BN even running

kopeck

Member
So I got my new to me C113 engine going. It starts easily, has good oil pressure that it maintains when warm, doesn't smoke and doesn't seem to leak in any bad places (yet).

It does have one problem though, it idles unevenly/has an intermittent miss.

You can hear it here:

https://www.youtube.com/watch?v=fOYIpO3nxHU&feature=youtu.be

It does it at all RPMs and it also does it under load. The magneto and carb were swapped over from the old engine. The old engine also ran like this but I could have sworn it cleaned up under load but it's been a whie since I ran/worked it (water in oil).

What I've checked:

Set the valve lash before I started it.
Checked for air leaks using a propane torch
Played with the low speed mixture (it's about 1/4 turn from seated).
Played with the timing a bit but didn't find it had any effect either way
Thew in a set of almost new Autolite 388s..which made it run worse! It came with Champion UD16s that I reinstalled
Checked the compression and it had 90PSI per hole

It has an H4 Mag that I'm honestly not really sure about. I've never had it on a tractor that ran great BUT I've also never had it on a nice tight engine. I pulled plug wires while running and I think the miss evened out a bit with #1 unplugged. It has new points, condensor, rotor, cap and wires.

The carb was rebuilt recently with a new throttle shaft bushing. It doesn't feel like fuel to me but I'm often wrong. :)

My next step is to recheck valve lash, especially on #1.

Any other pointers?

Thanks,

K
 
well the little i did hear sounds like a governor problem. at least if the video was taken of the engine, and held steady instead of jumping all over. valve lash is not going to cause an engine surge, nor will timing. see if it runs on one cyl. by removing 3 wires for all 4 cyl's. individually. at least you will know that all 4 cyl's are performing. and they will run on one cyl. as i do that all the time. it sure appears that the governor needs adjusting.
 
The gov wont make it miss. You are using copper wires. If #1 is the culprit did you change that wire. You cant change timing on the mag they fire on TDC then advance when running to around 35deg. With the engine running use your timing lite and go from wire to wire to check if the lite is constant on each wire. Check back and report what you have found. Ive been running mags for many yrs.
 
I've got the governor set by the book (WOT, pin slides in easily), that being said I think I had to lengthen the rod on my A a turn or two to get it to settle down, I can try that. This feels more like a miss to me but I could be wrong, sometimes it's hard to tell. The governor has surged on me a couple of time but did settle down after a bit.

I'll throw the timing light on, I can also pull a wire off another tractor, I just ran out of steam last night. Oh and yes they are copper wires.

By playing with timing I just turned the body on the mag clock wise/counter clock wise after setting it at TDC. It made no difference, I suspect because like you said the mag goes to full advanced as soon as the engine fires up. I was just helping a friend go over his '40 A with a mag and that thing idled nice and smooth, I just need to figure out what thing or things are ailing this old girl.

I do have to say I'm really impressed on how these engines just want to run. I had to replace the oil pan on this one, when I had it apart I pulled the rod caps to lube them up (it had been sitting for a long time) and all the bearings had some dirt scoring, one was more then I liked but were not worn over all and the crank journals look decent. I just slapped it all together with new front and rear main seals and it makes great oil pressure. I wasn't happy about that bearing but I just told my self if I didn't replace the pan I would have never know and would have been really happy with the results.

K
 
Try a set of NGK spark plugs and I bet it will run a lot better with them. Champs and auto lite both have gone down hill in the past few years but I have found NGK plugs are still a very good brand
 
I played a bit with it before I left for work.

I think it is surging at idle, I also thing it's missing too.

I played with the adjustment between the governor and the carb and lengthening it seemed to help a bit at high idle, it still had random misses but seemed a tad better. It did nothing to help the low idle. It also will surge if I move the throttle up quickly, most of the time I settled after a few surges, once or twice it took longer. Everything is moving freely.

I haven't played with the bump spring (that's on the bottom, not the top). I'll give that a look when I get home.

I grabbed a another plug wire and that didn't help at all.

I'm really wondering if it's a two part problem. It has a intermittent miss which then causes the engine to surge.

What plugs are you guys running with the H4s? I see NGK mentioned, I like their plug a lot but I'm not sure what number I would need. The the Autolite 388 ran really crappy, I have some 386s kicking around too but I think those are resistor plugs and I know mags don't always play well with them. For what it's worth I'm not sure if the UD-16 are resistors or not. I think Autolite 3116s are not...

K
 
The carb to governor linkage needs to be without slop. the "L" bends and holes need to be very tight to avoid surge. Not binding, just not
loose. Jim
 
(quoted from post at 15:44:08 06/16/16) The carb to governor linkage needs to be without slop. the "L" bends and holes need to be very tight to avoid surge. Not binding, just not
loose. Jim


There's no binding that I can detect.

I picked up a set of Autolite 3116s, I'm going to put them in and see if that and some governor adjustment might make things better.

K
 
Only gov adjustment is the surge spring on the bottom. Better take the assy out cause the spring probably is rusted fast or broken not unusual I find most of the time the spring needs replacement
 
like gene said check the bumper spring to get that surge out...double check that hole the spring goes in with a sheet rock screw ,,tighten screw in hole ,then pullout and the last part of the broken spring will come out of hole.....that will kill the surge in gov.,,,,,,,,,,dewy
 
Good news!

The new plugs did wonders, the low speed idle lope just vanished and it ran noticeably smoother at high speed. It wasn't quite right but things were looking better.

I then went to work on the governor. The bump screw was almost all the way in, I have no idea how the acorn nut was holding on. The spring was shot, no big surprise like you guys said rusted and broken. Luckily I had a new one from my A project (need to order more parts tomorrow) so I cleaned up the threaded holder and reinstalled. I guess I got it adjusted right as the surging went away completely and it still idles down to the stop screw on the carb.

It was still kind of chuffing at low idle so I brought up the idle speed a hair (1/4 turn maybe) and played with the idle jet and it's really quite good, a HUGE improvement from this morning.

So I guess I learned that mags don't like resistor plugs, or at least my mag doesn't. The new bump spring just tied it all together.

One last question for you guys. This engine had been sitting for quiet some time. It's got new oil and filter but I'm thinking it can't hurt to drain it and replace the filter after a few hours of running. Does that sound like a good idea?

K
 
I would just keep a eye on the color of the new oil. if it gets to look dirty change it. After 30 or 40 hours, I would change it to 15-40. Jim
 
(quoted from post at 19:13:35 06/17/16) I would just keep a eye on the color of the new oil. if it gets to look dirty change it. After 30 or 40 hours, I would change it to 15-40. Jim

Sounds like a good plan. I was going to use Rotella 15-40 on the next change, from what I've read they seem to have the best package (mostly zinc) for flat tappet engines these days. I've been running it in my SM, truck and Kubota tractor for a while and can't complain.

Thanks to everyone for the help. Turns out it wasn't anything to complex...then again there isn't anything to complex about these engines.

If I get a chance I'll shoot a quick after video tomorrow.

Now I need to get back to work on my A. Having all three running well at the same time will be nice.

K
 
Here she is in all of her glory:

https://youtu.be/Xd_-_6I5mEI

Not a looker but purchased brand new in '45 by by Grandfather. I'm really happy I got running and tuned up. Of course this is a "spare" engine I purchased a couple of years ago but that's fine until I find the time and funds rebuild the original. A running tractor is better then a non-runner any day!

K
 

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