Old 5HP Rototiller fouling plugs.

[cprodave]

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.

 

[ILENGINE]

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.

 

[cprodave]

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

 

[Rivets]

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

 

[cprodave]

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

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?

 

[Tiger Small Engine]

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?

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.

 

[Forest#2]

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.

 

[cprodave]

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.

 

[hlw49]

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

 

[Forest#2]

look here for IPL

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/briggs-stratton-engine/100000-19z999-series/130200-to-130299/130202-1915-01

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.