Re: Rough Idle/Backfire

Sat Jun 29, 2013 11:36 am

Yeah its been relatively low on power since I resurrected it. I looked at the spark plug wires today and THEY WERE WRONG. Not sure how that happened but I placed the wires in order (on the cap it is top right where labeled "1" I placed to the most forward spark plug and followed the "1-3-4-2" firing order while going clockwise around the distributer cap. I got excited, went to crank it over and its fighting itself... SO, I guess I am going to start from scratch with the timing which is a PITA to me because I struggled with it the first time. I dont have a timing light :/

Re: Rough Idle/Backfire

Sun Jun 30, 2013 3:59 pm

Okay the Cub is back in action and running really well. I did the timing procedure probably 15 times. Apparently when I was at 1 o'clock in the distributer, I should have been at 7. So I was around 180 out all day. Anyway, it runs really well in all gears and doesnt bog down with the PTO or hydraulics anymore. For some reason, the exhaust is significantly quieter and has a reserved tone whereas before it was clearly louder, aggressive and mean. Does anybody know why this is? Also, the smoke has returned :?

Here's an updated vid: ... ata_player

Re: Rough Idle/Backfire

Sun Jun 30, 2013 8:57 pm

Cranked on full throttle and let it run for about 5 minutes successfully until it started bogging down and began to backfire through the exhaust (small carbon clouds flew from the muffler) where it then continued to bog until it died. Now it cranks like before and no start.

Any chance that the muffler is stopping up with rust flakes etc.?

Re: Rough Idle/Backfire

Sun Jun 30, 2013 9:31 pm

The muffler is pretty gummed up with carbon soot but I've banged and flushed most of it out. I was considering a classic chrome straight pipe that the larger rigs have but theres no point to sacrifice the stock look when the aggressive sound is no longer there.

Re: Rough Idle/Backfire

Tue Jul 02, 2013 4:03 pm

So I figured out why the exhaust was louder, more aggressive and burning insanely hot before I corrected my timing. Apparently since combustion was happening late in the cycle, the characteristics of combustion are carried beyond the valves and into the manifold, exhaust pipe and out. Because the pressure of the combustion wasn't contained, I had a severe decrease in power. Too bad because even though I had low power, the Cub sounded amazing and burned off the smoke with the high EGTs.

Re: Rough Idle/Backfire

Wed Jul 03, 2013 12:16 pm

AgTires4295 wrote: So I was around 180 out all day.

The timing being 180 out will certainly make for low power and other mysterious headaches (running hot, excess fuel consumption ...)
I watched both videos and in the second one, well, it just sounds like a happy Cub! I hear what sounds like some unhappy bearings though, maybe on the mower or mule drive, or drive line/finals are a bit dry. The engine sounds great! Was the muffler actually clogged up? That's amazing! ...since they're a flow through design(no baffles). New ones aren't expensive. Glad you figured it out!

Re: Rough Idle/Backfire

Wed Jul 03, 2013 2:39 pm

Thanks! I need to tackle that grind although I havent pin-pointed exactly what it is yet. Though not mechanically inclined, I get by at my own pace and am a frequent Google-r haha. The sound dampens when the clutch is applied and rears its ugly head when in gear/neutral and letting off the clutch, driving, etc. I feel like it is noticeably louder when moving in all gears. I thought when I drained the old oil (mostly milky water) from the trans, flushed it and poured fresh oil, the grinding would have gone away. From these symptoms and having seen the videos, what do you think is the culpret?

Even though the muffler is straight through, it had all kinds of gunk caked along the mesh inside (I was surprised myself). Hosed it out, torched it, banged it around a little, hose and torch again. Looks a lot better :) AND I dont have carbon chunks spitting out on occasion.

Re: Rough Idle/Backfire

Wed Jul 03, 2013 3:08 pm

Hmm - I listened again to the second video. From what you explained it may be the input shaft bearing in the trans since it does it in neutral and in gear. Make sure it has gear oil in the transmission. ...and/or change the gear oil, could be full of water. Don't forget to grease the throw out bearing too.

Re: Rough Idle/Backfire

Wed Jul 03, 2013 3:15 pm

Hey Ray, I'm reading up on what a throw out bearing is and how to grease it but where the heck is it? Havent found anything for the mechanically inept yet explaining what I need to know. I havent greased anything except the front end. Is there a zerk somewhere that I'm looking for?

Edit: I found a link on here that covers a quick briefing on the subject. Hopefully I can check it out and report back. [url][/url]

Re: Rough Idle/Backfire

Wed Jul 03, 2013 9:04 pm

This is where the manuals can come in handy:


Items 10 thru 14 is the area you are concerned ... Item 13 is the Clutch Release Bearing or Throw Out Bearing. As you can see, the TOB is in the Torque Tube and it is greased by opening the Clutch Housing Hand Hold Cover, Item #2 and lubing the zerk through that opening.

Re: Rough Idle/Backfire

Wed Jul 03, 2013 10:55 pm

AWESOME thanks Rudi--I thoroughly enjoy any exploded diagrams of the Cub. Is there one floating around that I'm not seeing of the rear end? I'm trying to take it all in before I commit to turning the wrench :shock:

It's one thing to see the part in person, but totally different to see in, out, around and what it connects to on these diagrams. Thanks again :mrgreen:

Edit: Google was suddenly my best friend: ... 24&bih=677

Re: Rough Idle/Backfire

Thu Jul 04, 2013 8:31 am

AgTires4295 wrote:AWESOME thanks Rudi--I thoroughly enjoy any exploded diagrams of the Cub. Is there one floating around that I'm not seeing of the rear end?

Well yeah .... click on this link - TC-37A Parts Catalog (5-2-49) ... as I mentioned it is on the Manual Server. They are also available in pdf format - [url=[ Sorry, direct links to manual section is not allowed. ]/index.php]PDF Manuals[/url]. No need to google on the net, just follow the manual links, they are all there and some of them have been there for 12 years already :D

Re: Rough Idle/Backfire

Thu Jul 04, 2013 12:54 pm

Yeah I ran into the manuals early this morning. Im still figuring out this site. There are all kinds of priceless threads/info/experience on here that I havent tapped into yet. I've been a member for awhile but haven't really explored the benefits of this site.

Re: Rough Idle/Backfire

Thu Jul 04, 2013 1:32 pm

There is a lot to absorb that is for sure. That is what happens when you have the kind of community we have grown into. Lots of great info and tons of great members :D I am pretty sure you are going to like it here. We try to help as much as we can and we do point to the resources as often as we can. We will always answer yours or anyone's questions :!: :-:-):

Re: Rough Idle/Backfire

Thu Jul 04, 2013 7:57 pm

Feels family-like. I'm really enjoying this environment. Thanks again :D