Is it blow-by coming from your exhaust?

Therein is the mystery! I don't know. What can be done if it is?

It appears to be dripping down.

1. Is it 2cycle or 4cycle? If it’s 2 cycle, pull the muffler and spark arrestor and inspecting the piston and cyl for damage as deep scores.

2.4Cyl or both look for any restrictions related to cooling that might be causing extra heat and oil break down.

3. Ck the compression and ck for any loose case bolt.

4. A good cleaning and observing w/o using might point toward the problem

5. I am thinking about basics since I have not own or seen the unit.

Good Luck!

It's a 4 cycle, and the oil is dripping down. I'll do as suggested. Thanks for your comments.

I did some searching knowing there had to be some missed tips. I only saw the many good words about the good running engine and bad transmission. I find this strange that the leak has not been discussed or d/n spot it.

With this quality and price, I wonder if a percentage leakage test would be in order vs a teardown. Adding controlled pressure into the spark plug hole (with the crank locked from turning) and observations could show possibly problems. IMO That would be the same as cleaning it good and let it run w/o using it as you look for the leak.

Other than that, if the valve cover is in the high area of the leak, I would give it a good look as well as case joints. A good exploded engine parts diagram could be helpful vs seeing one I thought was.

Last if you feel it’s trans oil, there might be a harmless automotive dye you can add to it and use a black-light to prove that it is the trans seal. Leaking down might rule that out.

This is interesting!

As I mentioned, I can check the crankcase oil level and it has not gone down. Pull the tranny fill plugs and I find the lithium grease level is a varying percentage gone depending on how long I have used the tiller.

1. Is the trans in a position to produce oil that high or is the bouncing placing it high?

2. The trans seems to be the best suspect. Is it easy to seal onto the unit and Etc seals?

3. Do you know of a link that shows Trans gasket and surfaces to seal and Etc seals?

4. I hope my interest is not irritating you vs trying to help that might help a Local.

5. Small engines have been part of my life since the mid 60s and I have slowed LOL!!!

6. I’ll move on and hopefully see a good follow-up on your find and fix.

Take Care!

Your interest is NOT irritating at all. Two heads are better than one. Maybe you can help me see something.

The weird part is the diagrams showed no gasket between the tranny and the engine, and I originally installed it with no gasket or sealant. When I pulled it apart this spring I slathered high temp RTV sealant on both surfaces and allowed it to set for several days before trying it out. Strange that there isn't any surface that looked like it was designed to have a gasket.

Perhaps the bouncing that these mini tillers do is what splashes the oil up and out. Odd too is that the clutch does not become oil soaked as I thought it might.

Thanks for your thoughts and comments. Looks like you have a long history with small engines.

Please share a link to your diagram. Have you contacted Honda, a Rep or Dealer/Shop on the matter?

here is a link that shows the transmission: http://www.partstree.com/parts/honda/tillers-cultivators/fg100-a-honda-tiller-made-in-usa-sn-fzcv-6000001-to-fzcv-9999999/transmission/

And no, I have never attempted to contact a Honda repair shop—none in our area—nor a rep. Since I bought this in '01 or '02, I figure that's obsolete and forgotten in their playbook.

Followup: Once again I removed the transmission looking for the leak. I could find nothing, but when I reattached to the engine I torqued the hell out of the bolts. No leak since!