Old 5HP Rototiller fouling plugs.

[Hammermechanicman]

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.

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.

 

[StarTech]

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

 

[Hammermechanicman]

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

 

[cprodave]

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

 

[cprodave]

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...

 

[Hammermechanicman]

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]

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.

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.

 

[RevB]

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.

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

 

[StarTech]

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.

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

 

[cprodave]

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...