Champion 3000 (RW) generator, won't start Pt. 2

[skeer]

Since the original thread started getting heavy, I thought i best to start a new one, especially since the actual question at that time was different than now.

Champion genny circa 2006-ish, won't start. It was backfiring but so far today it hasn't.

What's been done:

Carb, Re-pulled carb, all the accessible jets are clear. Float should be good.. it's not really adjustable like the Briggs style where the metal tab can be better to adjust float height.

Spark. Full and strong. Validated both with a Briggs spark tester.. the one with the light that is plugged between cable boot and plug. And by holding the electrode against ground.

Fuel delivery. *note that I did NOT say "proper air/fuel mixture". But the plug gets wet with gas. Does this mean the carb is working like it should be? No but worth mentioning.

Flywheel Key, not sheared. Pulled the FW, all is normal.. some rust but even after wire-wheeling that it was good.

Starter Fluid, Tried a healthy dose since non-chlorinated 'brake cleen' wasn't good enough.


With the pull cord assembly removed from the flywheel I can rotate the cam by hand. Now I don;t mean spin it like a 'Wheel of Fortune' but I can easily rotate it. Meaning, it's only a 196cc engine but I'm expecting compression and I don't feel it.

 

[metalmagpie]

I'm no small engine guru but it seems to me you should pull the head.

 

[skeer]

Actually.. just did that. Did not see anything out of the ordinary.

 

[gizardlizard]

When small engines sit for any length of time with fuel in the carb, the carb gets gummed up. It’s almost a guarantee. This is why, when people go to start a small engine for the first time in a long time, and it doesn’t start they tell themselves “ it ran great when I used it last.” Whenever I hear this, it’s literally 10 times out of time a carb issue. The carb needs complete disassembly and cleaning. Spraying a little carb cleaner isn’t good enough. Some passages can get so gummed up, spray isn’t enough and you need soft brushes or wires.

 

[BurtEggley]

fuel to air is usually what it is when there is proper spark. That said. check the timing against the piston rise to see if it makes sense - meaning check to see if the timing of the strokes matches the valve timing. The youtube guy I suggested explained how to check it accurately but I won't waste time suggesting him again. Looks like you will eventually figure it out.

 

[pbon]

I have a 3000w generator that would not start. A $20 replacement carb from Amazon fixed it. Had a leaf blower that would not start. New fuel lines into the tank and a new carb fixed it.

 

[PoorUB]

Something weird like valve timing?

Some of these newer engines have "plastic" cam shafts and cam gears. They can slip or strip and get out of time. The easy way to check valve timing is to roll the engine over slowly and there is a point when the exhaust valve is closing and the intake valve opening. At that time the piston should be right at the top of the cylinder, right at top dead center. If it isn't, you have internal cam issues.

 

[carlaisle]

With the pull cord assembly removed from the flywheel I can rotate the cam by hand. Now I don;t mean spin it like a 'Wheel of Fortune' but I can easily rotate it. Meaning, it's only a 196cc engine but I'm expecting compression and I don't feel it.

How are you rotating the cam by hand?

Starter Fluid, Tried a healthy dose since non-chlorinated 'brake cleen' wasn't good enough.

Can you quantify a "healthy dose"? If it won't run on ether it won't run on gasoline.

 

[finn]

Check the valve lash, unless you did and I missed it.

Also, old fuel can gum up the valve springs and screw up compression. Just found this to be an issue on the neighbors 34 Plymouth. Ran great, but wouldn’t start the next loaning. Sticky / gummy fuel residue on the valve stems.held the valves open.

Pull the wire from the oil level sensor. I doubt that’s the issue, as I don’t see how you would have any spark, even when just pulling it over, and I doubt there’s any fancy circuits that would give spark when cranking, but none when running, like a bad ballast resistor on an older car.

 

[BurtEggley]

here is one that would not start

 

[Mike65]

I have a 3000w generator that would not start. A $20 replacement carb from Amazon fixed it. Had a leaf blower that would not start. New fuel lines into the tank and a new carb fixed it.

When I lived in NJ, we had an older snow blower that was having starting/running problem & I put on a new carb & it fixed the problem. I would get a replacement carb.

 

[robin1731]

Not familiar with these but is there only a lash cap on the one valve and not the other? In the pic there is only one.

 

[Axehandle2]

Replace the spark plug.

 

[firebirdparts]

here is one that would not start

43 minutes? Holy cow.

 

[skeer]

Not familiar with these but is there only a lash cap on the one valve and not the other? In the pic there is only one.

Are you talking about red versus blue?

 

[skeer]

How are you rotating the cam by hand?


Can you quantify a "healthy dose"? If it won't run on ether it won't run on gasoline.

By turning the flywheel by hand. Sorry if it sounded like I was grabbing the crankshaft directly.

 

[skeer]

Something weird like valve timing?

Some of these newer engines have "plastic" cam shafts and cam gears. They can slip or strip and get out of time. The easy way to check valve timing is to roll the engine over slowly and there is a point when the exhaust valve is closing and the intake valve opening. At that time the piston should be right at the top of the cylinder, right at top dead center. If it isn't, you have internal cam issues.

This is exactly what I'm thinking now. I have noticed the exhaust open, then close and right before it's closed the intake begins opening. But the weird spot is when the intake closes the exhaust has this small bump that is probably enough to cause an escape during the compression stroke.
I need to get the head bolted back on and snap a video of it.

 

[hobie18]

Is the emulsion tube clear? Push down from carb throat. After loosening the jet.

 

[PoorUB]

But the weird spot is when the intake closes the exhaust has this small bump that is probably enough to cause an escape during the compression stroke.

That is a normal compression release. There is a small spring loaded flyweight on the exhaust cam that holds a small ramp that bumps the exhaust valve slightly on the compression stroke. When the engine starts the flyweight over comes the spring tension the the ramp drops away from the cam allowing the valve to stay closed.

Here is one style, there are multiple variations.

 

[Metal-Marc]

When small engines sit for any length of time with fuel in the carb, the carb gets gummed up. It’s almost a guarantee. This is why, when people go to start a small engine for the first time in a long time, and it doesn’t start they tell themselves “ it ran great when I used it last.” Whenever I hear this, it’s literally 10 times out of time a carb issue. The carb needs complete disassembly and cleaning. Spraying a little carb cleaner isn’t good enough. Some passages can get so gummed up, spray isn’t enough and you need soft brushes or wires.

An ultra sonic cleaning bath is the way to go when rebuilding a carb.

Often times, it's just faster and cheaper to replace the carb with a new unit. Beware of Chinese junk on amazon.

 

[robin1731]

Yes, you can see the one tone adjuster screw is out a lot further than the other one too.

 

[robin1731]

Are you talking about red versus blue?

Yes, you can see where the one adjuster screw (red) is out a lot further than the other one also.

 

[BurtEggley]

The flats on the spring retainers have specific positions too. James Condon went into it on one of his generator episodes and the consequences of it not being clocked right. Same for the lash cap / no lash cap thing. I don't know, this thread is off the rails and impossible really to follow. I am used to a systematic method of trouble shooting rather than firing the what does this do cannon. Good luck.

 

[skeer]

Yes, you can see the one tone adjuster screw is out a lot further than the other one too.

I noticed that.. both lock nuts and the screws themselves are good and tight.

 

[robin1731]

I noticed that.. both lock nuts and the screws themselves are good and tight.

Did you check the valve lash? Seems like the adjuster on the left should be out further than the one on the right since the left has no lash cap and the right does. Unless there is a reason they are done that way. Like I said, I have no experience with this engine but i do work on a lot other engines that use adjuster screws like that.

 

[skeer]

So there’s only the one valve stem cap(?) you can tell from the wear that that intake side never had one. I removed the cap for this pic, it was covering the valve at the top

 

[skeer]

As far as lash goes, once re-assembled there is a small amount on the intake side. Couldn't find my feelers yesterday but it wasn't much. Exhaust side was tight. It's possible I got the push rods swapped.

 

[skeer]

Ugh.. I think I'm done with this thing. Put it all back together after re-checking all the carb jets and passageways. Still back fires right out of the intake. Maybe I can get 50 bucks for it,

 

[theoldwizard1]

An ultra sonic cleaning bath is the way to go when rebuilding a carb.

Pricey !

Remove all "rubber" components, including the needle valve. Remove main jet (requires a special screwdriver) and emulsion tube. Probe ALL passages with a fine stiff wire (single strand from a wire brush).

Often times, it's just faster and cheaper to replace the carb with a new unit. Beware of Chinese junk on amazon.

Unless you are willing to pay the price for a genuine OEM replacement, anything else is has, at best, a 50/50 chance of working well.

 

[no704]

Throw a cheap carb on it as you have been told from the start.