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Briggs & Stratton Intek plus 18.5 excess oil blow by


Nick Skjonsby's Avatar
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06-09-14, 08:07 PM   #1  
Briggs & Stratton Intek plus 18.5 excess oil blow by

ok im new on here. I got a riding craftman 42" mower from a guy. he said it quit one day while driving and said engine was locked up. The guy is not the most mechanical. It sat around for 6 months or so and I put a ratchet on the flywheel bolt. turned hard for first couple turns then turned better. was missing spark plug the whole time without me knowing and sat outside in the winter with hood down. had to replace battery and take apart starter- found broken corner of ?com? outer magnet inside starter. cleaned and reassembled. had to start engine first few times with starter and air drill with socket on flywheel. will start with just starter now with everything put back together. runs great. made 2 laps around yard tonight and smoke coming from engine. oil dripping from "circle thing" with 2 fuel lines and 1 line to oil fill tube. took dipstick out with engine running and can see and feel alot of pressure coming out of sump. I'm not a small engine guy. went to school and work on cars. did some reading and possible head gasket? My gut feeling would be rings since engine was "locked up" according to the last guy. and help would be great. thanks

 
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cheese's Avatar
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06-09-14, 10:47 PM   #2  
If it locked up from lack of oil, I would be surprised if it didn't need rings, rod, possibly piston, and likely balancer, and it probably has aluminum transfer on the crankshaft. Usually they aren't worth fixing.


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06-10-14, 05:30 AM   #3  
I can't say for sure it was locked up,the guy said it just quit one day and I think he assumed it locked up. when I turned it over it didnt seem to break free or anything, just a constant turning.

 
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06-10-14, 09:34 AM   #4  
Okay, I see. Check the oil... is it really thin? Overfull? Does it smell like gas?


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06-11-14, 06:20 AM   #5  
It is low on oil. prob around 1/4 to 1/2 qrt from running for about 20 min.

 
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06-12-14, 12:38 PM   #6  
That motor is known to blow the head gasket, poor design if you ask me. I blew mine within a year of ownership. It blows between the combustion chamber and the valve push rod galley. When this happens, excessive blow by is pushed into the crank case, which in turn pushes oil out the crankcase breather and into the intake path. The result, depending on how badly it blows is a yard full of blue smoke. It's an easy repair, plenty of info if you Google Intek Head Gasket Failure.

A simple back fire is all you need to blow the gasket and for some reason these motors are prone to a back fire. Mine used to back fire or pop if it was turned off on low speeds. On full speed, no back fire. My brother had a John Deere with a reverse interlock. It would cut the engine out if the blades are engaged and you put the tractor in reverse. Pulling it back out of reverse would cause the ignition to cut back in and result in a nice big POP! That's how they blow.

 
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06-13-14, 06:39 PM   #7  
ok. good information. but i dont like parts changing. how would a guy diag head gasket failure. leak down test would tell you air is getting into sump. either ring or head gasket correct? I changed filter and oil tonight. added a little sea foam to oil. ran it for about 10 min. only smokes under load. ( I'm color blind keep in mind) I think it was blue smoke when it was going through heavy grass and at a stand still when throttle was moved from idle to high speed it has a puff of white smoke.

 
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06-13-14, 09:47 PM   #8  
Sounds a lot like rings. usually a bad head gasket exhibits itself by burping a ton of oil through the breather into the carburetor at intervals, creating billows of bluish-white smoke. Then it stops until the crankcase pressure eventually gets high enough to burp out like that again. I had one doing that today actually. I think all the ones I ever fixed that were smoking due to a head gasket were doing the same thing.


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06-15-14, 06:12 PM   #9  
thanks alot guys. after running it for around 30 min it really starts to smoke. i'm going to try and do a leak down test with valve cover off and see what i can come up with. where is the best place to get parts? cheapest engine i can find is around $750. through sears around $1100. if anyone knows of a cheaper engine please let me know before i sink money into this one.

 
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06-15-14, 06:25 PM   #10  
When you had it running was there any engine noise like rod knock? You'd notice it more if you rev the engine and listen when the rpms come down.

 
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06-16-14, 06:05 PM   #11  
did not hear any rod noise

 
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06-17-14, 12:08 AM   #12  
You can usually find engines pretty cheap on ebay.


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06-17-14, 10:33 AM   #13  
I suspect what you have, based on your measurements is an engine that needed bored but the boring took it past the oversized piston/rings. As the rings seated in and wore a little, the ring gap became too large to contain the compression going down and the oil coming up. The compression blows the oil up past the rings.

The little bit of time it takes is just the time the oil takes to thin down with operating temperature.

If you find the ring gap is unusually large, looking for another engine would make a lot of sense.

 
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12-31-14, 08:39 AM   #14  
I cannot find anything on head gasket REPLACEMENT!

What is missing is the tightening sequence with a diagram of bolt locations. Other specs like valve clearances and torque values necessary to reassemble an engine that has been torn down is also not readily available. That's why I came to this forum in the first place - to get these specs!

Thank you!


Last edited by j14152; 12-31-14 at 08:39 AM. Reason: spelling
 
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