Onan 4.0 CCK-3CR shutting down after running a few minutes

[John Ward]

Well my little CCK started acting-up a few days ago and was shutting down after a few minutes of running. It would start right up but not run long, and would start right back up but continue this scenario. I checked and re-gaped the points, checked the recently installed wires, was getting good fuel, but still the same issue. I was considering changing the points and condenser but something kept saying 300C859 board. So I pulled the board, cleaned it with contact cleaner but still same issue. Then I inspected the solder joints under a good magnifier and sure enough there were some cracked solder joints.

I cleaned what I guess was some type of varnish off the solder joints and re-soldered them. I re-inspected and it seemed ok. Then went back to the genset for a re-install and start-up. Well it started right up with only a couple revolutions and ran smooth. I let it run for approx. 20 minutes and it just kept going until I shut it down. I will give it more run time tomorrow after I cut the grass, spread weed & feed, and put down 20 bags of pelletized lime. A new board from Flight Systems is $150.00 and I have not checked on the cost to convert it to relays but if this does not last I might go that route if it is cheaper than a new modern board. The Flight System board has a two year warranty and looks like a vastly improved design.

A 1975 CCK sounds better than a brand new 3600 rpm screamer. I would like to know the hours because it runs like it was just made, a real work of craftsmanship.

[Billy J Shafer]

Cracked solder joints. Was one of many problems with the 859 board. Got so bad Onan came out with a relay upgrade. I don't think kits are available anymore from anybody. But you can build your own. Parts are just common parts. I can send you a print.

Flight System boards are very well built. I have used them for years. Never had a problem.

[MBB]

John the parts rrequired for a conversion will be $25.00 at most. The relays are common auto relays. I have a 5.0cck with the conversion. Much simpler setup and if a part goes bad its simple to replace. Take Billy up on his offer for a wiring diagram if not I have one or there is one in the service manual. I believe its 611-1127 if Im not mistaken.

[John Ward]

Thanks guys, I would rather have a relay system instead of relying on a circuit board. I would really appreciate a diagram and a list of parts needed. Being an HVAC tech I can buy the parts wholesale so getting them is no issue. I am guessing I will also need to install resistors? Also if anyone has the 611-1127 manual I would appreciate it.

jwward2@gmail.com

[Billy J Shafer]

This is the print for the relay for the RV units. Without start disconnect board.

[John Ward]

Originally Posted by MBB

John the parts rrequired for a conversion will be $25.00 at most. The relays are common auto relays. I have a 5.0cck with the conversion. Much simpler setup and if a part goes bad its simple to replace. Take Billy up on his offer for a wiring diagram if not I have one or there is one in the service manual. I believe its 611-1127 if Im not mistaken.

Hello,
Would you happen to have specs on the capacitor and rectifier needed for this conversion?

[MBB]

John just found your post. I can dig up the part number I believe. Im not sure what capacitor your referring to. I know the diode is available others have replaced those. I have information on it ill look and see if I can find it.

[John Ward]

Well I have been running the CCK for twenty to forty-five minutes at a time and she runs smooth as silk. Thirty-seven years old and she just purrs.