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Discussion Starter #1
I was just wondering if anyone knows what causes a engine to not idle properly. When I first start it up it does not want to idle. It stalls out. It only seems to idle when it's fairly cold. Do I need to do some carb adjustments?
 

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if it idles well when it is cold outside vs warm outside i would think it is too rich . could be quite a few different things . how does it run above idle?maybe your choke cables are not set right (when off they should have some free play as in up and down movement at the carb) has it alaways done this? if so maybe someone screwed with the pilot jet or idle air screw.(1.5 turns out from lightly seated is a starting point ) the carbs could be out of synch.you can set them up close with a drill bit under the slide and adjust the cables untill the slides just hit the drill bit then adjust idle. (take the belt off when doing this to prevent sudden take off in case the idle is too high when you start it).possibly the float level is too high. poor plugs? kep us posted:cool:
 

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Discussion Starter #3
It might be running too rich. I have not checked my plugs yet since I have changed my silencer. What size of drill bit should I use to syncronize the carbs? The plugs are new and as are the wires. I took it for a run last night (-35) and it was idling good at about 1200 rpm. When it's warmer it won't idle without holding the throttle. If I have to make any jetting changes from my silencer what do I change them to? Thanks for any info.
 

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any size drill bit will work. you just want the slide to come down and touch the bit as it lays in the carb . try a 3/8 i guess.
the silencer shouldnt affect idle at all more wot and it may require a slightly larger mj . it depends how close your jetting was prior to the switch
 

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Discussion Starter #5
I took the carbs out last night and did a bit of syncronizing. The carb boots were full of gas and so were the carbs. It seemed to be flooding out. The carbs were out quite a bit. I eventually got it to idle very smooth at 1500rpm. What a big difference that a bit of carb tuning can do. The enging seemed to be running good. It was not running rich. Thanks for the help 100mL.
 

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Discussion Starter #6
I have got engine to idle pretty good but now I have a small bog at about 1/4 throttle. Is it the low speed setting that needs to be adjusted?
 

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glad to hear you got her fixed , almost. your pilot jet controls mostly idle and a small amount all the way to wot (5-10%) if it is idling good pilot is good.next is your throttle valve or slide it controls mostly off idle in the 1/8 range leave it alone, next is your needle jet ,the brass tube that the main jet screws into and the needle slides up and down in. this controls from just under 1/4 ,mostly just above 1/4 and tapers out to just after 1/2 throttle. this could be your problem .but lets wait. next is your needle this controls from 1/4 to just over 3/4 but mostly just above 1/2. last is your main jet.
i would try dropping the clip 1 position on the needle .this will richen it up. see if that helps if not go 1 above your starting point and try again if this gets better be aware that you have just leaned out your top end as well slightly so make sure you check your plugs and piston was often.
i have heard a lot of people saying there is a flat spot on these engines but i have never worked on one to see why
 

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Discussion Starter #8
Yes I have heard quite a bit that these engines have a flat spot as well. I am back to having the idling problems again. Some times it works fine and idles perfectly and other times it won't idle at all. Getting fustrated!!
 

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You mentioned earlier about gas in the carb boot. I thought then float valve. Clean the carb, maybe replace the float needle. But I more think you have some crud in there than a bad needle because it's intermittant.
If it ran well sometime in the past with the clips in the original position and jetting, then it shoud run again well at the same settings.

When removing carbs I like to preserve the gas in the carb bowl and dump into a clean tray. Sometimes interesting things appear..like a bubble of water or bit of crud especialy rust or someting that did not originate in the carb.
Did this problem appear after comeing out of storage? Was Stabil used? Isopropyl based drygas ocaaisionaly?
Hope this helps. Keep us posted.
 
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