Intermotor/Lombardini 12HP gasoline motor flame out the exhaust?

freedomlives · Mar 15, 2017

I just got another Goldoni Special from Italy, this one with reversible handle-bars and a gasoline engine. Just now at dusk I've unloaded it from my van and fired it up, and I noticed quite often a blue flame, about 6 inches long, poking out of the exhaust. When I went to stop the engine, I also noticed that a circle about 1.5" diameter on the body of the muffler was red hot.
Is that normal? Is it running too rich of a fuel mixture if a flame is coming out? Or should I just be glad that any excess hydrocarbons are getting burned off and not causing pollution?

It sure is easier on my ears than the diesel motor!

Maine Hills · Mar 16, 2017

Possibly too rich a mixture and/or retarded ignition timing (spark too late).

freedomlives · Mar 16, 2017

At least Kohler group-- owners of Intermotor, Lombardini, etc. has all of the service manuals for their motors online. Unfortunately, the service manual for the Intermotor LA 490 is only in Italian!

PILOON · Mar 16, 2017

Blue flame suggests hot which suggests lean mixture, that or timing is off.
BTW that is a recipe for burning valves. (you also noticed red hot muffler)

freedomlives · Mar 17, 2017

:-/
Previous owner mainly used it for the snow blower. Would carburetors get adjusted differently for cold weather use?
It had mounted on it speed reducers, which also reverse the direction of the wheels and shift the center of gravity towards the engine, which would be advantageous for front facing attachments. I removed them yesterday, adjusted the wheel spacing to get it ready for using the rotary plow, and then discovered it doesn't want to go in to low forward speed (which, with those reducers on, was low reverse speed, which I didn't see demonstrated in Italy). So another thing to fix. :-/
But at least once I get the carb or timing sorted out, I can put the reducers back on and then I'll have the right forward speed with the reverse gears for rotary plowing. I don't look forward to opening up the transmission!

mcfarmall · Mar 17, 2017

Had this same exact problem with a Tecumseh engine on my snowblower. I was absolutely convinced it was a carburetor problem and tried several times to adjust the main jet to correct the problem. More or less by accident I discovered that the flywheel key was partially sheared causing the ignition timing to be off. A quick glance at the key and it looked ok but a close examination revealed that it was just ever so slightly sheared but it was enough to cause a problem. Put a new key on the engine and she runs great, no more flamethrower.

buickanddeere · Mar 17, 2017

It ain't flame, just looks like flame . What you are looking at is exhaust gasses hot enough to glow , not all that different than an incandescent lamp filament or a Coleman lantern mantle.

CodeMonkey · Apr 1, 2017

I would think that is rich. I have noticed around dusk that my Grillo 110 does spit out sparks under load, which is disconcerting as most of the time I use it is with a flail mower during fire season.

freedomlives · Apr 3, 2017

I started taking it apart, but then I got stuck with how to hold the flywheel to undo its nut to check the key. I bought it from a garden equipment service shop in Italy, and the guy selling it told me the previous owner just had used it with the snowblower attachment. That and the fact that there is a problem (which of course I only noticed after I bought it) getting it in to one gear leads me to suppose that the previous owner hit a rock with it. So that's why I started with "gusto" to dig in to check the flywheel key!
I hunted around today and read about the trick of putting rope in the cylinder through the spark plug hole to hold the flywheel. But now I also notice the spark plug has quite a lot of black carbon fouling. Maybe I should have checked that first. But I'm going to go ahead and pull the flywheel and check for that key, now that I'm almost there, and then I can try to google translate the instructions about the carburetor adjustment.

freedomlives · Apr 3, 2017

I'll have to fashion some sort of flywheel holder. It is cast iron, but I still don't feel comfortable jamming a screwdriver in the fins.
In the meanwhile, I decided to check the valve rocker arm clearances. Well, there wasn't any clearance, so would mean that the valves possible weren't even closing all the way. Now that I've set that to 0.2mm as per the instruction manual, the best I can get is that it starts and runs for about 5 seconds. It has a transistor type ignition circuit, and as I understand it, they ****** the timing to make start-up easier, and once its running the timing advances. So I wonder if this isn't a clear indication that that flywheel slipped. I wish I had a picture of where the magnet is supposed to be in relation to the ignition coil at TDC. But I guess I just need to get a huge strap wrench or fashion a holder for the flywheel and pull it off...