Briggs& Stratton engine will not turn over

[JimP2014]

Dumb question here, but is it possible the ignition coil is on upside down? There is an up/down or in/out on the coil. This will screw up timing. It may not even run, depending on model.... OEM Coils are usually marked. Another thing I noticed on the parts warehouse link you included is there are three different coils for this engine. You would need to know the date code of your engine to be sure you have the correct coil if you replaced it.

I have to put the original coil back on and this is a good point you make. Honestly, I don't think it'll make any difference but I absolutely will put the old coil back on.

 

[JimP2014]

You are running that engine too long without the fan and shroud.
From cold start up the engine should not be run over 15 seconds.

You need to stop playing with it until you get a cooling fan on it. If you need to run it longer than 15 seconds install the shroud. You say you don't want to spend any money on a plastic fan.
If you want to keep on playing with it at least go to a small engine salvage and buy a junk engine for parts.

That piston if not already happened is going to expand as it gets hot and swell into the cylinder wall and severe scoreing will result.

I'm surprised that it has not

You are running that engine too long without the fan and shroud.
From cold start up the engine should not be run over 15 seconds.

You need to stop playing with it until you get a cooling fan on it. If you need to run it longer than 15 seconds install the shroud. You say you don't want to spend any money on a plastic fan.
If you want to keep on playing with it at least go to a small engine salvage and buy a junk engine for parts.

That piston if not already happened is going to expand as it gets hot and swell into the cylinder wall and severe scoreing will result.

I'm surprised that it has not shelled

You are running that engine too long without the fan and shroud.
From cold start up the engine should not be run over 15 seconds.

You need to stop playing with it until you get a cooling fan on it. If you need to run it longer than 15 seconds install the shroud. You say you don't want to spend any money on a plastic fan.
If you want to keep on playing with it at least go to a small engine salvage and buy a junk engine for parts.

That piston if not already happened is going to expand as it gets hot and swell into the cylinder wall and severe scoreing will result.

I'm surprised that it has not shelled out already.

Forest, thanks for the heads up on this. Even with everything put back in a partially broken flywheel fan which recently broke and I have no clue why. But the point is what you're saying makes a lot of sense about the fan and go to a place that has old engines before anything else. I do appreciate this post. And just for the record, with everything put back, it is hunting and surging and that might be a carburetor I'm hoping but the temperature is still 770° f

Jim

 

[JimP2014]

Forest, thanks for the heads up on this. Even with everything put back in a partially broken flywheel fan which recently broke and I have no clue why. But the point is what you're saying makes a lot of sense about the fan and go to a place that has old engines before anything else. I do appreciate this post. And just for the record, with everything put back, it is hunting and surging and that might be a carburetor I'm hoping but the temperature is still 770° f

Jim

Forest, I did take a look at that flywheel fan. I was looking for some numbers or letters and there is nothing except the Briggs& Stratton logo put. The one I have has two dimples on the bottom and I can buy like three parts and be sure I got the correct plastic fan but I am trying to figure out that part isolated what the number is for it because it's like half the cost and that's all I really need.

 

[birddog2790]

https://www.partswarehouse.com/31P677-3373-G2-Briggs-and-Stratton-Engine-s/235041.htm

Thank you very much for your assessment. That makes a lot of sense, especially the part about. Well, if the spark is at the spark plug then you can just rest assure it has nothing to do with all that safety stuff that is key. But beyond that, what you mentioned about compression and the other stuff is what I suppose I need to look at. I can only say that maybe 10 days ago there was an awful banging going on every time there was a rotation of the flywheel and I wonder if eventually that broke something don't know. But again I appreciate your help.


Jim

My guess, for what it's worth, TIMING!
Lee

 

[DABS]

I just read in some other form. This sounds kind of like what's going on with my riding mower.

https://www.doityourself.com/forum/outdoor-gasoline-electric-powered-equipment-small-engines/352247-briggs-stratton-wont-start-but-has-spark.html

Except he finds out there's a bent push rod or a broken push rod and then everything's fine. I have no broken push rod and the push rods are perfect.

So I might just take off the flywheel pretend it's broken and put a new flywheel key in and try again for timing issue


Jim

My guess, for what it's worth, TIMING!
Lee

I’m guessing governor gear and bent crank

 

[SamB]

Forest, I did take a look at that flywheel fan. I was looking for some numbers or letters and there is nothing except the Briggs& Stratton logo put. The one I have has two dimples on the bottom and I can buy like three parts and be sure I got the correct plastic fan but I am trying to figure out that part isolated what the number is for it because it's like half the cost and that's all I really need.

There is a lot of advice flying around here, so I'll only post about your fan. The dimples are a cost cutting measure and those dimples go into the flywheel bolt holes where a bolted on fan's bolts would go. Dimpled fans are held on by the flywheel nut On some engines, the fan screen is also under the flywheel nut. On all 4 of my single cylinder Briggs engines, the fan blades are connected on top with a reinforcing ring that looks like this would prevent breaking.
This is a link to a seller on eBay that I have dealt with and had good outcomes at all the sales. This is a bolt-on fan that does not have to remove the flywheel to put on. just two bolts in the puller holes in the flywheel.

Briggs and Stratton OHV Engine Model 31F707 Fan Free Shipping | eBay

Briggs and Stratton OHV Engine Model 31F707 Fan Free Shipping. Condition is Used. Shipped with USPS Priority Mail.

www.ebay.com

 

[JimP2014]

I just went back outside at 3:15 p.m. I am keeping in mind running this even with everything back in place for under say 20 seconds. I can say it started right up. It sounds like the engine's strong and a lot of hunting and surging. So in a couple seconds that I had, I started messing around with the fuel air mixer screw. Apparently from what I read hunting and surging as a result of the engine running lean. So I've been trying to adjust it by turning the screw clockwise which makes the fuel there mixture screw close up the tiny hole which means less air more fuel but I then shut it off. The spark plug hole is stripped but I am trying to figure out if most of the engine is good which means get another cylinder head. Get another flywheel fan. Get another ignition coil brand new Briggs& Stratton type but if right now the only thing I can see for sure is hunting and surging with a strong engine. Would most folks keep going or get a new riding mower?

Thanks,
Jim

 

[JimP2014]

There is a lot of advice flying around here,so I'll only post about your fan. The dimples are a cost cutting measure and those dimples go into the flywheel bolt holes where a bolted on fan's bolts would go. Dimpled fans are held on by the flywheel nit.

Right on that. The part I'm looking at off the top of my head is Briggs& Stratton 796201. I think that's what it is

I just went back outside at 3:15 p.m. I am keeping in mind running this even with everything back in place for under say 20 seconds. I can say it started right up. It sounds like the engine's strong and a lot of hunting and surging. So in a couple seconds that I had, I started messing around with the fuel air mixer screw. Apparently from what I read hunting and surging as a result of the engine running lean. So I've been trying to adjust it by turning the screw clockwise which makes the fuel there mixture screw close up the tiny hole which means less air more fuel but I then shut it off. The spark plug hole is stripped but I am trying to figure out if most of the engine is good which means get another cylinder head. Get another flywheel fan. Get another ignition coil brand new Briggs& Stratton type but if right now the only thing I can see for sure is hunting and surging with a strong engine. Would most folks keep going or get a new riding mower?

Thanks,
Jim

I lost the post but someone was telling me about the flywheel fan and I could say the part that I need is Briggs& Stratton 796201 and that's everything but I only need the plastic piece but if I have to purchase the 796201 I will. I just have to know if it's the right thing to do like this engine is salvageable and I'm very close and like I just said it starts right up. Seems like it has power. It's just wild hunting and surging and maybe just a fuel air mixture screw but it does need a cylinder head to fix the spark plug problem

Jim

 

[JimP2014]

This is from 5:15 p.m. July 6th so the engine starts. Right up and at least I guess I only contend with one variable now hunting and surging. It sounds like the carburetor so I put the fuel mixer screw in all the way and then I backed it out about one turn and every 30 minutes or so I back it out about another quarter turn. So right now it's that 1.5 turns from completely tight

This is not typical for me to spend this much time with a fuel, air mixer, screw or probably anyone else. But the link I provided is basically how it's running and only for about 15 or 20 seconds and then I shut it down. The other issue is couple weeks ago and I mentioned that I was cutting the lawn and it shut down well. The other thing that happened at the same time was the weld for the exhaust pipe to the muffler came undone. So right now it's just the exhaust pipe that's in place. And again I'm trying to figure out is this salvageable am I very close to solving the problem with this engine or is there something seriously wrong with it that this engine is garbage? I mean with just hunting and surging you might conclude you're only 5 minutes away from fixing this thing. I'm just wondering if the whole thing is destroyed somehow and the only real symptom is hunting and surging?

Thanks,
Jim

 

[gregjo1948]

In the last two weeks I've done many things, but in the meantime the current problem is this definitely getting spark to the spark plug after spraying carburetor cleaner into the intake while turning the key. The only thing that happens is backfire through the carburetor or popping the engine refuses to start. The only thing I can think of is the spark plug is definitely working, so I'm wondering if there's some kill switch that allows for the flywheel to rotate where it seems everything will start and engage flywheel and the engine. But at the very last second a kill switch shuts off everything and prevents it from starting. So in other words, I'm looking at carburetor problem but maybe I should be looking for some kill switch that's shorting out everything. It's as if all systems are go but at the last second this kill switch is preventing the engine from starting I wonder if anyone is familiar with this situation before. Also, the fuel solenoid definitely clicks when you turn the key but the carburetor cleaner going into the intake. Even if there's a kill switch situation on going, I would think the engine would start up for a couple seconds. I don't think a kill switch, even if active could prevent the engine from starting for at least a second or two, but that's what it seems like is happening.


Jim

Stop spraying carb cleaner into it. It doesn't burn well. Try spraying starting fluid. I doubt that it has a kill switch. There is probably an ignition switch somewhere on it. It probably is the switch you're turning to crank it over. To test the compression, remove the sparkplug, stick a finger or thumb over the sparkplug hole and crank the engine over. If it has compression, it will push your finger/thumb away from the hole.