I think i would very carefully clean the block with something, and any other part that is oily. And,I think i would order an ignition set for it, too. 10 years of hard hot summer work surely will make something "give up" Just about the time you really need it.
Other than the usual oil changes and what you have been doing, i'd think you must have bought a good engine.
I'm curious as to what it looks like. Can you post any pictures here?

Rusty, no camera here right now. It's a single cylinder 13 HP engine. It's pretty low tech and I think thats why it's done well so long. Intermotor is part of Lombardini which was purchased by Kohler. Tom

that thing a two storke? I don't fix nothing that not broke especially if it runs good. Keep the air filter clean, the oil level checked or changed if it has a crank case, clean the carb by using an additive or carb cleaner (Tank clean out would probably not be a bad Idea if you having done it in 10 years along with a fuel hose inspection for dry-rot if it has rubber hoses? would be normal routine pre-ventive maintenance based on hours or months of use not something bi-decade.

Found this video of what looks like an older Goldoni 14 walking tractor setup with a powered trailer(!). There's a lot of neat stuff out there that we don't see in the USA. Apparently there's a lot of attachments made for these.

Here is a link that might be useful: Goldoni walking tractor video

..and check out this video link of walk-behinds. They're huge!

Here is a link that might be useful: Huge walk-behinds

rc- it's a four stroke. I've done all you mentioned including having chaged the fuel lines a few times over the decade. It just keeps running well with oil changes and air filter (oil bath) maintenance. It's one bow to modern engines is an electronic ignition. While parts are available I'm plannig on purchasing a new starter motor, fuel pump and ignition over the next year.

larsol- the Goldoni's haven't had an equal in the US since the Gravley went out of production. The video you posted shows some of its features. It has two PTO's so one can drive the rear end of a cart and operate a spray pump. There are brush hog, sickle bar cutter and hay bailer implements. I have a furrower which itself is over 100# and a cultivator (tiller). With the cultivator the unit weighs in around 600# which gives it lots of traction. It also has a slip differential and lock out. But of course the engine is what makes it all run. The new units have Intermotor diesels and if this engine ever went I may go that route with a replacement. But my goal is to have this engine run well as long as I do.
Tom

All I can say is " WOW "!. I try to find out some history on the routine maint. Sounds like you've been doing it. I would think the present engine would run a very long time still. I sure you can find a gas replacement if it ever comes to that it would be about 10 times cheaper than converting to diesels. I picked up a 17.5 single kohler on ebay for 300 bucks with tags hanging off it. So I would shop around if present engine ever fails which I dough will be for awhile.

shouldn't hurt it all try to clean it up using degreaser and low GPH spray from a pressure washer and fan nozzle pattern. I do it all the time. Course you want to keep your electronics covered up.

How about a brand new single cyl., air-cooled 13HP chinese mfr. replacement diesel for only $695 from an on-line TN outfit. Has both electric and pull-recoil start and is supposed to be a Yanmar clone, even able to use Yanmar parts. Has a free parts replacement warranty for one year, and a 30 day full purchase price return policy. Can't hardly beat the price ...or the torque output. Or how about a monster 22-HP twin for $1295.00. Some guy on another one of the tractor forums is starting to use these as replacements in the older large frame Bolens tractors. Very interesting....

Here is a link that might be useful: Chinese diesel repower

These are neat engines. I have a BCS 735 with a 10HP Acme Motori and the easiest way to clean them up is with Super Clean. Cover items like the carb and coil and you're good to go.

Bushleague, I think the Acme replaced the Goldoni on some units because the Intermotor didn't meet emission standards. Have heard great reports on the Acme. I'm fortunate to have a shop manual for the Intermotor and one for the Acme series FE 82W, AL 480W/550W and BT 88W/94W. It's in Italian but glad I have it because the Acme would fit the Goldoni. Thanks to everyone. Sounds like it's time to get some Super Clean and new fuel lines. Thanks - Tom

Wow larso, what a neat vid. Balade Motoculteurs (French) Translates (with some persuasion) as "A drive of pedestrian controlled tractors"
Acme?? I hope this ain't the same "Acme" Wile E Coyote was always ordering from.

Thanks for the translation mownie.

The engine cleaning should include taking off the shrouds around the engine and making sure no debris is blocking the cooling fins.
You may be surprised how much grass may be stuck in there.

I bought mine from Earth Power, I sure miss them--or at least their main guy Bob Daniel. I've set up a Yahoo group in the hope that those of us with these amazing machines can compare notes and help each other. Looks like I'm not allowed to post group links, so just search for a Goldoni walk behind tractor.

Regards... Andy Valencia