# 16 HP Briggs single won't start



## Midnite Tweeker (Jan 30, 2014)

Model #326431 Type 0228-01 Code 7809291

Installed on an old garden tractor and used to run a 42" snowblower. It was winterized and parked last spring in running condition. This winter it refused to start. It has always been difficult to start the first time in winter, so this wasn't unusual. What is different this time is that after 33 years, this time I can't get it going. Electric starter with a trickle charger on the battery. Block heater on the engine.

Initial symptom was no spark. Polishing the points with a piece of cardboard, which usually works, didn't help. New points and condenser didn't help. Finally replaced the magneto coil and now have a good spark with the plug removed and laying on top of the engine. Plug screwed in it refuses to even pop.

Gas is fresh and treated with Heet. Pulling the high speed needle lets the bowl drain and fill with fresh gas. Spraying ether either into the carb or into the sparkplug hole doesn't get a pop. Dumping a tablespoon of gas into the sparkplug hole doesn't get a pop. Warming the sparkplug with a torch doesn't help. 

Extended cranking usually results in gas slowly dripping out of the carb. It still does this. Extended cranking also used to eventually result in heavy grayish vapor coming out of the muffler and then eventually it would begin to pop. This time there's no obvious vapor coming from the muffler. I'd suspect a carb problem, but putting gas/ether directly into the sparkplug hole seems like it would at least get a pop or a short run, and there's nothing.

I'm wondering if the flywheel key sheared and the timing got hosed, but it ran OK when it was parked last spring. Nothing I've done should have affected the key.

Ideas? The lane is 1/4 mile long, and I really, really need to get the blower working again. Thanks. 

MT


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## Vegassparky (Nov 24, 2013)

Are you sure you have compression? Pull the plug, crank the starter for a few revolutions to clear out that cylinder, and add a few drops of motor oil into the spark plug hole. Then quickly reinstall the plug, and use a little starting fluid at the carb inlet to see if it fires.


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF

If you have fuel, spark and compression it will fire.

You had the flywheel off, how was the key way ? Are you sure it did not fall out when you put the flywheel back on ? I assume you got the points gap correctly.

Look in spark plug hole and see if you can see the valves moving up and down.

BG


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## Midnite Tweeker (Jan 30, 2014)

Basementgeek said:


> Hi and welcome to TSF
> 
> If you have fuel, spark and compression it will fire.
> 
> ...


No, I did not have the flywheel off. The points are on the side of the engine and the flywheel did not need to be removed to replace the coil. 

I've adjusted the points gap everywhere from "they never close" to "they never open" and everywhere in between and it makes no difference. It never so much as pops or sputters.

I originally had thought to stuff nylon rope into the cylinder via the sparkplug hole to prevent crank rotation while I wrenched on it. That's when I discovered that the sparkplug hole did not open directly into the cylinder. Probing into the hole with a rod I did determine that I could touch at least one valve that moved up and down. I'll take a flashlight with me tomorrow & see if I can see both of them.

I also layed the loose sparkplug with its wire across the sparkplug hole to see if any vapor would be pumped out that might ignite. Nothing, although the sparkplug was repeatedly lifted an inch above the hole by the blast of air being pumped out.

MT


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## Midnite Tweeker (Jan 30, 2014)

Vegassparky said:


> Are you sure you have compression? Pull the plug, crank the starter for a few revolutions to clear out that cylinder, and add a few drops of motor oil into the spark plug hole. Then quickly reinstall the plug, and use a little starting fluid at the carb inlet to see if it fires.


I'm not sure of compression, but I have layed the loose sparkplug with wire across the open sparkplug hole in an attempt to ignite any vapor that might be pumped out. Got nothing, although the plug was tossed up an inch into the air by the blast of air rushing out of the hole.

I'll try adding some oil to the cylinder tomorrow. 

I have to admit this really has me stumped. I've been fiddling with this a couple weeks, having been down the path of first installing a Magnetron (in an attempt to join the 21st century), then discovering that the flywheel magnet would need to be repolarized in order for the Magnetron to work, then removing the Magnetron and re-installing the old coil but with new points and condenser, then discovering that the new points had a manufacturing defect that shorted to ground, then replacing the new points with the original points (which were still in good condition) but keeping the new condenser and still having no spark, and then finally installing a new magneto coil which ultimately restored the spark. 

In the past, a little oxide on the points from summer humidity would result in no spark until I burnished them with cardboard. But soon as I did I could always see a tiny bit of arcing at the points which always produced a spark at the plug, and then the engine would always start. So when the new coil produced a nice fat spark I figured things would be running shortly. Since then I've been fooling with it for most of a week and it has yet to even pop.

MT


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## Basementgeek (Feb 7, 2005)

Just an FYI, a park plug what fires in free air may not fire when it is installed and under compression. We are using a new plug correct?

Your points need to be set to .020. That setting is important. Air gap on the coil and flywheel at .010. 

Really need to check those valves.

Not much info that engine. It is pretty old. Not many engines that have external points.

BG


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## Midnite Tweeker (Jan 30, 2014)

The plug is new. Looking down the plug hole I could only see one valve, the intake, and it was almost directly under the hole. Gauging from the location of the exhaust pipe, the exhaust valve is too far off to the side to see. 

I was going to try putting oil into the cylinder as suggested, but the cylinder was off to the other side and not visible. I'd have needed a small hose or something to get through the hole and over to the cylinder. In the end I gave up because oil would have taken forever to flow through a tube that small (it's cold), and I didn't want to dump a large quantity of oil into the hole just to get enough that would finally overflow into the cylinder.

Instead, I grubbed around until I found a 50-year old cheapo compression tester and gave it a try. It showed 95 psi, which is right at the low end of the "green" range of OK. The fine print says this equates to an approx. 8 to 1 ratio. It may be low, or it may be about right for a 1978-vintage engine that's never been overhauled. Either way, it should be good enough to run.

But once again, after dumping a couple Tbs of fresh gas into the hole immediately after verifying a good spark on a new plug, and cranking a warm engine with a topped-off battery...not so much as a pop. sigh......

I'm out of ideas other than the possibility of a sheared flywheel key. I've removed the grill from the tractor, the snowblower drive pulley, the starter drive belt, the perforated mesh debris shield, the stubby adapter shaft, and the large crankshaft pulley. Down to where the next thing to come off will be the flywheel. 

I have a puller but the flywheel has never been off, and I've never removed one before. Plan is to attach the puller, screw in the center screw until it develops enough tension in the puller to produce some deflection, and then tap it with a hammer. Does that sound about right?

MT


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## Midnite Tweeker (Jan 30, 2014)

Well, crud. 

Ended up needing to warm the flywheel with a propane torch but then one or two whacks on the puller screw and the flywheel jumped an inch or two. Piece of cake. Eagerly pulled it off nearly certain I'd find a sheared key.

Except that there was nothing wrong with the key.

So other than adding one more item to the list of things that aren't wrong, I'm no closer to figuring out what is. I mean, what's left? Other than removing and re-installing the idle and high speed screws in the carb and draining the float bowl I haven't ripped into the carb yet. But putting a little gas or ether directly into the carb or cylinder should have pretty much bypassed the carb if it was the problem, right?

MT


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## SABL (Jul 4, 2008)

I'm not getting a clear look by viewing the parts diagram......:sigh:

Does your engine have an updraft carb?? How's the integrity of the intake system?? I see a manifold with a gasket at each end......any chance it is 'sucking air'?? Check to see if all bolts are tight and the gaskets are intact.


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## Basementgeek (Feb 7, 2005)

SABL - It is still would fire as they are putting gasoline in the spark plug hole.

Is the spark kind of blueish white? Points set right and working.

Magnets in flywheel still pretty strong ? Air gap between flywheel and coil at .010.

I am out of ideas. Maybe one of the parts you bought are defective

Let us know what you are able to figure out please.

BG


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## SABL (Jul 4, 2008)

3 Tbsp of fuel is a bit much. It's the vapor that ignites, not the gas. 

But I agree with BG......something should have sputtered by now.


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## Vegassparky (Nov 24, 2013)

Fuel directly in the plug hole will be too much. I'd shut off the fuel supply to the carb, crank it while paying attention to exhaust pressure. Then a little carb cleaner on the air filter, choke it down, and crank it again. If you have no signs of combustion, I'd keep digging for an ignition problem. If there's a low rumble, I'd go for carb/induction problem. Sometimes the difference can be very subtle with a stubborn motor. Cold temps won't help troubleshooting. Are you working on this in a garage?


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## Midnite Tweeker (Jan 30, 2014)

Unheated machine shed (groan.) But a block heater on the engine, brooder light on the carb, trickle charger on the battery. I finally pulled the float bowl off of the updraft carb, not because I really thought this was the problem---gas/ether into either the carb or the sparkplug hole should have bypassed a carb issue, at least temporarily---but it would add one more thing to the list of items I've checked. First time the float bowl has been off since I bought it new 34 years ago. You could have eaten off of the bottom of the bowl. No sediment or jello. Pulled the high speed needle and jet & shot carb cleaner through the jet. No plugged holes. 

Back together and cranking---nothing. Gas/ether in the plug hole, in the carb, choked/not choked, good spark w/plug out of the hole, but almost like there's no spark when the plug is in the hole. (BTW, I'm only screwing it in finger-tight due to all the in and out.) Kind of like the light in the refrigerator---how do you know the light goes out when you close the door? 

Dug out an old timing light that goes between the sparkplug wire and the plug. Cranked the engine with the plug out---the light flashed. Screwed the plug in---the light still flashed.

Extended cranking (at least 30 secs) while choked and then looking into the sparkplug hole shows wetness. A couple secs of cranking with the plug out blows the wetness away.

Today I was completely out of ideas. Because the new plug is bright and shiny it's hard to tell if it's wet, so I dug out the old grayish tan plug because wetness shows better. Checked for spark lying on top of the engine. Healthy looking spark. Screwed it in. Then for a twist I dumped about 1 Tbsp of Coleman gas into the carb and gave it a crank. Within 5 secs it fired but died! I nearly fell over. It's only been 2 months of fiddling and this was the first pop. Cranked it again & it started and sat there idling. Let it run for a couple minutes, shut it off a couple minutes, and then re-started it. No prob. I needed to stand there and sniff exhaust fumes to actually believe it.

I'm at a loss. The plug I replaced was brand new. It sparked when sitting on top of the engine. Using the timing light it seemed to spark when it was screwed in.

The Coleman fuel has to be over 20 years old, but stored in a metal can all that time. The most recent batch of ethanol gas I was using came from the pump a couple weeks ago. Theoretically fresh. In a white plastic container it had a pale yellowish color. Last time I paid any attention to the color of gas it was pale pinkish orange. Probably pre-ethanol. The reason I tried Coleman fuel is because, as I drained the float bowl, I got gas on my fingers and evaporative cooling on my skin didn't feel quite as bitter cold as I remembered from years ago. Like the gas wasn't as volatile. Yet this is the "same" gas I've been using in the engine for years, regular with 10% ethanol, that is.

I'm in the process now of getting everything back together which will take a couple hours. Just in time---more snow in the forecast tomorrow.

I mentioned above that I had gotten new points with a manufacturing defect that took a while to track down. Now I'm wondering if there was something wrong with the new plug, too, though what it might be I can't imagine. For now, I left the old plug in place. Getting this thing running is way more important now than playing detective.

Thanks for all the comments, and if you've got any insight into what happened here, I'm all ears. This has gotta be some kind of fluke, but darned if I know what to blame it on.

MT


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## SABL (Jul 4, 2008)

Hi MT.......:wave:

I've got exactly what you have at this point.......theories. 

Plug could be defective. I had a friend back in the day (60's) that had a Honda CB160......2 cylinder. Out of the clear blue it would lose power....I was riding on back one day when it happened. He'd pull out a perfectly good looking spark plug and replace it......problem fixed. For some reason the plug would just fail.

Gas......what octane?? Higher octane is harder to ignite but packs a punch......I'd try a lower octane (if you aren't already using 87).


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## Basementgeek (Feb 7, 2005)

Like I said in post #6, a plug fires differently under compression than free air. (I have a spark pug tester that puts them under pressure)

I have never had a bad new plug, but they do make them I hear

Glad you are making progress :>)

BG


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## Midnite Tweeker (Jan 30, 2014)

Yesterday, one day after finally getting the engine running, I got everything reassembled. Time to fire it up again. Still on trickle charger, heat lamp and block heater. Same old well-used plug as the day before. Cranked with and without ether---nothing, not even a pop. Again dumped 1 Tbsp of Coleman fuel into the carb and it started right up and then ran for the next 2 hours flawlessly on the fuel in the tank. 

Questions: First, why didn't the ether work? In previous years ether has always been a staple for getting this engine running, especially since I don't normally use a heat lamp on the carb. Second, higher octane is harder to ignite. OK, then I need a fuel that vaporizes easier in cold temperatures making it easier to ignite, or lower octane. The gas in the tank was 87 octane with 10% ethanol. So getting a little ridiculous, doesn't diesel fuel have an even lower octane rating than gas? Why not use that? OK, diesel doesn't have nearly the volatility of gas. So there must be more going on than just octane rating. 

On top of this confusion, one friend says to use premium gas and another one says emphatically not to use gas that has ethanol, which around here is getting hard to find. 

I wonder whether gas formulations have changed over the years due to the wide use of fuel injected engines now. Is the same degree of volatility needed when the fuel no longer needs to be vaporized in a carb? I understand that refineries produce summer and winter gas, with the winter formulation being more volatile. Seems like that would favor an engine with a carb. But it's sure not working in this one any more.

Now I'm really confused.

MT


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## Basementgeek (Feb 7, 2005)

First starting fluid dissipates very quickly. I always shoot straight into the carb, after I open the choke. Open choke, ½ second squirt, Close the choke, start right away. I never use it in spark plug hole. 

Don't ever think about diesel fuel, it will not run.

Regular gas with no more than 10% ethanol should be fine. More than 10% can cause rubber parts failure.

BG


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## SABL (Jul 4, 2008)

Coleman gas?? As in camping fuel?? Has an octane of 50-55.....that's real low. Will the engine fire with the regular 87 octane poured in the carb??

Good luck finding gas without ethanol but I don't think that's the problem. The engine should run fine at 10%.


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## Midnite Tweeker (Jan 30, 2014)

I would never use diesel. That was a rhetorical thing. 

Yeah, Coleman the camping fuel stuff. The same stuff that says not for use in internal combusion engines on the can. I had tried both regular ethanol gas splashed in the carb, and when that didn't work, splashed in the sparkplug hole. And when that didn't work, then ether shot into the carb and when that didn't work then into the sparkplug hole. These are things that I've done in the past (with the exception of using Coleman fuel, that was new) that have have always gotten the job done.

It gets even more curious. Yesterday things had drifted in and it was time to fire up the blower again. Still had the trickle charger on it and the heat lamp on the carb, but no block heater. Instead of reaching for the Coleman fuel right away, I decided to revert to my "normal" method, that is, a one-second shot of ether on the air filter and then crank. Bang. Started right up, much to my pleasant surprise. Ran fine for another couple hours.

But now this comes full circle back to where I was after replacing the magneto coil (the original cause of no spark.) I tried every combination of gas and ether in every possible location and nothing worked. Though now that I think, I probably had the new plug installed at that time (and don't now.) And the air filter was off so the ether went straight into the carb body instead of onto the filter. And it was a different brand of ether.

Of the 3 variables---new/old plug, filter/no filter, different brand of ether---which most likely caused the starting problem? They all seem unlikely to me.

If I remember, I can switch back to the new plug next time & see if it makes a difference. 

MT


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## Basementgeek (Feb 7, 2005)

I would have to try another new plug first. Make sure it is properly gapped before installing. 

BG


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## Midnite Tweeker (Jan 30, 2014)

Ran it again yesterday. Instead of switching back to try the new plug, I left the old one in place. The change to the procedure was that I opted to try starting without using any ether. Heat lamp was still on the carb, but no trickle charger and no block heater. It started right off. 

So apparently ether is not what was making the difference. I'll try the "new" plug next time. 

Can having the air filter off make it hard to start? When this first began and I couldn't get it started, after first shooting ether on the air filter the next thing I did was remove the filter so I could shoot directly into the carb. The filter stayed off after that, even after I identified the root cause of not starting as being a bad coil and replaced it. With the filter off, I couldn't even get a pop until I tried Coleman fuel. 

Now with the filter back on, normal gas seems to be working again. 

Something caused a major hiccup bringing this back to life after the coil change, but I'm darned if I can figure out what. It just doesn't make sense.

MT


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## Basementgeek (Feb 7, 2005)

Yes, the air cleaner can make a difference. Just an FYI, snow blowers generally don't have air cleaners.

BG


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## k2skier (Sep 30, 2008)

Without an actual spark tester or a leakdown tester (a comp checker wont work) you will go mad before you get this engine running. I have worked on a lot of these and if you bought it new and it's never been worked on it WILL need a valve job, guaranteed. The valves need adjusting, stem grinding, and 34 years is way past time.


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