Starting issues YM2000

[Car Doc]

Ok so I got the exhaust manifold off and I also got a video see what you guys think.

YouTube - 20110320_201551.mpg

Man you have an exhaust valve that is not seating it may be bent, sticking or has a chunk melted out but thats what it is!!! (see my air test above to prove it) I think the head needs to come off. my 2c

I also agree it sounds like it has plenty of compression in the one cyl that is making compression but it will never run like that.

 

[YM200inGA]

It does spin faster with the decomp off but I have been wondering if it still isn't faster enough. Maybe the car I am using doesn't have enough amps even when it is running.

 

[YM200inGA]

Man you have an exhaust valve that is not seating it may be bent, sticking or has a chunk melted out but thats what it is!!! (see my air test above to prove it) I think the head needs to come off. my 2c

I also agree it sounds like it has plenty of compression in the one cyl that is making compression but it will never run like that.

Not sure what you mean by see my air test above. Am I missing something?

 

[Car Doc]

Not sure what you mean by see my air test above. Am I missing something?

I can tell you how to determine where the leak is --- once you get an adapter to fit properly just back the valves off and air the cylinder up with shop air but keep hands away from the fan and belts and make sure its in neutral it will lurch when the piston is shoved to the bottom of the cyl...air will either be coming out the intake or exhaust or the crankcase take it from there hth.

I am actually referring to your compression tester that you could adapt it to hook up an air compressor to pressurize each cylinder and with the valves backed off so no valve movement can occur when the engine is turned then the "air leak" will be obvious at one of the 3 spots I mention.

We call it an air test sorry I am short on preliminary material sometimes when I am teaching someone to do something I do on a regular basis.

 

[YM200inGA]

Maybe its just because I don't work on these very often but that was as clear as mud. what do you mean back the valves off? Also shouldn't the air always come out one of the valves based on whether the intake or exhaust are open?

Thanks

 

[284 International]

YM200inGA, what he's saying is to set up the machine so that both valves are closed, then pressurize the cylinder using your compression tester. On some engines, you can loosen the rocker arm so that the valve is not activated by "backing off" the nut that holds the rocker arm in contact with the valve.

Our YM2000s don't have that mechanism. On these, the rocker arms are on shafts. The equivalent procedure would be to pull off the retainer for the rocker arms, then just slide them off sideways. That keeps both valves held closed by the springs the whole time.

Once it's pressurized by the tester, the air will have to escape, somewhere. It will either leak through the exhaust valve, thus emerging through the exhaust side, or through the intake valve, detectable by air through the intake, or out the piston, whether by faulty rings or a damaged piston, and leak out the crankcase vent/oil dipstick.

The pressurized air will also drive the piston to the bottom of its stroke, hence the warning to keep hands free of the fan and the machine out of gear.

 

[winston1]

As most would suspect, let me butt in too. Just to say the reason for sliding the rocker arm over is because when the air pushes the piston to the bottom it will likely cause a valve to open if the rocker arm is in place.

 

[Car Doc]

Thanks you guys right on!

(I don't use the internet after 5 pm when I go home! )

 

[winston1]

YM2000inGA, Got an update for us? We are itching to see this 2000 running.:thumbsup: