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I recently bought an old Southern States brand rototiller that has a 5HP B&S that is hard to start and fouls plugs. Model is 130202, Type 1915 01, Code 84120606. Looking inside the spark plug hole I can see quite a buildup of carbon. Compression is only 60 psi ( I work on a lot of old small OMC outboards where less tha 80-90 psi is generally considered to be low/problematic. Except for really old outboards that had low compression by-design).
Am I wasting my time going through the usual fixes for Fouling Plugs (lean-down the fuel/air mix, reduce gas flow, increase air flow, new rings to increase Compression, etc?)?
Thanks for any guidance.

60 psi on those old Briggs flathead engines was not unusual even out of the box new. They run a modified camshaft lobe that holds one of the valves open longer than it should which acts like a full time compression release. Something that would be a good idea on an engine that old is remove the had and clean up the carbon but also relap in the valve and reset the valve clearances. The old briggs would wear the valve faces to the point that they will float the valves. If you remove the head and open on of the other valves then put your thumb on top of the closed valve and see if it turns. and then repeat for the other valve. I suspect the intake valve will turn indicating it isn't sealing.

ILENGINE, thanks for your prompt input. Good to know that 60psi is not unusual for these older engines and that "all is not lost" . If I can find a Head Gasket for this then I will probably clean up the carbon/relap/reset. (this assumes old gasket is not reuseable). Meanwhile I will diagnose if engine is not getting enough Air (the Air Filter is really old--might be Original!) and if I can lean-down the Fuel. It seems like both of these actions can be done at little to no cost.
More detail on the Hard To Start Failure Symptom: when attempting a Cold Start --if I put on Full Choke the fuel gushes out of (I believe specifically) the Air Filter. This would seem to indicate a very healthy (almost too much--if there is such a thing) amount of Crankcase Vacuum. But there must be something else that causes this--any ideas? So meanwhile it seems to Cold Start OK using No Choke and a shot of Starting Fluid. I would like to get this situation resolved.
Thanks again for your guidance.
Dave

Stupid question, but what is the plug number you are using? Could just be that the plug is too cold.

Rivets said:

Stupid question, but what is the plug number you are using? Could just be that the plug is too cold.

Click to expand...

Rivets, Thanks for the idea. That is actually a pretty good question, not stupid at all. I haven't researched what the factory-recommended spark plug is. I know only that when I purchased this old rototiller it had a very rusted (i.e. seized-in!) Champion CJ8 spark plug so I replaced it with a new CJ8.
It is possible that a hotter plug would help so I will try that. However there is something else going on that causes the engine to "puke fuel" out of the Air Filter/Carburetor area. It doesn't make sense to leave the excessive Fuel condition unaddressed.
Right?

cprodave said:

Rivets, Thanks for the idea. That is actually a pretty good question, not stupid at all. I haven't researched what the factory-recommended spark plug is. I know only that when I purchased this old rototiller it had a very rusted (i.e. seized-in!) Champion CJ8 spark plug so I replaced it with a new CJ8.
It is possible that a hotter plug would help so I will try that. However there is something else going on that causes the engine to "puke fuel" out of the Air Filter/Carburetor area. It doesn't make sense to leave the excessive Fuel condition unaddressed.
Right?

Click to expand...

Puking fuel is probably a valve related issue on this 5 hp flathead engine. Pull the breather cover and check your valve lash. Look for spec online and how to check valve clearance if any questions. You have to grind the valve stems down if adjusting is needed.

Just a hint to make the valve lash adjustment little more user friendly labor wise on the old valve in head L-Head engines..
If you find that the intake valve lash is below specs (valve lash too close) and you remove the valve to remove/grind some off the valve stem off, do not use a power grinder. I first gauge the existing clearance valve lash with the spring installed, remove the valve and re-install it without the spring pushing down hard on the valve and check again and compare the two measurements, then hand file the amount needed and constantly re-checking without the spring. This eliminates the re-checking by constantly installing and removing the spring to test the lash.
Just color the end of the valve stem with with a marks a lot pen then hand file until to color goes away. When the marks a lot color goes away it will be about .002-,003 removed. The end of those stems file easily. Using a power grinder can easily result in too much removed from the stem and the compression release won't work and a new valve then needed.

Update: yesterday I ran a couple Start/Stop cycles to see if I could determine exactly where the excess Fuel is coming from. As I went to do another Start cycle the Rope Starter does not move! Engine is acting like it seized-up. This is very surprising because each cycle I ran only a minute or so, and engine made no unusual noises (I know what a small outboard sounds like when it is about to throw a Rod--been there, done that!).
Is there any chance the pseudo-CompressionRelease on this has activated? This seems unlikely as I removed the Spark Plug and Rope Starter still does not move. If not, what should I inspect for as I remove the Cylinder Head, Valves, etc? Is it possible that a valve has stuck or similar, and I have a (as yet) non-destructive Interference Fit?
One last question: anybody know where I can get a good Exploded View Diagram on this engine?

Thanks for any help.

Valve lash is .005 to .007 on the intake and .009 to .011 on the exhaust. Cylinder head torque is 140 inch lbs.

look here for IPL

Appears maybe the oil got thinned out from the puking fuel and it lost a rod.
Remove the recoil and See if you can turn the engine backwards.
Parts even if available is costly for new stuff. Might be time for the crying towel.

Might be time to think about a $100 Predator engine if the gearbox of the tiller is any good.

cprodave said:

Update: yesterday I ran a couple Start/Stop cycles to see if I could determine exactly where the excess Fuel is coming from. As I went to do another Start cycle the Rope Starter does not move! Engine is acting like it seized-up. This is very surprising because each cycle I ran only a minute or so, and engine made no unusual noises (I know what a small outboard sounds like when it is about to throw a Rod--been there, done that!).
Is there any chance the pseudo-CompressionRelease on this has activated? This seems unlikely as I removed the Spark Plug and Rope Starter still does not move. If not, what should I inspect for as I remove the Cylinder Head, Valves, etc? Is it possible that a valve has stuck or similar, and I have a (as yet) non-destructive Interference Fit?
One last question: anybody know where I can get a good Exploded View Diagram on this engine?

Thanks for any help.

Click to expand...

The compression release on this engine is simply a small bump on on the intake valve closing ramp. It will not stop the engine from turning.

But a carbon up valve stem will or seized bearing. Be it rod or otherwise.

Most likely either rod seized on crank or crank seized in case.

Thanks for the inputs. I will check for these situations. I hope the engine is not "toast".

I got the head off--bolts not frozen on as I feared. There is a lot of carbon (photo to follow) which MIGHT indicate a stuck valve. I can rotate the Flywheel just a bit which results in the Piston moving up and down about 1/64 to 1/32inch. So I suspect that the Piston is not seized to the Cylinder Wall. Not sure what this slight movement ability means re: possible seizing of Rod to Crankshaft or seizing of Crankshslight to Crankcase.
Is it possible to unseize a Stuck Valve (if one is in fact Stuck) without disassembling the the Crankcase sides? (assuming the Cylinder and Center portion of Crankcase are a single piece p/n 49495 per Parts Diagram). Any advice on that? I am thinking some Lucas foaming lubricant, Marvel Mystery Oil, etc...

It's not a stuck valve. If they stick it is always open. Pull side cover which is hopefully not seized on the crank. Pull the cam out and see if you can turn the crank.

cprodave said:

I got the head off--bolts not frozen on as I feared. There is a lot of carbon (photo to follow) which MIGHT indicate a stuck valve. I can rotate the Flywheel just a bit which results in the Piston moving up and down about 1/64 to 1/32inch. So I suspect that the Piston is not seized to the Cylinder Wall. Not sure what this slight movement ability means re: possible seizing of Rod to Crankshaft or seizing of Crankshslight to Crankcase.
Is it possible to unseize a Stuck Valve (if one is in fact Stuck) without disassembling the the Crankcase sides? (assuming the Cylinder and Center portion of Crankcase are a single piece p/n 49495 per Parts Diagram). Any advice on that? I am thinking some Lucas foaming lubricant, Marvel Mystery Oil, etc...

Click to expand...

Hammermechanicman said:

It's not a stuck valve. If they stick it is always open. Pull side cover which is hopefully not seized on the crank. Pull the cam out and see if you can turn the crank.

Click to expand...

OK, will do. If I can't get to it tomorrow then it will be at least a couple days until I get this done and advise back. Thanks.

cprodave said:

I recently bought an old Southern States brand rototiller that has a 5HP B&S that is hard to start and fouls plugs. Model is 130202, Type 1915 01, Code 84120606. Looking inside the spark plug hole I can see quite a buildup of carbon. Compression is only 60 psi ( I work on a lot of old small OMC outboards where less tha 80-90 psi is generally considered to be low/problematic. Except for really old outboards that had low compression by-design).
Am I wasting my time going through the usual fixes for Fouling Plugs (lean-down the fuel/air mix, reduce gas flow, increase air flow, new rings to increase Compression, etc?)?
Thanks for any guidance.

Click to expand...

Is your carbon wet or dry....difference between oil and excess fuel.

Hammermechanicman said:

It's not a stuck valve. If they stick it is always open. Pull side cover which is hopefully not seized on the crank. Pull the cam out and see if you can turn the crank.

Click to expand...

I have to disagree as I had a couple to stick less than half open.

As I recall the carbon seems to be dry. So is that oil (not fuel)? Going to be at least a week until I get back hands-on to this project...

Dry normally means rich mixture, not oil.

There is no "psuedo-compression" release. The exhaust valve cam is made to hold the exhaust valve slightly open to release some pressure as the piston comes up making the engine easier to crank. The valve closed just before combustion to provide full power. If the valve lash is too much the exhaust vale closes completely and the rope pull will be difficult. A starter motor will turn very hard and may not crank the engine. Many a starter motor has been replaced and the new motor may work for a time, but the problem comes back. Accurately adjusting the valves solves the hard crank problem. The new cam was designed to make cranking easier. Once the engine is running, the compression release isn't long enough to matter.

Dry black carbon on the spark plug is the result of a rich mixture. Excess oil will make the black carbon have a oily, wet appearance.

If we are talking about a 5hp 13xxxx series briggs engine the "easy spin" bump is on the intake and not the exhaust. If the engine is not burning oil the most common cause of carbon deposits on the plug is not running rich but rather not running the engine hard enough to get the spark plug into the self cleaning range. The later engines were fixed main jet and unless the air cleaner was clogged it is very hard to run the engine too rich. Unless the engine is run hard enough to get the plug electrode to at least 900 degrees F the plug will carbon foul.

I took the head off and observed some light scoring at one location in the cylinder wall. Soaking for a day or so with Marvel Mystery Oil I got the piston moving freely again. I reassembled and ran a few start/stop cycles. It froze up again. I drained to oil and am now ready to remove the side cover.
Any tips on removing the side cover without butchering the gasket? There appears to be two Alignment Dowel/pins..do I light hammer tap on these? Also why are there 2 Oil Fill locations on this engine? One fill location is practically inaccessible on the assembled Tiller...blocked by Carb and Drive Belt cover.. thanks for ongoing help.

Your last post shows you’re in way over your head. What are you looking for by removing the crankcase cover? Chances of removing the cover without damaging the gasket are next to zero. You also must clean the crankshaft, or you’ll ruin the seal. If you are not careful you‘ll have tappets on the ground and will need the check valve clearance when you try to reassemble. My recommendation, stop and find a good tech.

Good info:
AS Rivets says
AND you are whipping on a dead horse. Time to throw in the greasy towel on that one. It's a good thing to get the model, type and code from old or any engine FIRST (if it's not rusted so bad to be visible and sometimes a Bubba has installed another air cowling and the ID info does not even match the engine) and then look online to see if replacement parts are even available and if so the prices. Several of the old Briggs parts are NLA or if available will cost more than a NEW replacement engine.

Look at the $100 Predator engines from Harbor Freight or I quite often I find really good engines on Pressure washers that have a bad pump for around $25.