I have been Fighting with my dozer for the past three years now, yes three years mostly out of frustration. Everything was working fine, and after sitting for a month I went out to start it with no luck, after playing around for quite a while it turned out it was some kind of magneto issue so I had it rebuilt at a cost of $400. I went to start it up and everything worked fine until the carburetor plugged up with cork, now I have gone through the carburetor and I went to start it and it would run on only one cylinder but at least it was running. I took the magneto back and they replaced several items on it just in case, but now it won’t fire at all even though I have spark, backfiring is all I can get. After many times back-and-forth to the shop they’ve done everything they can do and it’s something that’s on my end.

Today, after reading this post I decided to check the timing, while it’s pretty difficult to find TDC because you cannot see the piston. I noticed the M on the gear did not mesh with the other gear. I thought maybe one of the times I took off the magneto it slid out and got out of time which would explain a lot With all the backfiring.
I need someone to help me go through the procedure of timing this since I have moved the gear so they mesh but I still have it not running correctly. Thank you in advance for your help.

Better change that engine oil, looks like a milkshake!

"Rome wrote:

Better change that engine oil, looks like a milkshake!

I know, that oil is just running out the bottom of the machine, it’s not the engine oil The engine oil is brand new

Can you help me with timing?

Should be M to M. Remove mag and change then remove the cap and turn mag to set rotation for #1 which is on the left side sitting in the seat.

Looks like you need to slide that gear off the shaft and line the "M"'s up and you should be fine. And set the mag to the correct cylinder and install the mag.

My 8U has a backfire issue as well. Turns out I have a broken valve spring.
I kept thinking I timed mine wrong or a fuel issue.
Just sayin’.....
Hope you get it going again. JM

Hi Team,
the small magneto drive gear you see with the M on it must turn several times to re-align the M on the larger mag driving gear--it is actually the idler gear that drives the starter pinion..
If you keep turning the engine they will eventually align.

One thing I notice is that the bronze bushing in the mag drive gear is coming out of position in the gear--also there is a 6B6254 Circlip (Ring ) missing from the shaft to hold said gear on its shaft--- Cannot recall if the mag drive gear can come off the shaft far enough, before hitting the main cover, before disengaging from its big drive gear--if it can, then this maybe your issue--the timing has been lost.
Simply set the engine and Mag as per the scans below and remember to keep turning the pony engine until the M's align as I said above big idler gear drives small Mag drive gear.
If the M's do not align then with the big gear M aligned, in the Mag mount aperture as shown in the scans, with the engine on TDC comp. stroke as outlined re-set the small gear to align the M's.

Cheers,
Eddie B.

I have a few more questions.
It seems like the ratio between the big gear in the idler is not 2 to 1. I have timed it M to M, when I turn it 180 it is not in sync but then it comes back into sync again I believe at 360.
This whole thing has got my confidence in engines completely disturbed.

I have re-synced the idler several times, but it really doesn’t seem that I’m getting things correct. How do you guys find TDC without an enough compression to tell you it’s on the compression stroke?

I have been doing this on the left cylinder but today I thought maybe number one cylinder might be on the right side sitting in the seat. I will go back to knowing that the mag in the #1 cylinder We’re on the same side. To answer one of the questions about the idler there is no sir clip holding it in, you can easily pull it off and turn it around to the location that you want and slide it back on. I didn’t realize that there is a circle clip because it seems like the shaft is too short. To answer one of the questions about the idler there is no sir clip holding it in, you can easily pull it off and turn it around to the location that you want and slide it back on. I didn’t realize that there is a circle clip because it seems like the shaft is too short.
I will review the pictures that were sent maybe that will help. Is there a place on the a I will review the pictures that were sent maybe that will help. Is there a place on the ACMOC site where some of these manuals could be uploaded and stored for reference?

I will give this another try tomorrow and get back to you...
David

Hi,
I am sure from your pictures that the mag drive gear bushing has moved out of the gear--if it was put back flush with the gear surface then I feel sure that you may then be able to find the circlip groove on the shaft.
Thank you for confirming about the gear M alignments. Last one I did of these D318 ponies was likely 25 years ago so is a bit hazy in this 75 year old think box.

Sometimes we tend to over think these things as they at times do not follow reasonable logic--I feel sure that when the M's line up it will be in time unless the idler gear is incorrectly timed to the crank gear--to prove this again I say to set the engine to the Mag mark on the flywheel, just before the TDC mark, TDC No 1 compression stroke as outlined in the scans above and see if the M on the idler/big gear is at around the 8 O'clock position as shown in the scan below.
Cheers,
Eddie B.