Old Sears Suburban SS12

jwstewar

jwstewar

Senior Member
Staff member
I've got Dad's old Sears Suburban SS12. It is in pretty decent shape, even though I used and abused this machine for several years before I bought the NH. I don't remember exactly what happened, but I remember it wouldn't start or something. This was back in 2002. Dad took the tractor back to his house and started doing some trouble shooting on it. I know he had the coil and the mag tested, both were supposedly good. Now here is where it starts getting interesting. Dad then started troubleshooting a bit deeper. He started disassembly things. Apparently between him not feeling well and such maybe he couldn't remember, he didn't put things back together, but he would take more apart. Well, as part of my commitments to him before he passed, I said I would get his baby running again - already have fixed a couple of his other items including his snowblower and his "new" Snapper riding lawn mower that I bought him in 1997.

Anyway, this is where we are today. I've got the tractor at home in the barn and I think I have most of the parts.:hide: But in his disassembly he disconnected probably the only safety switch on the darn thing. I put new ends on the wire on the actual safety switch and plugged the wires back in to it, but I've got two other problems. I can't find where the other end of the wire is supposed to plug in. I'm assuming when the switch is depressed it is supposed to complete the starting circuit, but without knowing where this is, I have no idea if he jump it or not. Second, I can't figure out how the brake/clutch panel is supposed to engage the button.

I've looked on Sears' website for a manual, but the one for the tractor is some little cartoon like drawing, but the one for the plow and the mower deck are much more modern looking and go into much greater detail.

Anyone have any ideas on either of these? I've attached pictures so you can see what/where I'm talking about.
 

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It was raining here Saturday afternoon so I had a chance to work on this some. Looking at the electrical diagram on Sear's website and the parts diagrams, I think I have this figured out. Looks like I was right on the brake switch, however there is a little tab held on by a cotter key that is broken off. Who knows where, when, or how, but it is gone. So it won't actually depress that safety switch. Of course, not available. I've sent a msg to a guy on ebay to see if he would have one, no repsonse yet. The second wire I posted looks like it goes to the attachment lever safety switch. Kind of weird on the Sears' diagram, it is inline with the brake safety switch (that makes sense), but it has a circle around it like it was optional. I see nothing on my attachment lever that would correspond to this. Since this tractor didn't originally have a mower deck, would they not have put that safety switch on it and just jumpered the wire? I don't know, but in the short term that is what I'm going to do for both of them.

I also found, that it looks like the ignition switch is bad. I can get continuity through the start circuit, but not on the run circuit. I'm going to stop tonight and pick up a new switch for it. I then found the one wire that goes to the motor from the ignition switch, I thought it was a ground wire, but now it seems to be the hot wire from the ignition for maybe the magneto? It is labeled on the diagram as M. The other 2 wires are B - coming from the battery and S - solenoid. There is then a ground wire with a loop that goes around the threaded portion that sticks through the dash.
 
Sounds like yer on the way to gettin her runnin again. Something like that can make ya say things you wouldn't normally say.
 
Yeah, got the ignition switch reinstalled tonight. I installed jumper wires in place of the two safety switchs and got the starter turning over with the ignition switch. Now I need to pull the cover back off the engine and hook the "M" wire from the ignition switch to the magneto somewhere. Not sure where that is, but won't know until I pull that cover. I was also able to get the motor turning over a bit tonight. Wasn't necessarily a bad thing to turn the motor over a bit w/o a spark or fuel since it has been sitting so long.
 
I stopped last night and picked a battery up for this tractor.

I've also been looking at the manuals and stuff for the engine and tractor that I have found online and folks have sent me. The wire that I thought went to the magneto actually goes to the side of the block (which is where I thought it went originally based on where it was and such). I hooked that wire back up and the battery. No spark. Pulled the plug wire and I can't see where it is trying to jump to the plug.

Not sure where to go at this point. I think I remember Dad telling me he had the magneto tested and it was good, but I can't swear to that. I'm not sure where to from here. I think there is a gap on flywheel that can be adjuster to the mag. Maybe that is what I need to do? Not real sure where to go next. Maybe pull the mag and take it to the local mower shop and have it tested again....
 
I don't know what engine you have, but when I lived in Florida I used to have a lot of trouble with Briggs engines getting spark because the magneto rusted. I wuold have to pull the flywheel and sand both the magnet and the ends of the magneto and regap. Briggs or their dealers supplied card stock of a specific thickness, and the manual said how many of those cards had to be used to set the gap. The magnets pulled the poles of the magneto snug against the cards, then tightened the screws, and voila! Correct gap. Engine then started right up. HTH.
 
This is a Tecumseh HH120, but I think from how you are describing it, it is the same concept. Haven't had a chance to get back at it, I might have a few minutes tonight or tomorrow night.
 
I worked on it a bit tonight. I pulled the flywheel and got to looking real close at the pulse transformer. I notice the wire coming from the magneto had been pinched at some time. I pulled it off and cut the end of the wire and soldered a new end on it along with a new connector that went on to the magneto. I then also sanded the magnets and got them clean. I look how to adjust the plate on the flywheel, but when you loosen the screws they just back out without moving the plate. I put it back together being optimistic:hide: Turned the engine over and it didn't try to start. I pulled the plug and ground the edge of it to the engine. I can see a blue spark, just not sure how strong it really should be, but this one was decent. I'm going to stop and get a new plug tomorrow and put some more gas in it and give it a try. I'm also going to look and see how and if they can be to adjust the valves. I'm not sure if this has timing that can be adjusted or not, I don't really see how it can be as it driven off a woodruff key in a groove on the crankshaft corresponding to a groove on the flywheel.
 
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New plug is in, but still no start. Really strong spark now. Pulled the new plug it didn't appear to be getting fuel. Pulled the carb. It is dry as a bone. I disconnected the carb from the fuel pump and turned the engine over. The fuel pump appears to be moving fuel well. A lot of fuel came out with just a couple of revs of the motor. So getting ready to read the manual on the carb.
 
homemade said:
stuck float needle or just a piece of dirt in there
Click to expand...
That would be my first 2 guesses.

Do you have any starting fluid? A quick spray into the carb and try to start. If it fires up for just a second or 2, you're real close to getting it done.
 
I thought of the starting fluid last night, but when I went to my shelf that I keep all of that stuff on, 8 cans of PB Blaster, 3 or 4 of WD-40, 2 Engine Degreasers, 1 battery acid cleaner, 3 Brake Parts Cleaner, 4 Silicone Lubricants, and a few other odd balls tossed in there, but no starting fluid.:cuss: Guess I'll have to stop tonight on the way home tonight and get some. When I stopped to get the plugs last night at Advance Auto Parts, another customer was there and he heard me talking to the clerk. He kept trying to buy it from me. He has 3 of them and his brother has 2.

Right now the carb is off, so not sure if I will put it back on to try the starting fluid, or take it apart and clean it while it is off. Once I get it fired up, I will then replace the fuel lines and such. They are probably original and really starting to show their age, but no sense doing anything like that until I make sure it'll run.
 
**&(*^&*&^*&(&)&(*) grumble grumble, I came home tonight and instead of going in and changing close and looking at the diagram, I walked to the barn and started messing with the carb. I broke the high speed screw. :cuss: Fortunately I found 1 new one on ebay. $13 & free S&H. Also ened up ordering a new drain valve for the bowl and a new O-ring for it. Spent a total of about $20. After I order those I found a NOS carb for $60.:cuss: Should've just ordered that. If these parts don't work I will order it, the guy had 5 of them. I don't see all 5 of them selling before Monday or Tuesday.

I did pick up some starting fluid and carb cleaner and got the carb cleaned up fairly well. I was also able to blow through the area where the fuel goes into the bowl. The bowl was still completely dry on the inside so I think you guys were right on the stuck float.
 
OK, a little bit of an update on this. I was able to find the part I broke for the carb. Even managed to get a rebuild get for it. I cleaned the carb and can get air to go through everything and everything moves free. I replaced all of the old gaskets and such and replaced with the new ones. Still no start. Even spraying ether in in, still no start and doesn't even try. I bought a compression tester. It is building 120 PSI when I crank. So now I'm kind of stuck, not sure where to go.

In short:

I've got good spark now
rebuilt carb
120 PSI on the cylinder
Still no start even with Ether
 
Damp. The other thing I forgot, occasionally with ether, I will get a backfire but have only had a few of those.
 
It's early and coffee has just started but it almost sounds like the timing is off. Is it even possible to get the timing off on these small motors? If the spark isn't happening near TDC on the compression stroke, it won't run but could backfire now-and-then just because the fuel and spark do meet each other once in awhile.
 
I see homemade and I are on the same page. What I'm not recalling is how to adjust.
 
OK, I'm with you guys, but I haven't figure out how to time this engine yet since the flywheel is held on by a woodruff key. We are camping this weekend, looks like I need to take my documentation with me and do some studying of it....

Thanks for everyone's help, I'll keep you informed.
 
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