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

[freedomlives]

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]

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

 

[freedomlives]

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]

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]

:-/
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]

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]

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]

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]

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]

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...

 

[leonz]

Are you sure you just don't need a new coil?? The coils and flywheel magnets are both supposed to be T.D.C.

if the coils are anything like the B+S coils the top flap of the box is the universal gauge to set the coils distance from the flywheel.


If that "supposed rock" did break the shear pin its entirely possible that the key is sheared or partially sheared and runs when the magnets meet to start then to have it die a few seconds later.

You should be able to find a supplier of small engine tools close to you or in Italy as the flywheel spanners for small engines are pretty much universal.

 

[freedomlives]

No, it isn't like B&S (granted, that I've never dealt with the ignition on those, only at most cleaning the carburettors). For setting the distance from the coil to the flywheel, the repair manual (in Italian) says to use a piece of card stock 0.5-0.6mm thick.

I'll just try to come up with some way of holding the flywheel-- maybe ratchet cargo straps could give a good enough grip. Till I figure out how you call "flywheel wrench" in Slovak... The strap wrenches I've found on the market here seem aimed at oil cans. Only Fabory (a Grainger company) has a big strap wrench, but 70€ for a tool that I might possibly just use once is a bit high...

Well, once I get the motor going right, then there is the question why it doesn't go in to the low forward speeds. With the speed reducer on, which also reverses wheel direction, I can use hi and lo reverse speeds as forward and get the rotary plowing done and potatos planted anyway.

 

[milkman]

To hold the flywheel try using a length of small diameter rope inserted through the spark plug hole, I know that works well on a two stroke engine. Just make sure the piston is coming up on compression stroke to prevent bending an open valve if overhead valve engine.

 

[PILOON]

To hold the flywheel try using a length of small diameter rope inserted through the spark plug hole, I know that works well on a two stroke engine. Just make sure the piston is coming up on compression stroke to prevent bending an open valve if overhead valve engine.

My trick for retaining round objects is to use an old V belt and pair of vicegrips , that way there is no slippage.

 

[freedomlives]

The belt and visegrips worked! Especially when I started turning the nut clockwise instead of counter-clockwise... :ashamed:
Now pulling the flywheel is another thing. It has two holes for 10mm screws to lock in the special tool I don't have. I put some hex-head screws in them, and tried using an ordinary pulley-puller with the legs gripping under the screw heads, but not much luck. Seems I need to fashion a puller like what they have.

 

[freedomlives]

Or, even better, is just order a puller... 12€...

I don't have thick enough pieces of metal to rig something up-- tried with some square tubing, and it just bent! Now more waiting...

 

[buickanddeere]

It's fine, leave it alone and run it as is. Incandescent exhaust gasses are not a crisis.

 

[freedomlives]

I'm pretty convinced its not fine, since after I adjusted valve lash to manufacturer settings (e.g. so that there is even lash-- there was no space between the rocker arms and valves), then the engine wouldn't run. And now, as I took off the valve cover to double check the valve lash, I notice rotating the engine that the intake valve gets a bit opened for a moment during the compression or power stroke. I'm pretty sure its not supposed to be doing that!

Though I also don't understand how that could be happening. I guess a cam lobe could get deformed and stick out a bit?

 

[freedomlives]

The flywheel finally came off. And indeed there was no shearing of the key (which is a 4mm thick by 5mm tall woodruff key in case anyone wonders before they take their flywheel off. Or maybe 6.5mm tall is the correct size. The dimensions on the key are actually odd).
So still I'm vexed about that valve, as seen above. I should have tested compression before pulling the flywheel, but like is seen in the video, it certainly must be low as the valve opens a bit during the intake cycle.

 

[freedomlives]

So, I don't know that I can call it fixed, because of that valve opening, but when I set the rocker arm clearances correctly and then figured out that the fuel valve for some reason closes when it is turned 90° and is only open at around 70°, then it started and it runs. And that's good enough for now, so I can get the garden beds done.
Spare parts don't seem to be readily available for this engine, so I'm just keeping my eye out for when someone here will sell a compatible Lombardini diesel engine, as spare parts for those are available, and the price of fuel in the EU (thanks to tax policy) is such that a diesel engine is worthwhile a lot sooner.