Rough Running Engine

[NelsAnderson]

Well, I think I made some progress this afternoon.

I wasn't sure how to remove the carb jets but I decided to remove the top of the carb again and have another look. The main jet appeared to just screw out and sure enough it did just that. Looking through it the opening looked like a thin slit, which didn't seem right. A blast of carb cleaner through it and a much larger round hole appeared.

Starting the engine I was now getting white smoke out the exhaust, which I take to mean with the larger jet opening it was now running too rich. I turned in the adjustment screw and was able to make the white smoke stop.

But it's still running rough. I tried the hand over the air intake to try and finish clearing things. This seemed to help, but only briefly (the RPMs would go up and some times the puffing from the exhaust would actually stop for a second or two).

So I'm guessing I need to continue clearing things. Looking at the diagram, the fuel flows past the main jet into the emulsioning tube and air correction jet. It's not clear, does that just unscrew too? If so, that will be easy to clean.

There's also the pump jet. I don't see how that comes out though, any ideas?

Are there any other jets or whatever that might also need to be removed and cleaned?

[kevkon]

White smoke = oil ( it might also be from the cleaner you used)
Try pulling the plug wires one at a time ( yes you want to do this with insulation) see if you don't notice any difference in the engine.
I still wouldn't rule out bad gas. Look for any presence of water or debris in your sediment bowl or filter.

[Nium]

White smoke

Does the white smoke continue after the engine is at operating temperature? If so you may have a blown head gasket.

1. When the engine is cool remove the radiator cap.
2. Place the Landy so the top of the radiator is above the head. Jack up the front and put it on stands or park on an incline.
3. Start the engine. With the radiator cap off or just set the cap in the top of the radiator and not screwed down so you can remove it before it's hot.
4. Check if there is a continual stream of bubbles coming to the top of the radiator once it is at operating temperature (the thermostat is open and the upper radiator hose is hot). If there a continual stream of bubbles you've probably got a blown head gasket.

If you only get white smoke for a little bit after starting the engine then it's probably not coolant leaking past a blown head gasket into the cylinders but just condensation in the exhaust pipes burning off till warmed up.

Or a compression test could be useful in diagnosing the engine.

kevkon didn't you mean?
white smoke=coolant
blue smoke=oil
black smoke=excessive fuel

[Nium]

Too quick on the keyboard

Sorry, I hadn't noticed you had already written that the white smoke had stopped when you turned the adjustment screw.

An old school trick you might could try, with the engine at operating temperature and running, slowly pour a full cup (8 oz) of water down the carburetter throat. The water will turn to steam in the cylinder and help to loosen up carbon deposits and break them up so they are blown out the exhaust. You just have to pour slowly, just a little trickle, till it's all gone. You don't want to stall the engine.

[NelsAnderson]

I probably got the color of the smoke wrong. It was rather cloudy and dark when I was working (needed a light under the hood to see the engine). But I think the key is:

No smoke initially.

Enlarged hole in primary jet: smoke from exhaust started.

Turned in mixture screw: smoke stopped.

Unless I'm really clueless on this, that pretty much means the mixture got too rich when the jet was opened up.

So I think more cleaning of the carb is the next step. The cup of water down the throat it something I wouldn't have thought of but I'll give that a try...thanks!

I'm still unclear about the other jets and passages. Is that a second jet at the bottom of the bowl I need to remove and clean? Can the air correction jet just be unscrewed and cleaned? How do you remove the pump jet? That probably needs cleaning too.

[jac04]

Here is some good info:

http://www.aloharovers.com/tech/ichoverhaul.htm

[NelsAnderson]

Here is some good info:
http://www.aloharovers.com/tech/ichoverhaul.htm

Oh, that is a good article, thank you.

Well, I made use of that. Didn't do the whole tear down and rebuild but did use it as a reference to open up the carb, remove things and blow them out. The only thing that still stumped me was how to remove the air tube. The air jet that's right above it unscrews and comes out but then the air tube is sitting there down inside the cavity with nothing to pull on to get it out. So all I could do with that was blow carb cleaner through it while it was in place.

Well, after blowing out everything that I could remove and re-adjusting the idle speed and mixture, the end result is that nothing has changed. It runs just as rough as when I started. I really thought finding and clearing the clogged main jet I was on to something but clearing that didn't actually do anything other than make it run rich :-(