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Discussion Starter #1 (Edited)
CCR 2000 4.5HP Model 38180 Serial 5921418
Single Stage Two-stroke Engine

Having problems tuning this brand new carburetor. It does NOT have the EPA limits on the pilot adjust so that should help.

BTW: I am at 5000' altitude in Denver, it's 85 degrees outside. Fuel is fresh. Carb is brand new.

First of all I cannot get the engine to run unless I have a little bit of choke.
Traditionally that's your cue to make the mixture a bit richer.
However, there is no setting on the pilot adjuster that works when the choke is totally off.
I've tried the full range of motion for that screw.

So I gave in and thought... OK, I'm willing to live with that if I have to. I don't see any other choice. I don't want to start re-drilling jets on a NEW carburetor.

So then I tried to tune the carb even though the choke was on just a tad (because that's the only choke setting that runs).

I can't do the usual "left until fails" "right until fails" "go for the middle" "extra 1/8th to the left"
For some reason, there's a whole range of motion in the pilot screw that seems OK... not great.. but OK. Outside that wide range it just dies or the screw some out!
BTW I'm waiting for a few minutes between tweaks to let everything settle down.
So, with nothing better to guide me... I've tried to go for the center of that OK range.

I then let it sit there and run (hoping for 10 minutes) however, the engine runs OK (I suppose) for quite some time but then after 5 minutes, the engine starts to hunt and then stalls.
No tweak on the pilot jet seems to stop that 5 minute stall.
AFAIK the carb bowl is not emptying during that 5 minutes. I've looked inside and the float moves up and down taking the needle with it. Needle is not sticking.
The range of motion is smaller than I'm used to seeing due to the plastic "spacer" that acts as a stop... however, if that's the way it's designed.. it should be OK.

Do any of these symptoms mean anything to anyone?
I'm at the point where I'm thinking I'll just put this machine to one side and wait until the weather gets colder and see if something magically changes.

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One thought is a possible vacuum leak. That would explain the need for choke (maybe). I guess I should spray carb cleaner around the carb-manifold gaskets to
see if that changes anything if the carb cleaner gets sucked in along with the (potential) air leak. The gaskets looked OK.. not too compressed and skinny.... but they are not new. Everything is snugged but not over-tightened.
However I can't see a 5 minute fail using that story.
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One random thought I had is that a coil getting hot may act flaky, but I wouldn't have predicted that to cause hunting then stalling.
Plus, the engine was hot to begin with.. it's not as if the coil was cold and then warmed up for 5 minutes.
Hunting then stalling sounds more fuel-related.
 

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what do the fuel lines look like? i've seen many a 2 stroke not run right due to the lines sucking in and what looked like a good fuel filter being clogged all thanks to this junk now called gasoline,
yes i to would spray choke cleaner around all the gaskets and rubbers,
 

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Discussion Starter #3 (Edited)
what do the fuel lines look like? i've seen many a 2 stroke not run right due to the lines sucking in and what looked like a good fuel filter being clogged all thanks to this junk now called gasoline,
yes i to would spray choke cleaner around all the gaskets and rubbers,
Thanks.. I didn't say it... but I changed the fuel line and intentionally took the fuel filter out for that very reason. I intended to reinstall a new fuel filter once I got it running.

The 5 minute thing still makes me wonder about the possibility of an empty bowl (even though I specifically checked for the needle sticking etc).
Are you familiar with these carbs? The full-range motion of the float is really tiny. I guess it only needs to be just enough to open and just enough to close... but that range is much smaller than I've seen before on the free-dangling floats. It's also smaller than I've seen on Honda lawnmowers that also have a float-stop (I prefer that term.. it means more to me than "spacer").
I thought about taking off the "float-stop" .... but when I did that... the range of motion was still small anyway. Are these carburetors always so small with the float displacement? Maybe I got a lemon carburetor? Just clutching at straws here.

EDIT: I guess what I COULD do is run it until it stalls then immediately clamp the fuel line and check to see if the bowl is empty... It would confirm or eliminate the empty-bowl theory.
 

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Discussion Starter #4 (Edited)
Well.... It's been running for 10 minutes and it's still running as I type.
Three things have changed... I will need to eliminate them to see which fixed it..

1) It's a few degrees cooler now the sun is setting (75 not 85)
2) I removed the float-stop which gave a tiny bit more motion on the float (I mean part 27 on the image)
3) I loosened the gas cap slightly in case the vent hole was somehow trapped against the threads

One of those three seemed to fix it (or this thing has a mind of its own and it's just messing with me) ;-)

EDIT: BTW it survived the vacuum leak test (carb spray around the gaskets)
When it stalled and I clamped the fuel line... the bowl wasn't empty... but I don't think I got a full bowl of gas when I took off the bowl
 

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Discussion Starter #5
So today is a cooler day. 60 degrees.
I re-tightened the gas cap to eliminate that from the equation.
The engine is still running and not stalling out so I conclude the "fix" was to remove the float-stop.
It's strange that I had to do that to get some meaningful motion on that float and the float needle.
Oh well.. it's running now.
 

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On my phone waiting on a appt so not a good time to explain how to do it but have you checked the float hight to make sure its opening as it should, Just search youtube and it will explain the how too, rather easy and even though its running now it may run dry once you load up the machine and its drawing more fuel.
 

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Discussion Starter #7 (Edited)
On my phone waiting on a appt so not a good time to explain how to do it but have you checked the float hight to make sure its opening as it should, Just search youtube and it will explain the how too, rather easy and even though its running now it may run dry once you load up the machine and its drawing more fuel.
That would be nice... but there's nothing adjustable.

It's a plastic float and doesn't have a metal tang that can be bent up and down. The tang is just a fork in the plastic and would snap if you tried. I guess you could try to melt the plastic to adjust the angle of the plastic tang but I'm not going down that route.

The only thing that comes close to a float adjustment is the stop. There's only two choices (a) use the float stop (b) take it out.
Like I was saying earlier, there's just too little motion with that float if the stop is left in to truly open up the gas flow.

The other thing that might possibly work is to intentionally squish the needle into the seat to try to flatten it or make it more "open" but I didn't want to end up with a brand-new carburetor that floods and never shuts off the fuel flow because I've trashed the needle seat.

BTW It shouldn't dry out with the stop removed.. if anything, you'd have the opposite problem because the float hangs lower.
However the float doesn't drop too low even without the stop so it should be fine.
 

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AH I see, I've seen a few but most have the metal tap for the needle, Didn't think about the few out there that are plastic. OH How did the carb work out that you had asked me about for a 10hp Tec eng I think it was. Did it work well for you.
 

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Discussion Starter #9 (Edited)
AH I see, I've seen a few but most have the metal tap for the needle, Didn't think about the few out there that are plastic. OH How did the carb work out that you had asked me about for a 10hp Tec eng I think it was. Did it work well for you.
Snapper 1030: Adjustable Carb
Yes and No... The new carb is on and the engine runs.. but that one too needs a slight amount of choke... just a fraction. No amount of unscrewing on the main jet compensates for the lean mix. Strange but true. There's also lots of coughing too as it runs (which you'd almost expect if the choke is not fully off). I'm wondering if the altitude and high summer temperatures are having some effect and that things may be better in the winter. Of course, the engine may also be a bit worn out as well (valves etc).
I'm going to get a couple of brand new sparkplugs too just to give it the best chance of getting good combustion.
The existing plug is NGK so it seems a pity to pull it but I won't know until I at least try it.
 

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Did you richen the low speed any, These engines DO feed off the low speed even when full throttle with no load on them. Had a powersmart I worked on that no matter what you did seemed to be hunting for gas at full throttle, I drilled out the low speed jet .003 larger (I am a machinist so this stuff comes easy to me) But the jet was .018 and I drilled it to .021 and I put it in and started first pull and all hunting was gone. (If you're not sure what hunting is, It's a term used when the engine is pulsing up and down, Running off the gas in the engine then starving for gas and pulsing when more gas goes in.) But I would try richening it up a little to see if it improves.
 

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Discussion Starter #11 (Edited)
Did you richen the low speed any, These engines DO feed off the low speed even when full throttle with no load on them. Had a powersmart I worked on that no matter what you did seemed to be hunting for gas at full throttle, I drilled out the low speed jet .003 larger (I am a machinist so this stuff comes easy to me) But the jet was .018 and I drilled it to .021 and I put it in and started first pull and all hunting was gone. (If you're not sure what hunting is, It's a term used when the engine is pulsing up and down, Running off the gas in the engine then starving for gas and pulsing when more gas goes in.) But I would try richening it up a little to see if it improves.
Snapper 1030: Adjustable Carb
BTW we are talking on the wrong thread here :) That might confuse anyone coming along later. We are now talking Snapper 1030. :)
Yep.. tried all permutations of main jet and idle jet... at least I believe I did. I'll be giving it one more time around the tuning loop. 5000'elevation isn't all that high and should be in range for the 1030 adjustable carb. It's good enough for now.. it's running but it just doesn't have that new engine purr...but it's not a new engine. ;-) I'll have to re-tune when the winter temperatures kick in anyway so I think I'll put this on the back-burner for now.

Toro 5/21: Fixed Carb
may eventually think about a re-drill on the other carb I had bought (fixed jet). I prefer to keep that option to last though especially on a new carb.
 

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that should have a adjustable needle, A redrill is for a fixed jet. But yes wrong thread but if they read the thread they should know what is being talked about.
 

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Discussion Starter #13 (Edited)
that should have a adjustable needle, A redrill is for a fixed jet. But yes wrong thread but if they read the thread they should know what is being talked about.
Toro 5/21: Fixed Carb
LOL ...I was meaning drilling the fixed-jet carb I bought last week (or the week before) for my other Toro 5/21... the fixed-jet carb was a big mistake.... my first and last ever fixed-jet carb.
Not a chance of it running here at 5000'... it's just too lean and no way to adjust it....except for a re-drill.
Oh well, it was only $10 or$15...lesson learned.

Those last few posts were for Snapper 1030 and now a Toro 5/21 ;-)
I'm working on too many machines at once here. That's why I like to keep the threads straight.
Let's get this thread back onto CCR 2000 :)
 

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Discussion Starter #14
Toro CCR 2000:
So one last question for the CCR 2000 - has anyone else had this problem and needed to pull off the choke-stop to get enough flow into the carb bowl?
I'm ok with the machine the way I have it... but it seems wrong to need to do that.
 
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