guy10596 wrote:I have 135 on all cylinders at this time but it only has maybe 1 hour on the motor after sitting for 19 years , I have been able to isolate the problem to the #4 carb i dont have any adjustment on the mixture on this carb so plans are to remove them and clean the mixture passage again
seabee_ wrote:I believe 'one' carb does not have adjuments, which is why the other 3 carbs are synced to the one carb. Correct me if I'm wrong?
seabee_ wrote:Yeah, I wasn't sure so I pulled the ole manual out. Found the sync section and read a "Note: The #4 carb cannot be adjusted. It is the base." That's as per the '84 service manual. Don't know if the 1100 is any different.
virgilmobile wrote:OK . I'm assuming that the idle mixture,when run from a snug seat to 3 turns open has no affect on the way the engine runs.True?
I also assume that that cylinder actually does run.Verified by a "pull the plug" test or checking the temp of the header.True?
After all that then the only thing left is that one idle jet pathway is plugged in the carb.Either the idle jet itself or the ports.
To avoid any confusion of which "adjustment" were talking about,can you add a pix pointing to it?
You know,it's the potatoe potaaaatoe thing..
virgilmobile wrote:I've done my 1000,1100 and 1200. They all have 3 screws to adjust the 3 carbs for syncing.One between the right set and 1 each toward the rear of each on the left set.all 4 had idle mix screws under the bowl.
seabee_ wrote:When you rebuilt the carbs, did the o-ring come out with the mixture screw? Or did any of it get stuck down in the hole? What about the needle on the end of the mixture screw? Is it all there or did a part of that break off in the hole? It is sounding like a fuel flow problem. Or are you talking about the mixture screw itself not adjusting/moving?
virgilmobile wrote:Ok,I see the mix on the 75 is in a better location than my 78.makes me wonder now?Anyways,if the mix dosen't make a difference even when bottomed out(closing off the fuel for idle)then the cylinder must be getting fuel from somewhere else.Now IF the butterfly is open too far It will negate the operation of the mix adjustment and move to the feed holes just under the butterfly lip.Is it possible the butterfly is stuck open a bit?Can you adjust the "sync"screw down and kill that cylinder?
virgilmobile wrote:I'm at a loss here on this one.A prefect sync and the idle mix has no idle down affect...Hmmm
I'm struggling with how the cylinder gets fuel at a idle with a inoperative idle mix screw.It should near kill the cylinder when the mix screw is bottomed out,effectivly cutting it's fuel supply.Perhaps it isn't,and the mixture screw tip isn't going into the hole.Don't know.
I'd be jetting some water with a water pick through the idle circuit to find out and compare the results with the next carb.
Sorry...I was just typing aloud..
Fred Camper wrote:I gotta believe that number 4 mixture screw is not able to stop the flow of fuel. So you guys seem like you are on the right track. I see no other alternative now that the carbs are in sync.
virgilmobile wrote:I mastered the points on my 78.
Split timing (splitting the difference)......Here's the idea.
Set the gap midrange for the first point and move the baseplate to time it.
Set the gap to time the second points.The baseplate is no longer movable so to time the second set you adjust the gap.This is by the book.
Fine...I just add one more step.
When it's done,measure the gap on the first set,lets say it's 0.016"
Measure the gap on the second set.I'll bet 4 cents it won't be the same....So with it's measurement,say it's 0.012"...you would split the difference....
This means you would re-adjust the gap on the first set to 0.014" and re-time.
Re-time the second set and check it again.
The idea is to get not only the timing correct but to get the points to open the same ammount(dwell angle).
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