Fixing Briggs and Stratton lawn tractor

[paul_d_demott]

I have an older Sears Craftsman lawn tractor with a 180 opposed twin cylinder Briggs and Stratton Engine. My son was cutting the lawn with it the other day and it gradually stalled out on him. He started it up again, but it quickly stalled out again. Now the engine will barely crank and will not start.

I checked the battery with a multi-meter and it tested at 12 volts. I tried jumping it with a portable power source and this did not help. I tried a new on/off switch and this did not help. I removed the cover and I can turn the flywheel by hand without difficulty. The oil level appears to be ok.

Any suggestions of what I should do next. I don't have much experience with engine repair, but due to the tractor's age I don't think it would be worth taking to a repair shop. So I willing to take a shot at home repair.

From what I've read I am thinking the starter engine might be the problem. One internet source suggested jumping the starter directly from the battery. I am willing to try this, but it appears on my mower that I need to first need to remove the flywheel to get to the starter and this looks like a major undertaking, especially given the age of the engine. Is the starter where I should start or are there other things I should or could check first? One question I have is whether a problem in the starter would have caused the engine to stall out after it was already going?

Any other suggestions on how to troubleshoot this issue? I do have a basic Briggs and Stratton manual for the engine on a CD-Rom, but it does not contain alot of trouble shooting info (at least that was helpful to me) on the starter/electrical system. It is helpful, however, on assembly and disassembly issues.

[Oren]

You might try to tighten/clean the starter/battery/solenoid cable(s). The engine will run if it has essentials: fuel, oxygen and fire (spark)...... Try the web site for B&S.

I have seen a wet blade of grass short my mower when it landed right on the plug wire and head...pulled if off and fire back up.

-- Oren

"Well, it doesn't happen all the time, but when it happens, it happens constantly."

[Rich256]

From what you describe it is either the starter or battery. Be real certain it is not the battery or the starter solenoid before going to the starter. You need to measure the battery voltage when trying to crank the engine.

When you say you jumped with a portable power source are you certain it had a good charge. Jumping from a car battery would work too.

I have to kind of lean towards a weak battery because what you said about the engine stalling out. A bad starter would not cause that.

[Mr.E]

Several things come to mind:

The starter should not be able to cause the engine to stall. Stopped inline fuel filter. This engine uses a vacuum driven fuel pump. Check for vacuum hose leak or fuel pump malfunction. Check plugs- this engine fires plug to plug. Put 6 or 8 drops of gas down the carb throat. Replace air filter and see if it fires. Have seen the electric blade clutch bearings fragment and lock the engine as soon as it tried to rev up. Love my old 18 horse clunker.

[mm]

Can't solve your problems but a few things:

A fully charged battery is about 12.6 volts. Of course yours is not fully charged, but you could charge it. Voltage stays near 12 volts even while a battery is 80% discharged. I forget the math, but it makes sense.

So the ohter guy is right, that you have to measure the voltage while you're trying to start the mower. I think it should be at least 11 volts then, but I only have experience with cars, with much bigger engines.

If you are going to clean the battery cables at their ends, remove them at each end and use a knife or something to scrape them shiny. I had a car that, every time I left the lights on and ran the battery down, wouldn't start even with a jump. First I had to take the battery cable off the solenoid and scrape it clean, then put it back on. Later I learned that when it wasn't too tight I could reach my arm under the car and just twist the cable on the solenoid bolt about

20 degrees, but I only recommend that when your dressed up and on your way, like I was.

The cranking switch? If it cranked a little bit when it was bad, obviously that switch was good. Also you could have saved a new switch, unless you had it already, by using a wire with alligator clips on each end. Just bypass the switch. Radio Shack has a bag of

1. Worth every penny, 5 times every penny.

I removed the cover

I really doubt that. Are you sure it doesn't bolt on at the side, after slipping up inside the flywheel.

No. So that's what makes it seem like the battery is weak, maybe just needs a charge or a jump. I would jump from the car. You won't run out of juice, especially if you run the car occasionally.

Like any starter, don't crank it for more than a couple minutes at a time or it will get too hot.

What's wrong that made the engine stall is another question. Maybe it will be fine when it is cold. Check spark plug that it's not fouled.

[Ether Jones]

How old is "older"?? What is the model number of the engine? This info should be on a nameplate or label somewhere on the engine. There are different versions of the 180 opposed twin Briggs engines and they have different ignition systems etc. (Mine is the 16.5 HP with electronic ignition - no points).

Well, if the engine will barely crank, then you've obviously got a problem with your battery or your starter motor or your cable connections or engine friction. BUT... it's difficult to say, without more detail from you, whether this is a CAUSE or an EFFECT of the original stalling problem. In other words, your son could easily have worn out the battery cranking the engine trying to get it started, because there was something else wrong with the engine.

It is a very common problem, especially with kids, to abuse the starting system on lawn tractors. They are not designed to crank the engine for long periods of time. You should never crank the engine for more than 5 seconds at a time. If the engine does not start within

5 seconds, turn the key off and wait 10 seconds before trying again. If the engine doesn't start after 3 or 4 tries, FIGURE OUT WHAT'S WRONG before you burn out the battery.

If the engine doesn't crank when you turn the key, RELEASE THE KEY IMMEDIATELY. Wait 10 seconds and try again.

The first thing you need to do is fix the cranking problem so that you can perform further troubleshooting.

Simply placing a voltmeter on the battery terminals with no load on the battery tells you nothing. Even a "dead" battery can read 12 volts with no load.

Place the voltmeter on the battery terminals and observe the voltage when someone is cranking the engine. If the voltage drops below 9 volts you've got a problem. Do you have a battery charger? Charge the battery overnight, and try cranking the engine again in the morning.

Post again after you've tried this.

Please give more details on exactly how you did this, and what kind of "portable power source" did you use.

Highly unlikely.

[Rich256]

Yeah, voltage is not a good way to measure state of charge. Use a Hydrometer.

State of charge/voltage (at 80F):

100% = 12.65 75% = 12.45 50% = 12.24 25% = 12.06 0% = 11.89

[Stubby]

Ditto. My chariot is 17 years old.

Try some "Starter Fluid" from an auto parts store. It's ether and will usually start an engine. Replace the fuel filter. I had a car that would stall out going up steep hills or going at 70 mph for a few minutes. The problem was the fuel filter was letting only a trickle get through to the carburetor; consequently, the car would die after the fuel in the bowl in the carb was used.

[Ether Jones]

True, except the OP said the engine will "barely crank". Ether may not start an engine in that condition. He needs to fix the cranking problem first.

The carb on the Briggs 180 opposed twin L-head engine is extremely sensitive to contamination. Use utmost care if you decide to replace the fuel filter. Use a toothbrush and a vacuum cleaner to clean the locations you intend to disconnect. Then spray with WD40 and wipe with clean lint-free cloth. If you replace the fuel line, be absolutely certain the new fuel line is clean inside. There may be manufacturing debris inside it. Use a flashlight to inspect. Hold the flashlight on one end, and look through the other end. If you see any debris, rinse it thoroughly with kerosene or mineral spirits before installing.

Parts for many Briggs engines can be found in the garden center of WalMart, since WalMart sells MTD tractors which use Briggs engines. You can buy spark plugs, air filters, fuel filters, oil filters, blades, and belts there.

[paul_d_demott]

I have not gotten the mower starter yet, but I think I am getting closer to finding the problem. Here is an update: First, Ether Jones asked for the model number. It is 422707. It is a 1993 tractor. Second, many of you suggested that the problem might be a weak battery. I took the battery to the local parts store and they tested it under load. The battery was partially discharged. They charged it up again and tested it. The battery tested ok When I reconnected the recharged battery, there was improvement. Before, the engine just barely cranked. Now it is cranking better, but still weakly. In fact, it was sufficently weak to cause me to think that the problem is still with the electrical system/starter system as opposed to a fuel problem. The person at the parts store suggested that I run a test by attaching the negative battery cable to the battery, but before connecting the positive cable, I should put one prong of the multi-meter on the battery post and the other on the positive battery cable. I did this. The multimeter showed a volts reading of about one-half a volt. I understand that a non-zero reading means that there is a short somewhere in the electrical system. Is this likely where the problem is? If so, how exactly do I locate the short. I am thinking that I need to disconnect parts of the wiring one by one until the multimeter reads zero. When this happens, the disconnected wire would be where the short is. Is this right? If so, where should I start? Also, one reply suggested that engine friction might be the problem or a contributing problem. I can turn the flywheel by hand. Is there a way to determine whether the friction is excessive or is this something mechanics just have feel for through experience? It did not feel excessive to me, but I don't know how turning the crankshaft would feel on a new engine. I appreciate everyone who has left comments. I have found them to be very helpful. I am hopeful that with a little more help, I can get this thing fixed.

paul_d [e-mail] wrote:

[Ether Jones]

You have the same engine as I do, only quite a bit older. Mine has electronic ignition, but yours probably has a mechanical ignition system (points and condenser). Please provide the Type and Code numbers as well. They should be on the same label.

So, put your voltmeter across the battery terminals and tell us what the voltage is while the engine is cranking. Re-post when you have this info. I hope you haven't cranked it so much that you've worn the battery down again.

You say "the" problem. It is likely that you have more than one problem.

Your original problem was that the engine was running but then stalled. This probably has nothing at all to do with your slow-cranking problem.

Disconnect the wires and remove the spark plugs. Try cranking the engine with the plugs removed. It should crank quite fast (because it's not fighting engine compression). Re-post after you've run this test and tell us the results. If it does not crank fast, you've either got a bad starter motor, or bad cable connections, or a serious friction problem in the engine. (Or a bad battery, but you said the person at the parts store tested it).

No.

You probably don't have a short.

run the test above with the spark plugs removed.

[PaulD]

Ok. Here is some more information:

1) Model 427707; Type 1522 01 Code: 9301235B

2) I cranked the engine with the multimeter touching the positive and negative battery posts. The volts dropped to a little above 10 volts.

3) With the spark plugs removed, the engine turned rapidly.

I appreciate your expertise. What's next? Thanks

Ether J> > I have not gotten the mower starter yet, but I think I am getting

[PaulD]

[John Lawrence]

[Ether Jones]

Top-posting makes it quite difficult to discern the context of your query. What does the pronoun "this" refer to?

[Ether Jones]

Your engine was manufactured January 23, 1993 in the same facility where mine was made.

Judging from the Type number, I think you have electronic ignition, not breaker points (this is a Good Thing).

Well, the battery appears to be OK.

The rapid cranking would seem to rule out a friction problem in the engine.

It's still possible that you have a bad valve but let's set that aside for the moment.

The most likely cause of the slow cranking would seem to be either:

- a bad starter motor, or

- bad connections in the cables between the battery and the starter motor.

By the way, when you removed the plugs, what did the tips look like? Were they a light tan and/or gray color with no evidence of cracking or corrosion, or were they black and/or cruddy and/or corroded? It's worth the small expense to go ahead and replace them with new ones if there's any question.

I'd suggest checking for bad cable connections first. To do this, re-install the spark plugs before proceeding.

You want to check the circuit going from the battery to the starter motor (and back) looking for a bad connection. You can detect a bad connection without taking anything apart by using your voltmeter. A bad connection will have a voltage drop across it when the engine is cranking. A good connection will have very little or no voltage drop across it. The voltage drop is caused by the current pushing through the resistance in the bad connection (V=IR).

Proceed as follows: The starter motor on this engine has only one electrical terminal - the positive terminal. On my tractor (White equipment), it is easily accessed without removing anything. Put one voltmeter lead on this terminal. Touch the other voltmeter lead to engine ground (cooling fins would be a good choice). Make sure the voltmeter leads are making good contact. Have a helper crank the engine, and check the voltage reading. It should be the same as the reading you got when you had the voltmeter across the battery with the engine cranking:

- If the voltage IS the same (and 10 volts or greater), it would normally indicate that your starter motor has a problem since it's getting the proper voltage but isn't cranking properly. But... this wouldn't explain your original problem why your engine stalled. So... was your engine happily cranking just fine until this stalling problem occurred? If so, it's probably not the starter motor - you may have a bad valve. This can be tested but requires compression gage. Post again when you get this far.

- If the voltage is NOT the same, then you have a bad cable connection somewhere. Hopefully this is all it is. Post your results when you get this far and we'll go from there.

If you can't access the starter motor terminal, you can at least easily check the ground half of the circuit. Re-post and I'll tell you how.

[PaulD]

[John Lawrence]

[Ether Jones]

The reader has no way of knowing what you meant since top-posting removes the connection between your pronouns and their associated nouns. That's one reason why most usenet users dislike top-posting.

Please re-read the post. Fuel filters and carburetors have nothing to do with the cranking problem. They may, however be related to the stalling problem.

[Ether Jones]

Was the engine cranking strongly right up to the point when the stalling episode occurred, or was the cranking speed deteriorating slowly over the period preceding the stalling episode?

This can be a sign of a weak battery, or bad cable connections, or a starter motor starting to go bad. You said you had the battery checked out, so I will assume they checked it properly and it is OK. The troubleshooting procedures mentioned in the previous post should help isolate it to either a cable problem or a starter problem.

However, as long as you have the plugs out, you should try one more thing to help eliminate another possibility (valve problem). Make sure the plug wires are far away from the spark plug holes and well grounded so that there are no sparks. Have a helper crank the engine, and put your thumb over each spark plug hole. You should feel alternating compression and suction in each hole, and they should feel the same. If they feel different, or you don't feel both compression and suction, you've got a more serious problem inside the engine.