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Discussion Starter #1 (Edited)
I replaced every component, switch, wire, fuse, coil, etc trying to chase down my no spark issue. Finally I found it to be the lifter, not lifting the points. I pulled the tappet out, chocked it up in a drill and polished it with 400, 800 then leather. I polished the inside of the journel that it rides in as well. It's as smooth as butter in there but as soon as I bolt it to the engine, it won't go up and down. Please look at the photo and tell me if that piece of metal (in the hole in the block) is supposed to be there. I think that's what it's hitting/binding on. It almost looks like that was some sort of bearing that slipped over. btw. I can watch the cam lobe spin when I crank the engine. I can loosely hold the tappet in the hole without the guide and feel it going up and down. Any help appreciated. Thanks! Also... this has been a recurring problem. Tractor has done this several times and each time, I remove the points check the tappet and put everything back together and then it works again... until I shut it off... then no start and the circle begins again.
259616
259617
 

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Discussion Starter #3
Sure looks like your cam bearing moved a bit creating interference for your points plunger.

BobP
Damn... didn't want to have to pull the motor and break it down. Can't afford to buy a repower right now. This sucks. How in the heck would the bearing move?
 

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ive had that bearing move on onans before put bearing mount on it during reassembly I think the bore expands when warmed up and then causes bearing to move.
 

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Discussion Starter #5
I didn't want to believe it was true... just looked up what that bearing looks like... I guess that's why they use red thread lock when seating bearings.

259622
 

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Discussion Starter #6
I'm just posting this for archival purposes for the next person who runs into this problem. I just found out after some additional research that that bearing did more than just "spin" as I originally thought. That notch that appears to be perfectly suited for the points lifter isn't for it at all. it's an oil hole. That bearing shouldn't be in view at all. It's actually working it's way out of the motor. I did some looking and on that side of the motor, that bearing is actually set in quite a ways from the edge of the block with a special tool and then the hole in the block is plugged with a special plug. So part of the camshaft that lifts the points system is actually outboard of the bearing. See attached photo. At least this is what I believe. Anyone who's broken one of these engines down care to confirm?
Thanks,
Joe

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Is this an engine that you have had, and run for extended time, or a new purchase? I ask because it looks to me the bearing was just installed incorrectly. The bearing with the larger notch is supposed to go at the other end of the camshaft.
According to the Onanparts site, the correct bearing for the rear end of the camshaft, which is the front mounted in a Deere tractor, has the oval points plunger hole.
I have worked on quite a few of these engines, and have seen a few of the narrow bearings at the gear end of the camshaft, but not at the other end. I think the narrow bearings were used for a short time, and then they went back to the wide bearing.
 

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Discussion Starter #8

Is this an engine that you have had, and run for extended time,
I've had this tractor for several years. I'm the second owner and as far as I know the motor has never been out of it. The rings are pretty worn and it burns a bit of oil. I do believe it was low on oil one day cutting this summer and it got super hot. everything went to crap after that. We had a crazy hot summer here in CT and it was a 100+ degree day the day that it shut down due to what I found was the main breaker going out on thermal overload. After that this ignition problem started.

It's my primary snow mover for the winter :) So I need to get it back up and running. I've also got the MCS for it and a 60" deck so it's my main cleanup machine for the fall leaves.

259644
 

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Discussion Starter #9

According to the Onanparts site, the correct bearing for the rear end of the camshaft, which is the front mounted in a Deere tractor, has the oval points plunger hole.
I have worked on quite a few of these engines, and have seen a few of the narrow bearings at the gear end of the camshaft, but not at the other end. I think the narrow bearings were used for a short time, and then they went back to the wide bearing.
So... assuming that bearing is correct, you're suggesting that that notch "IS" for the points plunger? Any chance I can stick something in there and pry it to get it to spin the 1/8" or so to clear that hole? I'm guessing not but thought I'd ask...
Thanks,
Joe
 

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It is normal to have the small oval hole for the points plunger. The notch works as well. If it is loose enough that you could pry it over even a 1/16", it would probably turn back again. If the bearing is loose in the block, that is definitely not good.
 

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Discussion Starter #11
Thank you all. I'll try to pry it back and see if it limps long enough for me to order the driveshaft and pto adapter from ebay and a predator engine from harbor freight. I'll video document the conversation process. It does not seem as if anyone has done that yet..
 

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The bearing likely slipped when the engine was excessively hot. If trying to pry it back doesn't work, why not ream the notch with a small round file just enough for the points push rod? It seems you have nothing to lose.
Harold
 

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The bearing likely slipped when the engine was excessively hot. If trying to pry it back doesn't work, why not ream the notch with a small round file just enough for the points push rod? It seems you have nothing to lose.
Harold
I doubt a file would be able to do much there with the cam in place, but maybe a dremel with a flat smooth end?

As with a file, the chips wouldn't be good for the engine, but if there's nothing to lose it might be worth a try.
 

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Discussion Starter #14
Thanks for all of the good ideas. Going to head out to the shed later today. I'll try carefully prying the bearing first. If that doesn't work I'll use a cylindrical grinding bit on a dremel and remove the dust with a magnet. I just need it to last 2-3 weeks while I gather the parts to do a repower.

I guess the next big decision when and where I'm going to find the time and spare change to spend ~$120 on the driveshaft and PTO adapter, $830 for the new HF Predator motor, some 1.5" square stock to make the engine mount and a free weekend.
 

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My thinking with the file was to not generate abrasive residue from the stone that cannot be removed with a magnet. I would cut or break a small file and grind the end flat so there are teeth at the very end. Rotate the cam so the lobes are away from the hole. Good luck with whatever unconventional method you try.
Harold
 

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Yes, I was thinking of something like a carbide steel cylindrical cutter, not an abrasive grinding tip.
 

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Discussion Starter #17
And just like that... A screwdriver in the slot and another one behind it to act as a fulcrum... Quick jerk and the bearing moved back into place. Points reinstalled and she fired right up.

Now I have no illusion that this is a one and done fix. I'm still planning the repower but I'm thankful for the support and ideas provided by this community.

Sent from my SM-G975U using Tapatalk
 

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I'm surprised you did not put a dab of red Loctite on the surface before trying the screw driver and fulcrum method. See if that helps hold it in place longer.
 
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