OK so I put a new longer post line on so I could turn this Amazon fuel pump the opposite way it was before, it outperformed my Honda fuel pump,So I guess the question is would it perform this well under load when you’re driving it?
I Got 4 ounces both ways, 4 ounces coming from the line that goes to the TV and 4 ounces out of the gas line going to the carb,The last test I did with the Honda fuel pump I think the most I got was 4 ounces to the carb and only 2 ounces out of the line that goes to T

1) Compression testers: There is a thread here on compression testers because of the quality of some of these things. You will get different readings based on the quality of a tester.

2) You are getting 4 oz flow: I would try it but if anything is funny at the top end I would limp home. I bet it's good.

3) I know you just have that pump hooked up temporary but you have to keep something in mind. These engines only put out 5 psi pressure and 5" to 7" of vacuum (I measured it). I call it 5&5.
With very low pressures like that if there is ANY leak ANYWHERE it's over. Those clamps look very suspect and I see NO clamp on your vacuum line. There better be one on the vacuum line connected to the Engine. Further more I was reading some ultralight aircraft accident reports online. These guys run vacuum pumps same type we use. It was some interesting reading. Clamps came up in the accident investigation.

4) Avgas or better based on compression: Not sure what to suggest here. My brothers super Engine has 175 lbs compression (measured with a good American made tester) and we run Avgas no problem. If you have been running it in the past with no poofkaboom then you're good.
CO

Ok thanks
Yes I had a clamp on the pulse line on the Engine but not on the pump because that hose was so tight getting over the pump I figured it was good enough.I do have two clamps on the other pulse line when it is hooked up.

Yes I ran av gas before but the compression wasn't quite this high before,I think 180.

So I went ahead and drove it down the street with the new fuel pump with the same results(still missing at high rpms)
So it had 188 main jet,I got 3 new jets in mail,biggest one being 205,I put it in, couple laps down the street with the same result, still missing at high rpms.
My neighbor was outside watching me for the last couple of runs and he came down and he thinks the same thing that I have been thinking that it something electronic.
With all the carburetor changes, fuel pump changes, nothing has changed, it has pretty much ran exactly the same with very little change in performance,but that miss has remained the one constant

Could be the stator.

viewtopic.php?f=25&t=17418&start=0

viewtopic.php?f=5&t=17899&hilit=bird&start=200
Go to the last page on this one if you want.

https://www.regulatorrectifier.com/cata ... 8f&x=0&y=0

CO

EDIT: I am not trying to be a smrtazz but did you change the plug ??
If it was me I would put a new plug in AND try another ignition coil if you have one laying around just to be sure. It's easier than changing a stator. Also close up the sparkplug gap a bit. Make sure the ground wire to the Engine has good contact.
CO

No I don’t think you’re being a smart ass, no I did not change the plug, the plug looked fine when I did a compression test but I will put another one in just to be sure but I have zero faith in that changing anything.
I sure hope it’s not the stator because that would be the hardest thing to change out and probably the most expensive,I am pretty sure I can get my parts guy to send me another CDI (Capacitor Discharge Ignition) and coil to test So I’m going to do that
Thanks

Nick is sending me a coil,CDI (Capacitor Discharge Ignition),timer and rectifier to see if it is one of those,if none of those make a difference probably try a stator

So things are not working out for me :(
Got the electrical parts in from Nick.Decided to jack the back wheels off the ground to do testing rather then driving it up and down the street and pissing off the neighbors.
So first test was to see if it would still miss at full throttle with wheels jacked up just like it would if I was driving it,and it did.
So I thought the first thing I would switch out would be the coil. So I hooked up the coil that Nick sent me and it was still missing. So I remembered that CO Asked me if I had change the spark plug and I had not so I went ahead and change the plug and did another test and it was still missing.
I just got a brand new belt in the mail so I went ahead and installed it while I was messing around.
Did Another test only this time I decided instead of going straight to full throttle to take it up to half throttle and hold it there for about 10 seconds and then slowly go to full throttle from there,and I did and it didn’t miss! So hmmm wtf? I did that a couple times with same success so then I tried it Giving it full throttle right from the get go and it had a little miss for a second or so but then cleared out And was running great without a miss at full throttle. So when I get off throttle and it’s idling I start hearing a screeching noise that sounds like it’s coming from the clutch,so I blip the throttle and it stops.
So then I decide to put my old coil back on and see if it will miss again at full throttle or if the new coil fixed the problem. So With old coil installed I take it up to half throttle for about 10 seconds and then go in it and it’s not missing now either,wtf? Why is it suddenly not missing? So I take it up to full throttle right from the get go and it’s not missing! So I let off the throttle back down to idle and the clutch is screeching loud as hell again. So I spray some comet clutch lube on it to see if that will do anything,It does not. The screeching is not constant, only at idle, and if you blip the throttle it will go away.
So now the bad part.I start it again And this time it revs up on its own like I’ve got throttle pegged but I’m not giving it any gas,I scrambled to hit the off switch as fast as I can,and after I shut it down when Engine stops completely it sounds like something is still spinning inside.So I started again but this time taking video and it does the exact same thing again.So I don’t know what happened, if it’s developed a massive air leak somewhere, if I spun the crank bearing somehow,I don’t know.
If I grab clutch with both hands and try to wiggle it it is tight and doesn’t feel like anything is wrong.
I did a compression test and compression is still over 190.Fock!!!

Did you put the old spark plug back in? You only changed the plug and the coil so I would like one of them had to be the issue. If your in there changing out components it is also possible there was a lose connection somewhere? What did the new plug look like when you checked compression?

I didn’t even bother looking at plug when I took it out because that seemed the least of my worries at this point,and I had company coming over and needed to go hop in shower.The problems I have been having trying to get rid of that miss seem inconsequential to me now,to me now the big problem is the throttle going wide open on start up and that sound that sounds like something is still spinning inside when you shut the Engine off.
So no I did not stick the other plug back in,did not have a chance before it did it’s latest trick.
But I can tell you what plug looked like.The plug I took out(first plug) looked rich if anything.The plug I put in was a brand new plug I had previously done a plug chop with and it looked very gray,very lean looking.
So it was in buggy for about 3 -5 minutes of run time for these test before the run away throttle happening.I still have compression tester plugged in and plug was laying on roof and here’s the pics of it.To me it looks good just like you would want it to look.
Where you been curtis401?

I agree the plug looks good. I get it, least of your worries, and I can feel your frustration with this pilot. If you think its a leak check the obvious places around the intake and carb, make sure the plug is nice and snug, maybe something loosened up. Lets hope it is something simple.

You think the clutch screeching was from the new belt? Did you notice if it was much tighter it was than the old one? I would check that before proceeding.

I have been busy as f*uck. Trying to get on here now and again.

The belt didnt seem like it was tight,it went on easy enough.I would expect it to be tighter than the old one.I have no clue as to how much wear was on other belt,it was the spare that was strapped inside buggy when I bought it 4 or 5 years ago and it has been there since I took it off a couple weeks ago and put it on buggy

Yes, I would expect it to be a little bit tighter as well. Just strange the clutch starts making noises after a new belt is installed. I don't believe I read you had this issue previously.

That noise after it stops still has me scratching my head. If you turn it over without starting it is there still a noise?

Well now I am putting two and two together.
You have a high speed miss.
You have an Engine you can feather to full throttle with NO miss.
You have a run away ------- OHHHHHHHHHH ------- .
No way I would even start that thing again until you do a pressure/vacuum test.
In my opinion you got an air leak.
You may have other issues but I would start with the pressure/vacuum test as they are easy and will verify the condition of your seals and gaskets. Without a good sealed Engine you are wasting your time and possibly blowing an Engine soon. Everything else is secondary right now.
Just my opinions.
CO

Edit: Just went through this thread a bit, skipping a page or two at a time. This thing is being a girl machine. After you did the rebuild did you pressure/vacuum test this Engine ??

I have not messed with it after making video,it cranks up right away so I guess i could pull spark plug wire off and crank it over and see if it still made noise.It has been suggested to me to try to pull starting it and see if it still made that noise, but I have a slightly torn rotator cuff and I cannot pull start it, the compression is too high,I could not pull start it when healthy, it would rip the handle out of my hands.

Well It would seem I definitely have a big-time air leak now, either that or somehow my throttle cable got messed up somehow.
I did not vacuum test it because I do not have vacuum but I did pressure test it,it Has been suggested to me also that I might have put too much air in it when I did the pressure test, that 10 pounds was too much,but yes i did pressure test,it had very slow leak but i found a air leak in one of the fittings i used for test and I attributed the leak to it and considered the test successful

I have done 10psi several times with no detrimental effects so I don't count that. It's not recommended but you can get away with it. It's what I use sometimes but NO MORE than that.
As for the vacuum test -- it's not mandatory but if you have the tools like I do then go for it. If not then no big deal as I see it.
The question I have on your comment above is you said: " -- i did pressure test, it had very slow leak but i found a air leak in one of the fittings i used for test and I attributed the leak to it and considered the test successful"
You found an air leak in your test rig. Did you fix it and retest ??
The way I read it is that you didn't retest.
Also your comment that it had a very slow leak -- what does that mean exactly ??
You are not suppose to have any leak for at least 6 minutes and I won't put an Engine in if it don't hold the pressure for at least half hour before the air is gone.
CO

Yes you would be correct that I did not run another test.If I remember correctly it lost 2 or 3 lbs in 20 minutes.
Looks like I will be regretting that.Right now I'm pretty discouraged and tired of working on it.I will be out of town for next 2 weekends and wont be touching it for a while

Well the way I see this right now is that even though you did not do that retest, 2 or 3 lbs in 20 is not that bad really. I just needed to know what you meant by a successful test because you didn't specify any details. That would have still been marginal but it should have run fine. With that run away you just had I would say that something happened during your test runs. I would retest now to verify nothing went south on that Engine.
CO

Edit: By the way the best way I have found to killing a run away is to kill the ignition and FLOOR THE THROTTLE. I know this sounds wrong but it's not. When I first got into this oddy thing I had several run aways and this was a perfect solution. It's running away because of a lean out right ?? So give it fuel.
CO

Yes I’ve heard that before but I didn’t remember it when it happened,fortunately as soon as I turned the on off switch on steering wheel it cut off

So I was under my buggy tonight trying to find any clue as to why the throttle ran away like it did,And I see this giant hole underneath the pull starter which I don’t remember a hole being there before but it looks like it was made to be there.Even though I was pretty sure I couldn’t do it I tried to pull start the buggy and it ripped the cord right out of my hands but I heard something fall and I found this black piece on the ground that looks like it’s a perfect fit to go in that hole.Could that be the cause of my air leak to make the throttle go wild?

Here is an Engine I have sitting on the bench at the moment same notches as you have. Don’t see where they would contribute to an air leak. My guess is just a way for an moisture to drain out.

Yeah that's what I figured,very wishful thinking on my part.Do you know if that black plastic piece fits there or somewhere else?
thanks
Also took plug wire off plug so it wouldn't start and turned it over a couple times to see if it would make that spinning noise and it didnt do it,I didnt try to start it.But something else I just noticed,when I was turning it over I was staring at clutch and the clutch looked like it was wobbling,like the frickin shaft is bent wtf,what else is gonna go wrong.I left the key on yesterday so battery was dead tonight,I had it charging and I was messing with other stuff outside and I meant to go back to it and record some video and see if I was seeing things or is it really bent but I got tied up with what I was doing and forgot about it and now it's dark,I'll check it out tomorrow after work

That black piece I think came out of the end of the pull start handle.

Ha ok that would make sense