Cub 100 slow crank.....ACR?
 

I was given a nice Cub 100.....I have several others (wife and kids snicker), Its all original with fenders and what I was told a replacement short block some years ago.....I think a 1964 ....I had it running a couple years ago....real hard cranking and would stall as soon as I loaded it. Well I finally got back to it and cranking is awful even with additional jump battery....I went thru all the normal diagnosis battery...cables....starter...etc.....adjusted valves....timing....finally decided i dont see a bump on exhaust valve as I roll it over.....so I lifted the engine and took cam cover off. I see a hole in exhaust cam lobe...with nothing in it.....and I see a couple weights flopping around on front of cam...a very small wire that may be a spring end on a weight...looks to thin though. Question...How do weights on the front of cam gear actuate the exhaust valve which is behind? Internally thru that hole? and what can be done to correct this? pull motor and replace acr? Cam? does anyone have pictures? I just want this nice old Cub to be able to mow again...

Ok well I am now responding to my own thread...I found the thread about slow cranking and two peice camshafts....Which is obviously what I have and why it would stall so easy....The way I was setting timing it was firing 40*before TDC....but....it still cranks hard....the battery tray is perfect for an automotive battery and I could put larger cables? whats the thoughts on that?

Welcome to OCC..... :Welcome2:

First thing I would check is the Battery Cable connections. This would apply to both cables and both ends. Make sure they are clean, bright, tight, and down to bare metal. This is essential for getting the power to the Starter.

Next, I would have the battery charged up and have a reputable shop "load test" the battery. If not up to specs, then replace the Battery with the highest "CCA" rated battery that will fit in your battery compartment.

Now, lastly would be the Delco-Remy Starter/Generator itself. The possibility exists there could be a problem with this. If you suspect so, take this to a reputable Repair Shop and have it professionally examined. If there are issues with it, by all means, spend the money to repair it as opposed to buying the cheap Chinese junk you see on the internet.

Do the above and report back.

If you have the two piece cam then it is a timing advance cam not a ACR cam. The timing advance cam has the fly weights on one side of the gear and the ACR cam has the fly weights on the other side ( lobe side ). With the timing advance cam, the points should be set on the "T" ( on fly wheel) whereas with the ACR cam it should be set on the "S". I just went through this ordeal with my 100, very hard starting, check out my thread ( ACR questions). I got a used ACR cam out of a 102 and swapped them and just got it put back together tonight, fired right off, couldn't be happier!