition but what I did notice and I don't know if this indicates something is the following. When the piston was at TDC I noticed that the intake valve was not seated as deep into the head as the exhaust valve. I am guessing but I would say it protruded maybe 1/64-1/32 of an inch higher than the exhaust valve. Is that normal or is that an indication of insufficient clearance or perhaps a seating issue?
#6
M
mechanic mark
Results this is manual for your engine
https://www.briggsandstratton.com/u...-manuals/single-cylinder-l-head-repair-manual
M
mechanic mark
https://www.google.com/webhp?source...e=UTF-8#q=how to adjust valves on b&s enginesGuys: I appreciate the responses. A little more information. I had actually forgotten the following till I read another thread regarding a very similar situation with a very similar mower. I had a problem with this mower when it would run for a while and get up to operating temperature and then shut down (as in to empty the bag) When I went to restart it wouldn't restart for approx. 30 minutes till it had cooled down some. I had forgotten because I haven't used the bag for a while and when I did use the mower without the bag I never shut down till I was done with it. So I haven't had to try to restart it when engine was warmed up. This other thread suggested that condition was an indication of insufficient valve clearances.
I did pull the top of the head off to inspect the valves and half suspected to find the intake valve seat not seated. I did not find that condition but what I did notice and I don't know if this indicates something is the following. When the piston was at TDC I noticed that the intake valve was not seated as deep into the head as the exhaust valve. I am guessing but I would say it protruded maybe 1/64-1/32 of an inch higher than the exhaust valve. Is that normal or is that an indication of insufficient clearance or perhaps a seating issue?
Results this is manual for your engine
https://www.briggsandstratton.com/u...-manuals/single-cylinder-l-head-repair-manual
#7
B
BLM69SS
B
BLM69SS
Mark: Thanks for the tip. I do have one question though. I went to check my valve clearance. I did this by putting the piston 1/4 inch beyond TDC. I found my valve clearances on the Briggs and Stratton website and as far as I could tell they are supposed to be .005-.007 for the intake and .007-.009 for the exhaust. Well that is not what I have. I measured .058 between the tappet and the valve stem. There was no clearance at the exhaust valve stem. I could see where it appeared as though the intake stem was worn slightly more than the exhaust but I am thinking that kind of excessive clearance would indicate a cam or tappet problem. Opinions?
#8
Fish
Fish
First, you need to take correct valve readings, but before that, you need the crank position to be in the correct spot. There are 2 TDC positions on the crank travel, and you need to take the readings on the correct one. With the head off, and watching the piston/valves, rotate the flywheel, and note when the piston comes all of the way out, on one rotation, when the engine comes up, one of the valves is just closing, as you rotate further, the other valve will start to open. That is the TDC that you do not want, go around again and find that TDC, and take your valve readings.
If you now find one of the valves with no clearance now, then you have dialed in on your problem.
If you now find one of the valves with no clearance now, then you have dialed in on your problem.
#9
Fish
Fish
If so, your block has overheated and warped away, and the valve's clearance went away as well.
#10
B
BLM69SS
B
BLM69SS
Fish: Think I know how to find TDC on a four stroke engine. There is only on TDC on a four stoke however there are two occasions that the piston is at the top of its travel. Anyway it was 1/4 beyond TDC which I believe is the correct position to read the valve clearances and they are as I reported them. I did find a bunch of grass packed under the flywheel/blower housing. It is possible that it overheated.
#11
Fish
Fish
Well I have to ask. If you are sure, then you need to adjust that valve into spec.
To repair the engine correctly, it would require a complete correct "valve" job, which most of the gang here have never witnessed.
But if you adjust your valves back into specs, you will likely get her running again for a while!
To repair the engine correctly, it would require a complete correct "valve" job, which most of the gang here have never witnessed.
But if you adjust your valves back into specs, you will likely get her running again for a while!
#12
M
mechanic mark
Correct position for valve adjustment is 1/4" past TDC, not 1/4 turn, you may already know this as well as engine cold.
M
mechanic mark
Fish: Think I know how to find TDC on a four stroke engine. There is only on TDC on a four stoke however there are two occasions that the piston is at the top of its travel. Anyway it was 1/4 beyond TDC which I believe is the correct position to read the valve clearances and they are as I reported them. I did find a bunch of grass packed under the flywheel/blower housing. It is possible that it overheated.
Correct position for valve adjustment is 1/4" past TDC, not 1/4 turn, you may already know this as well as engine cold.