I have a Murray lawn tractor with a 18.5hp Briggs & Stratton.
The engine will turn over, but won't start. When it is "turning over" it will intermittently emit a loud high pitched "grind-squeak" noise (ouch) . The engine is also leaking oil- quite a bit. The floor of the shed underneath the tractor was covered with it. I would like to try to fix it as I cannot afford to buy anything at this point and I do have the time to spend right now.

Based on the symptoms- what are some of the likely things I will be facing and where should I start?

I do have the B&S repair manual which shows part explosions, etc. I have done smaller things like rebuilding carbs and such but nothing of (what I expect) this magnitude. Thanks for any advice.

Has the frame anywhere close to the engine have oil on it??
Does the stack pulley (under the engine) have oil on top of it???If so sounds like that's coming from the bottom oil seal of the engine.

Reply back with modle and type numbers and someone will be able to look up the part numbers that you'll need.

As far as the noise sounds like the starter motor is going out,or needs to be taken apart and cleaned out.

Thanks- OK from the plate on the engine:
Model: 42A707
Type: 2653E1
Code: 97122085A

Any help with part numbers is appreciated!

Ok,the part number for the PTO (bottom) oil seal is 291675.All you have to do to replace it is drop the front of the deck.drain the oil.Take the 2 belts off the top side of the stack pulley.Take a 5/8 scoket with small extendion and take off the bolt holding it to the crank.CAREFLLY slide stack pulley off the crank.Dig out old oil seal with screwdriver,then tap new one in place (being sure to get it straight)

And if you need the oil pan gasket the .015 gasket part number is 92292

You'll be basy for bout an hour.

GOOD LUCK

translation = 3 hours

Seriously though- thanks for the advice.

I also see that there are several listings on eBay! for the starter. You think that is what is making that intermittent screech noise when cranking...? Is it worth trying to do anything with my starter ( you mentioned "cleaning") or should I just pickup a used one for about $30-40 which seems to be the going rate on the auctions.

Also, I see through your post that PTO means "bottom" but what does the PTO stand for. I see that reference throughout the B&S manual.

Thanks again!

PTO stands for Power Take Off I do Believe

:wave: bsman is right PTO does stand for Power Take Off.

And for your starter :
I've had plenty of success just cleaning and rebuilding them.
There's a bushing at the top,pressed into the braket (the cap drive) the part number is 696967 incase yours is walowed out.

The bottom plate (with the brushes inside,and another bushing) is part number 691293.Again if needed.

Shinny (glased) brushes in an eletric motor of any kind will cause one not to opperate fast as it should.You can just buff these off with a piece of sandpaper.

But you mentioned getting one form Ebay for around $30.00-$40.00,maybe that would be best since the bottom plate itself costs around $28.00 by itself.

I haven't had a chance to work on this in the last week. I have gotten a new seal but have not put it in yet. I have noticed some other issues I wanted to ask you about on this same mower. #1. Put a compression gauge on both cylinders and have zero on both cranking the engine about 5 or 6 spins. #2 Pulled the spark plug and grounded it to the engine. Cranked the engine over- no spark. Suggestions?

Those are two rather unrelated symtoms. Are you sure the engine is turning over or is the stater bendix shot and the motor is just whirling away. I have been very fortunate over the years concerning starters.For a noisy starter, I have always been able to get by dissassembling them and putting lubriplate or chasis grease on the bushings works good if , as as the other reply said, the bushing is not worn badly. A dry bushing is a sickening sound.

Good question. No, the engine is spinning so I assumed it was turning over. I didn't know there was a difference in all honesty. So if the starter was shot I would have no spark or compression? All roads seem to lead back to the starter.

If the engine's spinning at what seems a normal speed, your motor and bendix should be ok.

If the engine is turning past its compression stroke, you should be getting compression - if not, check plug threads, bore, rings and head gasket. Also check if you've got a stuck valve. I think on this engine the coil and alternator are seperate, so by operating the starter it shouldn't suck the ignition dry of power. Check the coil for continuity with a multimeter and try cleaning the points or re-adjeusting them.

As for the noise, see if the bolts that hold the ignition coil on have come loose and are allowing it to move around, pulling it in contact with the flywheel when the magnet whips round. I had a Briggs with this fault, and it sounds unbelievably bad like the engine's about to die, but it's only minor!

Thanks for the info. I think I mis-interpreted what Tom was saying anyway. In re-reading his post I now realize that when he said "motor is just whirling away" he meant just the starter motor and not the engine. Yeah- the engine is spinning what seems to be normal speed, especially after I put the new battery in. I am going to go back to square 1 and start by getting a book on how small engines work. I am determined to get this running but I have read so much stuff that now I feel lost. The bottom line is this:
1.) The engine will turn over at normal speed but won't start. Not even for a second. It has fresh gas, new plugs, a new fuel filter, a clean carb, a new battery. It hasn't run this year. It died while mowing last fall, however it was not as a result of hitting something. As I recall I heard something like a "clunk" in the endine area and then it quit. At that point, the starter just hummed/clicked and didn't crank the engine. When I took it out for the first time this year- it cranks the engine but won't start. It does emit an intermittent squeal when the engine is cranking- but "seems" to crank the engine at the same speed it always did.
2.) If I pull the plug(s) out, leaving the wire connected and press the threads against the cylinder head and crank the engine- I see nothing, no spark.
3.) If I spin the flywheel backwards, with the plugs installed I get no rebound. Using a compression gauge I get zeros on both cylinders cranking the engine 5x.

It seems like the whole thing is completely AFU. Either that or it is something totally stupid that I may never find on my own. I had used this mower for 8 years so I am pretty familiar with what needs to be in what position to start and have never had a problem with it before it died.

:( Sigh- well just wanted to summarize, in case something stands out that may cause a revelation (for someone else- obviously not for me!).

Thanks again for the help to this point.

Best thing to do if you're serious is to take the heads off and check the bore for scoring. And see if you have a stuck valve or blown head gasket.

OK- I get do that easy enough (get in there),
1.) What am I doing when I check the bore for scoring. What are the telltale signs?
2.) I have never seen a blown head gasket. When a head gasket is blown- is it obvious? What am I looking for when I pull them off.
3.) I am thinking a stuck valve would be easy enough to determine once I get in there (even for me.)
Thanks.

Telltale signs of scoring are large, deep scratches down the bore. As a rule, if you can dig your fingernail into it, its too deep! The head gasket is a sealing paper or metal ring which seals the gap between the head and the block. If its blown, you'll see a gap in it or "blast marks" going from inside out, where the gases have been escaping.

I was just reading though some information on the tractor itself. The tractor has three switches which I believe are kill switches. One is under the seat, one is on the arm that activates the blades and one is on the brake pedal. If one of those switches was all of a sudden went bad (open) would that cause "no spark" or would the engine typically not even crank over in that case?

Thanks. Let me ask you this. My tractor has three switches (kill?) . One under the seat, one on the blade lever and one on the brake. What if one suddenly went bad and was stuck open? Would that cause the no-spark condition? Here is a link to the wiring diagram which probably has the answer- if you know how to read schematics.

http://img355.imageshack.us/img355/8220/46570x8a5ui.gif


Oops- I didn't think I had posted already- sorry! :rolleyes:

If any one of the switches was stuck closed (shorting the HT lead to ground), there wouldn't be a spark and the starter wouldn't operate. The switches are all dual-pole dual-throw - one side of the switch shorts out the HT feed when it's in the "up" state, e.g. no-ones on the seat, and the other side disconnects the starting circuit so the solenoid won't operate.

So if the starter's working ok, it means all switches must be good. Don't forget that there could be a loose/broken connection or a broken spade connector.

So if the starter's working ok, it means all switches must be good. OK, That answers that.

Don't forget that there could be a loose/broken connection or a broken spade connector.
Please explain. Are you saying that a loose/broken connection or a broken spade connector (?-where is that book again?) COULD cause no spark even though the starter is turning the engine?

I also noticed something else. If I turn the flywheel by hand it sounds and feels like the underside is scraping. Is that normal. I know there should be some resistance but "scraping"? I need to get my hands on a puller which is the only reason I haven't taken it off and looked underneath at the key yet.

OH Ohooo!!!! Wonder if you had a connecting rod let loose. I saw one like this on a generator that my boss had me work on about a month ago. It was locked up solid. I moved the flywheel backwards slightly and it must have cleared the crap away from the crank. Then I could spin the crank but the piston didn't move. First thing to check once the heads are off is to see if the pistons will move when you rotate the flywheel.

Anywhere along the line there could be a broken wire which is shorting to ground and preventing a spark. Follow the wire from the HT coil right round and through all the switches, making sure that nothing is shorting through.

Or, just unplug the HT lead from the back of the keyswitch (number 3 on the diagram) and check for a spark then. This will mean that nothing is there to kill the engine, it just goes straight from coil to spark plug.

The scraping could be a melted-down stator ring, which I have seen happen. It shorts through and melts itself into a nasty mess - this has nothing to do with the spark though, since this is totally seperate.

Or, just unplug the HT lead from the back of the keyswitch (number 3 on the diagram) and check for a spark then. This will mean that nothing is there to kill the engine, it just goes straight from coil to spark plug.

Ok- so if I understand you correctly, I can pull the yellow wire off of the keyswitch (diagram) and then check for spark. If I have spark then, I have a short somewhere and then I will need to find where.

Thankfully Little League is nearly done and I will have the time to spend on this soon! :tongue:

I took the heads off. When I turned the flywheel nothing happened. Neither the pistons or the valves moved. I pushed the pistons into the cylinder by hand to see if they would move- they did and now they are seated all the way in. Now the flywheel will only turn to a certain point and stops in both directions. What has happened to this? :confused:

Yeah......I'd take the engine out and actually pull the sump off and check... but it REALLY sounds like you threw both connecting rods... any metal shavings in the oil? or have you checked?

Yup, I think somehow both connecting rods sheared too. That grind-squeak sound you described is probably the metal shavings working their way into the bearings, camshaft etc. Not good!

Its turning to a certain point and then hitting the stump of con-rod I think.

I am thinking I am going to punt at this point. I just wanted to say thanks to all who have offered advice- I have learned much. I am certain that lack of routine maintenance has brought me to this point. Hopefully others who read this will see that too. :(

Yeah..... sometimes you can rebuild em, but if anything on the block was damaged, usually leaves cracks everywhere (not good) see if you can find a good used one, be alot cheaper then a new mower or engine.

Funny you should say that- what is your opinion on this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7776446625&ru=http://search.ebay.com:80/7776446625_W0QQamp;sspagenameZhQ3ahQ3aadvsearchQ3a USQQcatrefZC5QQfclZ3QQfromZR7QQfrppZ50QQfsooZ1QQfs opZ1QQnojsprZyQQpfidZ0QQsacatZQ2d1QQsofocusZbsQQfv iZ1 (http://www.qksrv.net/click-1606754-5463217?loc=http%3A//cgi.ebay.com/ws/eBayISAPI.dll%3FViewItem%26item%3D7776446625)

I live in the same town, its close. Worse case scenario, would I be able to put this engine on my existing tractor?

I've rebuilt smaller engines which have sheared conrods, but depending on what speed the conrod went at, it screws the whole block up, esp. the bearings.

Something must have seriously let go to cause both conrods to go, so its best to get a new engine. I'm not sure if that one on the tractor would fit, but being a briggs I guess it would.

That engine is well worth more then that alone in good shape.... I'd get it, keep the mower itself for spare parts.