[Yendor]

That Idle circuit is controled by the Idle Mixutre srew.
The one that has the Washer and O-Ring on it.

I have seen 722A carbs where the O-Ring got smashed up and peices of it pushed back inside the carb where they are very difficult to extract them from.
Use Carb CLeaner with the Spray tube to be sure your passages are clear and the psray comes out where expected.

 

[barab63]

Yendor

Thank you. For bowl gasket: Gasgacinch? It is a bit "longer" than I recall during install this year.

 

[barab63]

Went ahead and used a tiny amount of gasgacinch on the carb diaphragm to seal it and the bowl gasket to hold it in place. I was very careful to wipe off any excess.

Trying to diagnose the erratic idle with Sprint66 on the phone, we worked our way backwards, stopping at the points advancer bolt and washer, which turned out to be the wrong ones. This picture shows the correct bolt.

The correct bolt and washer are hardened steel. This pic shows how concave the wrong washer became. It started out flat.

When the engine was running, I noticed that the fuel consumption seemed excessive. The gas is being gravity fed from a 2000 mL plastic aux fuel bottle. In the 10 or 15 minutes that the engine was running, it consumed about 600 mL.

I pulled the plugs, which were new at the start of the day. The pic below shows what they look like.

The fuel/air mixture screws were set between 3/4 and 1 full turn out at the start, but the plugs look like the mixture was too rich?.

 

[barab63]

If too rich, what are possible causes?

 

[66Sprint]

Air cleaners clogged?...... Try running without them installed for a bit/use new plugs....... Old paper elements tend to get matted and not flow well......

Liquid level in carbs too high/float level set too LOW.......Try 1 mm higher to 1.5mm higher than spec.....Which varies by carb type.....
Specs are: 350-A @19 mm,... 3-C @ 21 mm,...3-D @ 26 mm

 

[nyweb]

I got my CM400E from a guy who said he NEVER shuts off the gas. My overflow tubes were constantly dripping. I started shutting the gas off and it cleared up after a week or so. I'm bad at shutting off the gas also. I put a little label right buy the key........."GAS" !!

 

[barab63]

Air cleaners clogged?...... Try running without them installed for a bit/use new plugs....... Old paper elements tend to get matted and not flow well......

Liquid level in carbs too high/float level set too LOW.......Try 1 mm higher to 1.5mm higher than spec.....Which varies by carb type.....
Specs are: 350-A @19 mm,... 3-C @ 21 mm,...3-D @ 26 mm

Floats are set to 26 mm. Replaced old OEM filter elements with new OEM yesterday. New plugs are installed, gapped to .031". I have a new advancer unit bolt, just waiting for an advancer unit washer to arrive. Thanks for your feedback.

 

[barab63]

Floats are set to 26 mm. Replaced old OEM filter elements with new OEM yesterday. New plugs are installed, gapped to .031". I have a new advancer unit bolt, just waiting for an advancer unit o-ring to arrive. Thanks for your feedback.

I believe one of the possible reasons the idle might hang (in this case at about 3K rpm) is if the advance plate springs are stretched. Looking at the attached pic, can anyone tell me if these springs "look" worn. They are each about 10 mm at rest, and they are taught when mounted between the peg and the hole in the weight. If they are stretched too much, how many coils should be removed?

 

[barab63]

Anyone have any insight of this issue?

 

[66Sprint]

Lots....too much to type to explain....Phone me.......

 

[barab63]

Will do.

 

[barab63]

Steve, Based on the following post on 8/8/19 about the correct arrangement of the points connection.....Bolt (head) metal flat washer, insulating washer, base, insulating washer, SPRING, point wire ring, flat washer, lock washer, nut....... it looks like mine are not assembled correctly? See pic

 

[66Sprint]

You are fine......That was describing the bolt head inside.....Yours are outside....either way works as long as separated from points base by insulating washers.....

 

[barab63]

Got it. Thank you. I'll let you know when I get the new points set.