Spica Idle and Cold Start issues
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OK got out there this late afternoon and just wrapped up.
Short story - its fixed, idles nicely at 600, maybe 650 rpm. The short link was set too long even after multiple attempts to set it.
Long story:
-Removed FCS, cleaned it by soaking business end in solvent, repeated 2X, flushed solvent squirted oil on it & reinstalled. Verified it works, but no love, no change.
- Checked that each plug was firing, cap and rotor (they look new), wires seem fine, all electrical connections tight.
- I eventually noticed that holding my thumb over the idle port/adjuster did little as I tried to approach an idle speed. I had set the short link per instruction again just today, but apparently the throttles were not quite closed (maybe the bores are a bit worn from throttle plates digging into them?). For me, the soft/hard close approach didn't do it.
So, yeah, I was way lean at idle, hence stalling/sputtering. I simply adjusted the short link until my thumb told me the throttles were closed. I figured this would sync the throttles with the pump. And bingo, it suddenly idled nicely.
The FCS seems to work really well now, maybe cleaning helped or maybe I'm rationalizing the time I killed cleaning it.......
- My ancient dwell tach says idle is a pretty even 600, but I think it reads 50 rpm low (I compared to another some time back). Either way, I'd prefer 7 to 800 rpm. But I still need to set mixture (and CSS) and make sure all is right, so maybe I'll gain a 100 rpm at the end of it. The idle o-ring is fine also, plenty soft and not squished. Don't know if the idle tower has the update (basically a larger hole), not sure if that helps idle.
-I'll see what else I learn here and update.
Thanks for all the help.
Short story - its fixed, idles nicely at 600, maybe 650 rpm. The short link was set too long even after multiple attempts to set it.
Long story:
-Removed FCS, cleaned it by soaking business end in solvent, repeated 2X, flushed solvent squirted oil on it & reinstalled. Verified it works, but no love, no change.
- Checked that each plug was firing, cap and rotor (they look new), wires seem fine, all electrical connections tight.
- I eventually noticed that holding my thumb over the idle port/adjuster did little as I tried to approach an idle speed. I had set the short link per instruction again just today, but apparently the throttles were not quite closed (maybe the bores are a bit worn from throttle plates digging into them?). For me, the soft/hard close approach didn't do it.
So, yeah, I was way lean at idle, hence stalling/sputtering. I simply adjusted the short link until my thumb told me the throttles were closed. I figured this would sync the throttles with the pump. And bingo, it suddenly idled nicely.
The FCS seems to work really well now, maybe cleaning helped or maybe I'm rationalizing the time I killed cleaning it.......
- My ancient dwell tach says idle is a pretty even 600, but I think it reads 50 rpm low (I compared to another some time back). Either way, I'd prefer 7 to 800 rpm. But I still need to set mixture (and CSS) and make sure all is right, so maybe I'll gain a 100 rpm at the end of it. The idle o-ring is fine also, plenty soft and not squished. Don't know if the idle tower has the update (basically a larger hole), not sure if that helps idle.
-I'll see what else I learn here and update.
Thanks for all the help.
Joined
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2,552 Posts
Nice. If you have the plastic rod ends on the two throttle rods still, have a real close look at them. The can crack, the round part that snaps over the ball and also where the threads are. If it’s cracked where the threads are the ball end can slide on the threads and you loose your previous adjustment.
Yeah, although the rods ends are reasonably fresh, I pushed them off and on so many times I think I'll order a set to have just in case. At the moment, they are OK. Still a bit more work to do, but at least she runs. Thanks for the input
So today I checked some things mostly to make sure I had everything tight and where it needed to be and to check for sockets/tools, etc. in the engine bay before starting/test driving it.
Before starting I richened the CSS by a half turn. This must have helped as it lit on 3 hits of the starter instead of 6 or 7. Did not get a fast idle, but it idled right away and took throttle after a minute or so.
Test drive says mixture is pretty close as it pulls smoothly and easily to 5500. Previously it sounded strained above 4000. Power is great all thru the range, revs like it should. Set up per the procedure makes all the difference..
No backfiring or other nonsense during driving and it always returned to idle without any of the, is it gonna idle or stall out drama that I was more or less used to.
Idle was good, maybe a bit lean, I can tighten the idle adjuster and squeeze the o-ring a bit and see if it helps. Or maybe mixture needsto be a tick richer. Will drive it some more and see how plugs look. Either way, I'm very close to where it needs to be.
Thanks again.
Before starting I richened the CSS by a half turn. This must have helped as it lit on 3 hits of the starter instead of 6 or 7. Did not get a fast idle, but it idled right away and took throttle after a minute or so.
Test drive says mixture is pretty close as it pulls smoothly and easily to 5500. Previously it sounded strained above 4000. Power is great all thru the range, revs like it should. Set up per the procedure makes all the difference..
No backfiring or other nonsense during driving and it always returned to idle without any of the, is it gonna idle or stall out drama that I was more or less used to.
Idle was good, maybe a bit lean, I can tighten the idle adjuster and squeeze the o-ring a bit and see if it helps. Or maybe mixture needsto be a tick richer. Will drive it some more and see how plugs look. Either way, I'm very close to where it needs to be.
Thanks again.
Joined
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12,170 Posts
A maybe helpful test…
I gave/loaned my 77 S2 to my nephew last year, so he’s nice enough to let me use it while I’m in the states for the recently past holiday of gluttony.
I had brought the car a lonnng way back from its 20 years of garage-storage by PO, but not everything was perfect when I shipped it to Houston. The idle would typically stick at about 1,100-1,200.
So today, I had a sudden idea…
While halted at a stop light on Voss Rd, I held the brake while slowly letting out the clutch in 1st gear. The idle came down to 700, clutch in, idle stayed at 700.
Repeated many times, same thing.
I reckon this is a good test to determine if gunk in the dizzy is conspiring with weak springs to keep the timing advance slightly elevated. Once rotation has slowed, the springs finish retracting the weights.
My nephew, as a mechanic, is a good carpenter. I’ll figure out how to remotely get this investigated.
I gave/loaned my 77 S2 to my nephew last year, so he’s nice enough to let me use it while I’m in the states for the recently past holiday of gluttony.
I had brought the car a lonnng way back from its 20 years of garage-storage by PO, but not everything was perfect when I shipped it to Houston. The idle would typically stick at about 1,100-1,200.
So today, I had a sudden idea…
While halted at a stop light on Voss Rd, I held the brake while slowly letting out the clutch in 1st gear. The idle came down to 700, clutch in, idle stayed at 700.
Repeated many times, same thing.
I reckon this is a good test to determine if gunk in the dizzy is conspiring with weak springs to keep the timing advance slightly elevated. Once rotation has slowed, the springs finish retracting the weights.
My nephew, as a mechanic, is a good carpenter. I’ll figure out how to remotely get this investigated.
At one point I was thinking I might have to remove the pump, but for now all seems well. Good to have some luck once in a while.
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