Rough Idle - Dirty Carb or Something Worse?

[l008com]

I haven't had time to even try to start this machine yet. But I was sitting around yesterday and I realized that the rocker would have fallen off when I took the engine cover off. Meaning the rocker isn't the problem and I fully expect this thing to run like crap again once I try to start it up. Guess I'll drain the tank again and try to clean the carb again. Even if I don't get it to 100%, I guess any change in the way it runs will indicate its carb related, and no change at all will indicate its something else.

 

[slomo]

Plug gap looks too tight. Open her up to your engine spec from your engine manual. Most are 30 thou. Check you manual out. Get rid of that Champion plug while you are at it.

Valves look okay. Can you spin a valve with your thumb, valves closed? If so the valves need lapped and are not sealing.

Rockers come off due to retaining screws backing off or when most everyone on Earth neglects their cooling fins. Valve guides can move from over-heating the engine. Mostly due from lack of maintenance. Need to check the valves YEARLY for a good running machine. Takes 5 minutes out of your busy day. Perfect winter project.

 

[slomo]

So it felt like the set screws had loosened up a lot, even though I had tightened them good and snug with my T10. I re-tighten them after I readjusted them, squeezing as hard as I could with my T10 driver but no luck. Is there a trick to this? The first T10 (bit) I used snapped when I was trying to initially loosen them. I can't get them back that tight, not with my hand driver anyway.

Hand driver is plenty tight. Make sure the rocker stud is tight and thread locked in. You don't need NASCAR torque on any of these tiny bolts/nuts.

 

[slomo]

Another thing I don't udnerstand. I was able to pull the cord and get the machine to fire a few times before it died again.
If the intake vale is stuck closed because the rocker isn't touching it, how was the engine able to run at all? That doesn't make sense to me?

Might have residual fuel in the chamber lighting off. Nothing to worry about.

 

[slomo]

Make sure the valve cover is NOT dented inwards. It can and will hold a valve or two open.

 

[l008com]

The rocker issue was just because I took the engine over off and didn't realize that removed the pressure holding the rocker on to the rods.

So I'm just going to drain the fuel tank again, remove and clean the carb again, and see what happens. The fuel tank looked plenty clean to me, but maybe since it will be empty anyway, I'll clean it with some soapy water.
Then I'm going to put the same fuel back in. That fuel is not old, it's new. But its been in a tank that theoretically could be dirty. So it could have some dirt in it. SOOO whats a good say to strain the fuel, as a precaution? Like a coffee filter maybe? Something like that?

 

[slomo]

The rocker issue was just because I took the engine over off and didn't realize that removed the pressure holding the rocker on to the rods.

Do you mean valve cover? If so the valve cover doesn't hold anything on other than itself and or maybe a gasket.

So I'm just going to drain the fuel tank again, remove and clean the carb again, and see what happens. The fuel tank looked plenty clean to me, but maybe since it will be empty anyway, I'll clean it with some soapy water.

You need to FLUSH, BLOW and reverse blow the tank out. If you have a 90 degree hose barb on the tank outlet, make sure you have flow there as in a good solid stream. Be looking at where you can't see inside the tank. Not just in the bottom and call it good.

Then I'm going to put the same fuel back in. That fuel is not old, it's new. But its been in a tank that theoretically could be dirty. So it could have some dirt in it. SOOO whats a good say to strain the fuel, as a precaution? Like a coffee filter maybe? Something like that?

Not advised. Any grit being smaller than you and I can see will go right back in where you don't want it to.

 

[l008com]

Last night, I took the tank and carb off again. I soaked the jet in carb cleaner, then sprayed out all the holes and all of the bowl and body of the carb again. Then I put hot water and some dish soap in the tank and shook it vigorously. Repeat a bunch of times. Then flush with tap water for a while.

This tank is as clean as I can possibly get it, as is the carb.

Right now its sitting out back drying out. Tomorrow or the next day, I'll throw gas in and pull the cord and see what happens. Hopefully it starts right up and stays running.

 

[Auto Doc's]

This may sound strange but pull the muffler off and heat it up really well with a torch to burn out any oil and carbon that has likely collected in it. If exhaust cannot get out, fresh air cannot get in, I deal with this issue more often than I like these days.

Also sharpen and balance the blade or replace it. Being a junk rescue, there is no telling what could have happened with the blade before you got it.

Last but not least, does it need a valve adjustment? This is a maintenance step that is often overlooked or avoided. There are plenty of videos online that demonstrate the procedure, you just need to make sure you find the video that applies to this particular engine. Most of them I deal with gap at .005 inch.

This engine likely has a compression release mechanism on the camshaft, so conducting a compression test would show to be lower than what you would expect to see.

 

[l008com]

This has been an ongoing saga, I've already done all of those things at this point. Except testing compression, I still don't have a gauge. The machine isn't in that bad of shape probably because it's only 6 years old.