Starting Problem AC-720 Onan CCKB

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I have a 19.5 hp ONAN CCKB engine on my Simplicity 4040 that came out of an AC-720.  It will not start if throttle is not fully retarded (at the carb).  It is hard to start and will die if given too much throttle.  In fact, on starting the throttle must be fully retarded and only advanced very slowly until the engine is warmed up to operating speed.  It cranks easily, but cranks forever before finally hitting and running (at a very low RPM).  Once up to operating temperature, it works normally - throttle can be set to idle & then advanced to full without any problem.

I've checked the coil, points, timing, fuel pump, and cleaned/adjusted the carb.  Air cleaner is good.  Seems to be a governor issue and I know absolutely nothing about ONAN governors.

Any suggestions would be appreciated.

Edited by Chief Cockeye - 21 Jan 2016 at 11:11am

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Chief Cockeye Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 13 Jan 2016 Location: Auburn, KS Points: 12	Post Options Post Reply Quote Chief Cockeye Report Post Thanks(0) Quote Reply Topic: Starting Problem AC-720 Onan CCKB Posted: 21 Jan 2016 at 11:09am
	I have a 19.5 hp ONAN CCKB engine on my Simplicity 4040 that came out of an AC-720. It will not start if throttle is not fully retarded (at the carb). It is hard to start and will die if given too much throttle. In fact, on starting the throttle must be fully retarded and only advanced very slowly until the engine is warmed up to operating speed. It cranks easily, but cranks forever before finally hitting and running (at a very low RPM). Once up to operating temperature, it works normally - throttle can be set to idle & then advanced to full without any problem. I've checked the coil, points, timing, fuel pump, and cleaned/adjusted the carb. Air cleaner is good. Seems to be a governor issue and I know absolutely nothing about ONAN governors. Any suggestions would be appreciated. Edited by Chief Cockeye - 21 Jan 2016 at 11:11am

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Steve in NJ Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Andover, NJ Points: 11586	Post Options Post Reply Quote Steve in NJ Report Post Thanks(0) Quote Reply Posted: 22 Jan 2016 at 6:13am
	Is the choke working? And here's the reason why I ask. Sounds like its a cold start choke problem. My neighbor had the same similar problem with his Bolens rider. Hard starting when cold, (worst in the Winter) and then once it started warming up the throttle response was normal. He asked me if I would check it out for him and I did. What I found was when you pulled the choke on, the cable stop screw loosened up from vibration, and when you pulled the choke, the choke wire was pulling through the cable stop block so the choke wasn't working. Trying to start a air cooled engine even in the summer with no choke sometimes can be a bear depending on the engine. I adjusted the cable again, tightened the screw down so the choke would operate again and he was good ta' go. Somethin' as dumb as that can make ya crazy sometimes... LOL! Who would've thought? Sometimes the fix can be easy.. Steve@B&B
	39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife

Chief Cockeye Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 13 Jan 2016 Location: Auburn, KS Points: 12	Post Options Post Reply Quote Chief Cockeye Report Post Thanks(0) Quote Reply Posted: 22 Jan 2016 at 7:12am
	Thanks, Steve, I will check out your theory about the choke later today. You description of your friend's motor sounds very similar to what I'm experiencing with mine. I'll try to let you know what I found later today. Thanks, again.

Chief Cockeye Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 13 Jan 2016 Location: Auburn, KS Points: 12	Post Options Post Reply Quote Chief Cockeye Report Post Thanks(0) Quote Reply Posted: 22 Jan 2016 at 7:38pm
	BINGO! You're da man, Steve in NJ! Sure enough, the clamp that is SUPPOSED to hold the cable was not tight enough and allows the cable to slip. When I thought I was choking the engine, I wasn't doing anything. It was about 20°F this morning & with about 1/2 choke she cranked right up. Thanks. If you're ever out this way I owe you a cup of hot coffee - or what ever you drink.

macvette Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 13 Jun 2011 Location: nekoosa, wi Points: 1656	Post Options Post Reply Quote macvette Report Post Thanks(0) Quote Reply Posted: 23 Jan 2016 at 3:09pm
	Yep, same thing happened to me this year when weather turned cold. Was checking gas, point gap, everything I could think of, etc. Couldn't figure out why, finally stood along side with hood up, pushed choke to off, was going to try again, and saw choke cable moving. Tightened cable down where it was supposed to be, and engine started as it should. I really feel better now that I know it has happened to someone else! (was feeling quite foolish that I didn't immediately spot it.)

Chief Cockeye Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 13 Jan 2016 Location: Auburn, KS Points: 12	Post Options Post Reply Quote Chief Cockeye Report Post Thanks(0) Quote Reply Posted: 23 Jan 2016 at 4:29pm
	Yep. I know the feeling.

Steve in NJ Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Andover, NJ Points: 11586	Post Options Post Reply Quote Steve in NJ Report Post Thanks(0) Quote Reply Posted: 25 Jan 2016 at 6:22am
	Glad to hear that fixed your problem Chief! Like I said, sometimes the stupiest things make you tear your hair out. Ya know, when ya think about it, we take so much for granted that ya think everthing is working the way its supposed to so you just don't think to check it I guess. We're all human. I'm just a much a victim of it as anyone else... LOL! Oh BTW, I'm a tea drinker. I don't drink coffee. But thank you for the offer! LOL! Steve@B&B Edited by Steve in NJ - 25 Jan 2016 at 6:25am
	39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife