Topics

Running on Three Cylinders

seb fontana
 

As the title states my 47 CC is running on three cylinders..This happened while going down the road at 40 mph, no hint at anything being wrong prior..No pinging, no over heating, no extra noise..Cyl #4 Just stopped running..Plenty of spark; the plug looked fine but replaced it and still no fire.Valve clearance is at spec of .004/.006.Checked compression and found #30 lbs, all others are at #120..Put air adapter in spark plug hole and hooked air supply up and air was exiting the exhaust pipe..So bad exh valve or seat..Am I missing some thing? There was no clue to something being wrong; I didn't think a valve could go bad in an instant..Any input? 

Barry Smedley
 

Did you check and see if the spring is broke.

 

   Barry Smedley

 

From: Crosley-Gang@groups.io [mailto:Crosley-Gang@groups.io] On Behalf Of seb fontana via Groups.Io
Sent: Thursday, October 31, 2019 8:31 PM
To: Crosley-Gang@groups.io
Subject: [Crosley-Gang] Running on Three Cylinders

 

As the title states my 47 CC is running on three cylinders..This happened while going down the road at 40 mph, no hint at anything being wrong prior..No pinging, no over heating, no extra noise..Cyl #4 Just stopped running..Plenty of spark; the plug looked fine but replaced it and still no fire.Valve clearance is at spec of .004/.006.Checked compression and found #30 lbs, all others are at #120..Put air adapter in spark plug hole and hooked air supply up and air was exiting the exhaust pipe..So bad exh valve or seat..Am I missing some thing? There was no clue to something being wrong; I didn't think a valve could go bad in an instant..Any input? 

This message contains confidential information intended solely for the use of the addressee(s) named above. Any review, disclosure, distribution, copying or use of the information by others is strictly prohibited. If you have received this message in error, please advise the sender by immediate reply and delete the original message. (English) Ce message contient des informations confidentielles destinées uniquement à l'usage du(des) destinataire(s) nommé(s) ci-dessus. Toute consultation, distribution, copie et utilisation du contenu de ce message est strictement prohibée. Si vous avez reçu ce message par erreur, SVP avisez l'expéditeur par réponse immédiate et effacez le message original. (French)

Butch
 

Seb,

Although I doubt that the spring broke (this would have shown up when checking clearances), it's quite possible that some carbon has dislodged and caught between the valve and the seat.

With the cam cover off, the follower located at the center of the cam base circle (lobe pointed straight up), take a hammer and a punch (preferably a soft punch, even a hardwood dowel) and smack it forcefully, several times.

If this can be done, with the air hose attached to the spark plug hole, it will be more effective.

Exhaust valves and seats, do burn occasionally, but not real often on Crosleys, and it's not an all at once thing. The exhaust valves were made of good material. Numbers on and four, exhaust seats, are prone to recession and burning, due to poor coolant circulation and cooling.

I hope that this helps, it's my best long distance, diagnosis for now.

Butch

On 11/1/2019 6:32 AM, Barry Smedley wrote:

Did you check and see if the spring is broke.

??

???? Barry Smedley

??

From: Crosley-Gang@groups.io [mailto:Crosley-Gang@groups.io] On Behalf Of seb fontana via Groups.Io
Sent: Thursday, October 31, 2019 8:31 PM
To: Crosley-Gang@groups.io
Subject: [Crosley-Gang] Running on Three Cylinders

??

As the title states my 47 CC is running on three cylinders..This happened while going down the road at 40 mph, no hint at anything being wrong prior..No pinging, no over heating, no extra noise..Cyl #4 Just stopped running..Plenty of spark; the plug looked fine but replaced it and still no fire.Valve clearance is at spec of .004/.006.Checked compression and found #30 lbs, all others are at #120..Put air adapter in spark plug hole and hooked air supply up and air was exiting the exhaust pipe..So bad exh valve or seat..Am I missing some thing? There was no clue to something being wrong; I didn't think a valve could go bad in an instant..Any input???



Virus-free. www.avast.com