Post by henrypaz on Sept 18, 2023 16:11:41 GMT -5
Well Justy Friends,
I just got back from Justy Hell again ( removing and installing the Hitachi carb. ) If you haven't tried it, I highly recommend it as a character building exercise. Lots of opportunities to practice not cursing and such, when you drop those little parts down into that dark bottomless pit of the Justy's bowels. Or trying to get those back nuts on. ( You can't even SEE one of the studs it goes on !! And unless you're double jointed you can barley touch it either.) Don't take this as complaining. I love my Justy and think She's worth it. I'm just sayin'......
Anyway, I managed to get the carb apart and back together and installed and solved my original problem ( It initially wouldn't idle at all. Could have been the CFC solenoid. I never found out anything. Just cleaned it out and put back together. )
So now it starts easily without pumping or throttle and idles like a dream.
BUT--at 3500RPM it begins to shake back and forth very regularly, not erratically. Repeatable on every throttle opening. Just keeps rocking back and forth quickly as long as I hold the throttle open. My best estimation of the speed of that rocking back and forth is about 240 times per minute? Four times per second. If I go up in RPM, say 4000, she just keeps shakin', at the same frequency, not faster.
When I test drive her, she's got a flat spot, delayed response as well. Not running well.
I've checked my timing, set my idle speed ( the mixture screw doesn't make much if any difference.) It idles very nicely. Checked all my vacuum hose cnxns. good there. I cleaned and tested the EGR system. Ran it disconnected as well. No difference. I did tinker with the 'fast idle screw', and the 'throttle adjustment screw', but no other physical adjustments.
I'm sorta stymied. maybe someone out there has had something similar, and can give some advice? I sure can use some help. Thanks to anyone with an idea.
I just got back from Justy Hell again ( removing and installing the Hitachi carb. ) If you haven't tried it, I highly recommend it as a character building exercise. Lots of opportunities to practice not cursing and such, when you drop those little parts down into that dark bottomless pit of the Justy's bowels. Or trying to get those back nuts on. ( You can't even SEE one of the studs it goes on !! And unless you're double jointed you can barley touch it either.) Don't take this as complaining. I love my Justy and think She's worth it. I'm just sayin'......
Anyway, I managed to get the carb apart and back together and installed and solved my original problem ( It initially wouldn't idle at all. Could have been the CFC solenoid. I never found out anything. Just cleaned it out and put back together. )
So now it starts easily without pumping or throttle and idles like a dream.
BUT--at 3500RPM it begins to shake back and forth very regularly, not erratically. Repeatable on every throttle opening. Just keeps rocking back and forth quickly as long as I hold the throttle open. My best estimation of the speed of that rocking back and forth is about 240 times per minute? Four times per second. If I go up in RPM, say 4000, she just keeps shakin', at the same frequency, not faster.
When I test drive her, she's got a flat spot, delayed response as well. Not running well.
I've checked my timing, set my idle speed ( the mixture screw doesn't make much if any difference.) It idles very nicely. Checked all my vacuum hose cnxns. good there. I cleaned and tested the EGR system. Ran it disconnected as well. No difference. I did tinker with the 'fast idle screw', and the 'throttle adjustment screw', but no other physical adjustments.
I'm sorta stymied. maybe someone out there has had something similar, and can give some advice? I sure can use some help. Thanks to anyone with an idea.