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Discussion Starter · #1 ·
I've been fighting an issue for a couple of years now with this engine. It started burning oil really bad so I tore it down to check the rings. They seemed fine but I replaced them anyway, along with a new crankcase breather. This did not change a thing. I thought maybe the bores were slightly egg shaped so I bored it .020" over with another set of rings (gapped .009") and obviously new pistons. The guides appear to be fine and the valves were lapped in. I continue to have the same problem. I use as much as half a quart of oil in a 20-30 minute time frame.
I installed a pcv valve inline with the breather and ran a tube to a water bottle to see if oil was really being pumped into the intake. Sure enough, I could fill 8oz in the same time as mentioned above.
Next I installed a fuel shutoff valve and looked into replacing the fuel shutoff solenoid. It was about 75% of the cost of a new carburetor so I went ahead and replaced that too. At this point, literally everything is brand new and the tractor still smokes like crazy. The oil is surprisingly clean. My lash was slightly off but the motor did not turn over hard. It's almost as if I have extreme crankcase pressure. A local small engine guy has looked it over and is completely stumped as well. What's left that we're missing?
 

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This is a strange one for sure! Sounds like you covered it all. Just for hahas, it isn't actually blowing the oil onto or in muffler also is it? Does it load up on oil at idle? I am wondering if the heads them selves are issue? Valves might actually have bad seals?
So hard to know from this side of screen! I have one of these right now and notice the sump is leaking on mine. I know of issues with air cleaner sealing on it causing faster wear due to dust?! You covered those wear issues though?
 

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Discussion Starter · #3 ·
This is a strange one for sure! Sounds like you covered it all. Just for hahas, it isn't actually blowing the oil onto or in muffler also is it? Does it load up on oil at idle? I am wondering if the heads them selves are issue? Valves might actually have bad seals?
So hard to know from this side of screen! I have one of these right now and notice the sump is leaking on mine. I know of issues with air cleaner sealing on it causing faster wear due to dust?! You covered those wear issues though?
I do not see oil leaking anywhere. Most recently, it appeared that the smoke was only coming out of the exhaust on cylinder 2. I have the head off and the bores are still perfect, the valves are snug in the guides, and the valves seem sealed but I can't tell 100%. The seals are new as well.
A week ago was the first time it smoked at idle. It usually only happens when a load is put on the engine, when engaging the blades.
And yep, I upgraded the air cleaner. I can't remember if it was a reissued part or from another motor but I found the info on here a long time ago and swapped everything over.
 

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Is the oil pooling in the valve covers instead of draining back to the sump? Dipstick sealing ok? Just some off the wall thoughts. :dunno:
 

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A long time ago the place I worked at repaired an 8 HP Briggs engine. We finally sent it into Briggs and they found the block casting had been poured to make the engine at to cold a temperature and the block was to soft to use. In that case it was on new equipment so it was replaced but it took 6 months to get it resolved with Briggs. Roger
 

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Discussion Starter · #6 ·
The dipstick tube is more loose than I'd like but it doesn't leak. The dipstick itself seals fine. There is considerable oil in the valve covers when I pull them off.
 

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Discussion Starter · #7 ·
I squirted a good dose of oil onto the top of the head (sitting flat and level) around the guide/seal last night. Tonight, I could see a bit of oil on the underside of the exhaust valve. It makes sense as the bowl is full of crud however, there is no play in the guide. I was hoping to just change the seal but there is only a seal on the intake side. I find it hard to believe a guide with no noticeable play would be the suspect here.
 

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Discussion Starter · #8 ·
Things are back together. The lash on the exhaust valve of cylinder two was a little sloppy. I'm not sure how that happened but everything is fine tuned now. I used the tractor for about ten minutes this morning. I'll let you see the problem for yourself:
No one has been able to figure this mess out. I've had some pretty good minds looking at it and I've wasted tons of time and money.
 
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