Starter gen won’t turn on compression stroke

[Chris1055 106]

Hi,

 

I recently acquired, a 875 which I’m very pleased with, when I got it it started hard but had an old battery. Put a brand new Napa battery in it and it still struggled but it did start. Ran really good, every time a ran it though it struggled more and more to start. Checked all the switches wires, bypassed the switch ect. It also charges like it should. Pulled the spark plug cranks nice. Put plug back in cranks than stops on compression stroke and wire heats up doesn’t want to get passed it. Any suggestions?  Also I would like to start a thread on this tractor has some nice history. I’m the second owner. But I’ll start that on the tractor

[ebinmaine 63,133]

I don't know when Kohler started with ACR. Others could answer that.

Perhaps if you do have that it isn't working?

Do you have a "known good" S/G you can throw in for testing?

 

 

On a side note but certainly related...

The wires that are getting hot likely need to be replaced or at the very least, cleaned up.

They really weren't big enough in the first place so when dirty/corroded they'll heat up quickly.

Also check all related grounds. Bad ground will cause a hot wire.

 

 

Nice tractor!!!

 

 

[squonk 38,926]

Replace the cables. It may not fix it but after 55 years, they are shot!

[The Tuul Crib 7,332]

That does sound like it could be 

an ACR spring . Is there a removable 

cam shaft cover on the carb side? 
if so you can remove the cover and you

can tell. 

 

[Ed Kennell 35,769]

Jump a good battery  directly to the starter post.     If it spins, you have bad wiring and/or switch.    If it doesn't spin, get the start/gen rebuilt.

[953 nut 51,680]

Like @ebinmaine said, when a wire heats up it is telling you that it needs to be replaced.

Another consideration is your ignition timing may not be correct. If the spark is occurring too soon on the compression stroke it will make cranking difficult. Your ignition points can be adjusted to set the timing. If you have a timing light you can check the timing with the engine running, the site hole is in the back of the engine bearing plate just below the S/G mount. Without a timing light you can use static timing as found in the Kohler Service Manual.

Gapping the ignition points at .020 has always been the standard answer to how points should be set. That probably will get you into the ballpark where the engine will run, but with a bit of additional effort you can improve the engine’s power and performance.

The Kohler engine manual in the Red Square files section covers two methods for setting the ignition timing, Static Timing and using a Timing Light. This manual is a relatively new manual and it overlooks the fact that many of our engines were built prior to the ACR (automatic compression release) camshaft.

Earlier engines (mostly 1965 and earlier) had a Spark Advance camshaft that can not be timed using Static timing. At rest (and very low RPMs) the timing is retarded to fire slightly after TDC. The timing mark (SP) on your flywheel is at twenty degrees before top dead center but at rest the points on these engines break about ten degrees after top dead center. The only reliable way to check or set the timing on these engines is with a timing light.

There are a couple ways to determine what camshaft you have. Presuming the camshaft in your engine is the one it was born with the data plate on the engine has a suffix that can tell you what camshaft was used. The table below will tell you the suffix applicable to your engine. The other way to determine what camshaft you have is to remove the cam gear cover and take a look. If you see a mechanism attached to the cam gear it is the ACR cam.

 

 

The following engines have the spark advance camshaft;

K-141, Suffix prior to “C”

K-161, Suffix prior to “J”

K-181, Suffix prior to “D”

K-241, Suffix prior to “D”

[moe1965 718]

I had the  same issue on mine as well . I had it rebuilt. They turned and cleaned all the contact points in the starter generator. It was full of carbon dust as well haven't had a issue since then.  Rebuild was around 25 bucks.  

[rmaynard 14,897]

Always start with the simple stuff first. As Ed said, using jumper cables and a known good battery, bypass everything and go directly to the starter. If it starts properly, it is probably the cables or weak battery. After that, check the timing. If that's okay, it's probably a weak starter. Easier to rebuild a starter than to replace an ACR.

 

 Don't overthink it. I have an 857 with a broken ACR, and it starts fine without it.

[WHX?? 46,772]

Nice lookin survivor there Chris. I have a 1055 with no ACR and if the SG catches it on compression stroke it will just spin the belt. If the belt gets wet as happens at shows forget it. It will not grab at all. Might just the brand of belt I have on her too. Since I see you have the guard off belt is goodntite??. Possible a weak SG? As mentioned I would go with some new cables and polished connections. Does the motor spin ok if you get her by the compression hump and get her wheeling?

[Chris1055 106]

Thanks for the help, so far I pulled the head I wanted to check piston and valves anyway. Set points, and it still cranks half rotation and stops when it hits a load. It has a fresh belt. Everything checks out. I’m thinking the generator needs to be pulled and cleaned possibly rebuilt. I’ve done them before, well brushes Field coil and bearings if it needs more than that I’ll have to send it out. I’m going to put a gen on it that  I know is fine out of my 856. If it cranks all the way I’ll start digging into the old gen. Also the engine is k181 A . So it is a earlier model with a spark advance cam. I’m pretty sure it’s a weak gen. I’ll keep you guys informed. I’m going to do the swap now fingers crossed! 

Edited January 17, 2020 by Chris1055

[Chris1055 106]

Here’s the donor. Used the same battery and drove the 856 into the shed. Besides needing a bearing this is a strong generator so hopefully this will crank the 875 

[Chris1055 106]

Also as a side note this tractor was yearly serviced until being put away in 2008. I have all the receipts. Like this Kohler belt for the gen in 2005 

Edited January 17, 2020 by Chris1055

[Chris1055 106]

Verdict not the generator.

Edited January 17, 2020 by Chris1055

[Chris1055 106]

Let me know if you guys can see the video I hope you can 

[ebinmaine 63,133]

1 minute ago, Chris1055 said:

Let me know if you guys can see the video I hope you can 

Others may be able to. I can't look at video unless it's on YouTube because it takes up too much space on this phone.

 

 

Perhaps, move on to replacing a couple of wires?

 

[Chris1055 106]

The wrapping sound is the belt loose Drive belt  don’t be alarmed 

[pfrederi 17,147]

I can see it a bit out of focus.  What gauge wire are you running from the battery to the A terminal and from ground to battery Look kind thin in teh video. 

 

I would try some heavy jumper cables.

Edited January 17, 2020 by pfrederi

[lynnmor 6,777]

Do that video again with the spark plug removed, see if the noise is still there.  Also rotated by hand with the plug out to feel for any resistance and listen for noise.

[pfrederi 17,147]

Another check what is the battery voltage reading while you are cranking??? 

[Rob R 951]

Suggest in addition to everything said chk the valve clearance especially on the exhaust side. 

[Chris1055 106]

[Chris1055 106]

Spark plug out, 

[Chris1055 106]

Checking valve clearance now 

[Chris1055 106]

While I’m at it. I bought new cables and connectors. What are your guys thoughts on putting a solenoid on these. I’ve heard somewhere that you get more cranking amps. I used mount them underneath the gas tank but I really don’t want to drill any holes in this horse. 

[Ed Kennell 35,769]

I never did like all that Amperage going thru the ignition switch right behind the fuel tank.  

   BTW, did you ever bypass the  switch and wiring and power the starter directly on the post?