83 Excel III Won`t Idle

L

lilnotts

New member
Joined
Jan 25, 2011
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Age
38
Location
Sarnia, ON
I`m working on an 83 excel III 340 and I have just rebuilt the motor and cleaned out the carb. The carb was really dirty and everything was quite stiff. I`ve soaked the entire carb twice in carb cleaner and I have sprayed carb cleaner through what I think is every passage and they all seem clean. When I start it will run with the choke on half way and it will idle but at about 2000rpm. I can rev it up while the choke is on. It will not stay running if I turn the choke off. The jets are clear, the screw is at about 1 turn out. It does not seem to make a difference if the airbox is on or not. I`m kind of running out of ideas.
 
I've taken the carb apart and checked all of the passages again one passage doesn't seem to go anywhere.I've attached a pic, anyone know where its goes? The pilot passage is clear and a new jet has been installed(as I slightly damaged the slot on the old one). Also, I am not sure if my coils are set up right. The manual states "Align the pry points on the plate with the cut out on the crankcase", I think thats how I have it.
 

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I expect you did the crank seals ????
Once apon a time , I owned a 73 eltigre 440 and it would idle
perfect but to go any faster you had to hold it wide open and
choke it ....made an interesting launch....
It turned out the last owner had lost the bowl drain screws
and installed some that were too long....they reached up and
sealed off the main jets...LOL
It sure sounds like the main circuit is clogged...I see alot of
rust ...did you remove the main and pull out the core above it ??
Calcium and rust can close off all the fine holes.
I don't have a book on your carb, but expect it will have the core
and you would need a small sliding hammer to pull it...Ask a Mik
expert about it...
Ron
 
crank seals have been replaced, I have removed the main jet but not the core above it as I can not get it out. I have however blown compressed air through it. It is interested that you think the main circuit it clogged as I would have though it would be the pilot/air screw passages that would have the issue. I had assumed the main circuit must be ok since if I have it half throttle or more it will run without choke. I seem to have the opposite issue to the eltigre you had.
 
sounds like the carb boot is not sealing properly. our 78 et340 had this and crank seals at the same time.
 
I have the screw at 3 and 1/2 turns out on my 83 Excel 3. If the butterfly on that carb looks like that, I would imagine you may need some internals replaced.
 
Thunder101 said:
take your pilot jet out and have a look at it. best is throw the butterfly in the bush. M2C
Click to expand...

One of the simplest carbs ever and yet some can't handle them.

Jeeze......

lilinotts,,

That carb passage you have the arrow pointing to should be open to the main fuel tube directly behind it. If it's plugged it won't run right. The air passages in all carbs are just as if not more important than the fuel passages. They must be clean too. Probably why guys like thunder want to toss them all the time.

opsled
 
Yes, that is your main air jet. In order to pull fuel through the main, air needs to pass through there.

A simple rule when I clean carbs is to know where each circuit goes and make sure it is open and not clogged. I simply watch where the carb cleaner goes. Some circuits have more than one opening so it is important to know the whole circuit. They are really simple and easy once you see them explained.
 
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