J’s dirty 30

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The pop off pressure must have been around 30psi, a lot higher than the ~25 it is now after trimming the spring. I still have some work to do. The screw that holds down the metering arm and pin snapped leaving the threads in the hole. I used a grabber bit at and got it out but I don’t have a screw, I’ll have to check the hardware store tomorrow
 
I got it out easily. The threads seem fine. It’s the same pitch as the screws that hold down the primer bulb
The last time I tested pressure it popped around 25 or so. This must have been the issue all along. Before I clipped the spring it wouldn’t pop at 25
 
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That's good so atleast you got it fixed and adjusted. See how 25psi does for you, I usually go for 20-22 but I'm interested to see how it does for you.
 
Well I found success in trimming the metering spring down to a roughly 22 psi pop off pressure, but in the end the carb floods anyway. The inside of the air cleaner is saturated with fuel.
I’m at a loss here now.
It bugs me that I can’t get it to idle on its own, I have to constantly rev it or keep the throttle open. Then I’m afraid of going too lean.
 
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I pulled the motor out to check the air gap on the coil since I’m sure my pop off pressure is good. I set the coil gap using a business card. I tried to fire it up after installation and it immediately went to that flooding/running like crap symptom I see after a short amount of time driving it. I tried a second time with the card doubled up and it was the same thing.
What is too thick or too thin of a gap?
 
Rep732 said:
Man I'd cut your losses and throw that engine right in the garbage. Get a 32/34cc zenoah and call it a day.
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Well said.
Dunc2504 said:
I think I would try a fresh carb and try it with the air filter off.
I had NO problems with either of my 30DN 38s.
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ill try a genuine Walbro carb, I’m sure this is a clone.
 
Before I go scrapping the engine I’d like to figure out what the real issue is.
It runs great until the bogging down occurs, it’s an obvious flooding problem.
I also wonder about weak spark? See video above, the video is shakey but you can see the spark has some orange in it. Brand new plug right there.
 
@Dirty30J the spark looks ok to me, you can try a new carb "1107" and see how it does. Unfortunately the pop pressure needs to be adjusted with a new walbro, I literally just adjusted one on a dbxl 2.0 with one run on it out of the box. As for why yours floods I have no idea but a clone carb I wouldn't trust.
 
I dropped a little fuel in the cylinder and it fired up briefly. However when it wouldn’t start after a few more pulls I removed the spark plug and it was pretty wet.
I don’t really get it, I dump gas in the cylinder and it fired, yet it has the appearance of being a flooding issue.
 
That spark "test" doesn't tell.you anything other then the plug will fire in the air. Not under compression or in a combustion chamber. Need a spark tester to properly test an ignition system.
Not the best one out there, but the cheap ones work just fine for occasional use.
【The Best Deal】OriGlam Spark Plug Tester, Adjustable Ignition System Coil Tester, Coil-on Plug Ignition Spark Circuit Tester, Autos Diagnostic Test Tool https://a.co/d/bqfism6
 
Seandonato73 said:
That spark "test" doesn't tell.you anything other then the plug will fire in the air. Not under compression or in a combustion chamber. Need a spark tester to properly test an ignition system.
Not the best one out there, but the cheap ones work just fine for occasional use.
【The Best Deal】OriGlam Spark Plug Tester, Adjustable Ignition System Coil Tester, Coil-on Plug Ignition Spark Circuit Tester, Autos Diagnostic Test Tool https://a.co/d/bqfism6
Click to expand...
I’m going to get something a lot like that tomorrow
 
For me it is all pointing to the carb.
These are just simple 2 stroke engines , so as long as you have compression , fuel and sparks there should not be a problem .
The standard carb is billed as a Walbro product , but it could have a defect , it would be my first port of call every time for this sort of issue , especially as you suspect flooding and cannot get base settings to work. My 2 38s have been totally reliable for starting and running.
 
Dirty30J said:
I’m going to get something a lot like that tomorrow
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there are a few variations of them, they all do the same basic thing. Simulate in cylinder conditions to the ignition system, or stress test it. You just can't do that with a normal plug gap in free air. Cheap, easy to use. If it jumps the gap at the sm (small engine) position or longer, the ignition system is working fine. Spark plug may be suspect, but it's easy enough to have a spare plug laying about.
Dunc2504 said:
For me it is all pointing to the carb.
These are just simple 2 stroke engines , so as long as you have compression , fuel and sparks there should not be a problem .
The standard carb is billed as a Walbro product , but it could have a defect , it would be my first port of call every time for this sort of issue , especially as you suspect flooding and cannot get base settings to work. My 2 38s have been totally reliable for starting and running.
Click to expand...
Few years ago now I got to email back and forth with the walbro tech department. They did confirm they make carbs for rovan and a few other Companies, also confirmed a short list of carbs labeled as walbro being genuine and confirmed an 1191 is the same spec as an 1107. The 998 was on the list as well.
 
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Dunc2504 said:
For me it is all pointing to the carb.
These are just simple 2 stroke engines , so as long as you have compression , fuel and sparks there should not be a problem .
The standard carb is billed as a Walbro product , but it could have a defect , it would be my first port of call every time for this sort of issue , especially as you suspect flooding and cannot get base settings to work. My 2 38s have been totally reliable for starting and running.
Click to expand...
That is good to know your engines have been good. They do have a line that go into the Chinese stuff. My carb is the 1191 or 1107 if it was on a zenoah.
Seandonato73 said:
there are a few variations of them, they all do the same basic thing. Simulate in cylinder conditions to the ignition system, or stress test it. You just can't do that with a normal plug gap in free air. Cheap, easy to use. If it jumps the gap at the sm (small engine) position or longer, the ignition system is working fine. Spark plug may be suspect, but it's easy enough to have a spare plug laying about.

Few years ago now I got to email back and forth with the walbro tech department. They did confirm they make carbs for rovan and a few other Companies, also confirmed a short list of carbs labeled as walbro being genuine and confirmed an 1191 is the same spec as an 1107. The 998 was on the list as well.
Click to expand...
That was a brand new plug, didn’t even make it into the cylinder head yet. I was simply comparing a new one with one I was using that I cleaned because it was wet with fuel. I decided to make a video and post it up just for sanity’s sake.
My carb is stamped as the 1191 and even has the Japan stamp on it. It looks legit but could have a poor seal at the metering needle seat?
If my spark checks out with a tester then I think we can dig into the carb. I took it off and sprayed cleaner in all the orifices thinking it could be clogged.
 
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