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Helpful ReplyNot sure if I have a vapor lock

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Snakebyte70
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2025/07/21 13:15:51 (permalink)
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Not sure if I have a vapor lock

I have a Brute pushmower thats 190cc Briggs and Stratton engine and Ive had it since 2012. Ive never had a problem with it and have used it every year since ive owned it. Today I was mowing and I turned it off and it backfired and It wouldnt let me pull the cord to start it (too tight) so I unplugged the plug wire, tipped it back and couldnt move the blade by hand at all. I let it sit for a few minutes and was finally able to turn the blade by hand (hard to at first but it got easier to turn the more I turned it). I just did an oil change about a month ago and I always use 5w-30 full synthetic. I checked it before I started mowing and the level was fine but the way I couldnt pull the cord and not being able to turn the blade by hand made me think it was locked up. After spinning the blade a few times by hand, I was able to pull the cord and after the 3rd pull it started up just fine (for now) and I was able to finish the yard. The temp outside was about 78F and I didnt realize it but my wife put Shell 91 VTech gas in my can when she got gas for her car. does this sound like a vapor lock? Ive never had a bit of problems with this engine before so I wasnt sure if it was the high octane gas causing the problem or what? I took out the plug and it looked fine and had no oil on it at all
 
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SRTsFZ6
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Re: Not sure if I have a vapor lock 2025/07/21 13:53:25 (permalink)
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It's not vapor lock...  Sounds more like a hydraulic lock.  DO NOT FORCE THE ENGINE TO 
SPIN OVER AS fluids do not compress.   Doing so could bend a connecting rod....
 
When this happens, pull the spark plug immediately and spin over the engine-
Your looking for excess fuel leaked into the combustion chamber.  
 
Check you engine oil, that it's NOW overfilled (diluted by fuel) and if it smells like gas.
Both are indicators of a leaking carb internally flooding the cylinder / intake then the cylinder.
 
 
.

Scott
Snakebyte70
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Re: Not sure if I have a vapor lock 2025/07/21 14:16:45 (permalink)
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Thanks Scott. Can this kind of carb be rebuilt by me? Is there a youtube video on how to do it or is it pretty much shot?
Snakebyte70
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Re: Not sure if I have a vapor lock 2025/07/21 15:18:04 (permalink)
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Well I watched a couple videos about hydraulic lock on push mowers and I dont have any oil on or around the muffler. The oil has settled down to the level it was before mowing and doesnt smell of gas and theres no oil on the plug. No oil on the floor of the garage where I put it after mowing today. I wasnt sure if the 91 octane gas was bad for it or maybe the 5-30 synthetic may have been the problem. Guess ill keep an eye on it from now on. Good mower and Ive never had a problem with it till today. Thanks for the advise Scott
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Re: Not sure if I have a vapor lock 2025/07/21 18:54:42 (permalink)
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Snakebyte70
 I wasnt sure if the 91 octane gas was bad for it or maybe the 5-30 synthetic may have been the problem. Guess ill keep an eye on it from now on. Good mower and Ive never had a problem with it till today. Thanks for the advise Scott



No problem. 
 
I assume the oil level is in-between the marks..
 
It doesn't need 91 octane but it won't hurt anything either. 
5w30 oil is fine (especially for cold climates, synthetic or regular.
Just make sure it's 30wt (in the description), 10W30, or straight 30 weight.
 
In the generators I repair, I use a full synthetic 10W40 as they will run for hours
and certainly get to temp..
 
Now, there IS a safety system with an actual small brake pad that rubs against the flywheel
when the upper safety lever is released (and the coil is shorted out and spark killed).
 
The cable that activates it often wears out, get rusty inside and does not allow 
(when the safety bar is pulled in)  the engine to spin over.  
 
Check that, you can see it move usually just at the base of the main engine cover. 
 
That cable, stretched and will keep stretching (just wear and tear) till it breaks..
 
If you post a full ENGINE MODEL #, I can point out in the parts diagram where it is.
The parts diagram is VERY helpful in general when servicing your mower..
 
.  
 
 
 
 
 
 
 
 

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Re: Not sure if I have a vapor lock 2025/07/21 19:17:41 (permalink)
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I dont think the safety bar/cable is the issue, the safety cable is moving freely and is pulling at the other end. I always put a couple drops of oil down the cable at the beginning of the year to keep it moving good. I think this is the model number of my mower thats on this pdf file I have 
Mfg. No: 7800886
 BTXPV22725, 22" 7.25GT Brute Steel Deck Self-Propelled Walk Behind Mower (2012)
 
post edited by Snakebyte70 - 2025/07/21 19:20:10
Snakebyte70
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Re: Not sure if I have a vapor lock 2025/07/21 19:46:35 (permalink)
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Ill look into it more tomorrow, Im not sure whether i put the engine number on my last post or not but if it isnt right, ill take a pic of the engine tomorrow....thanks for the help...
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Re: Not sure if I have a vapor lock 2025/07/22 06:52:59 (permalink) ☄ Helpfulby Snakebyte70 2025/07/22 11:26:14

Scott
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Re: Not sure if I have a vapor lock 2025/07/22 11:24:17 (permalink)
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thanks for the links. I went out and mowed some with it today and it seemed fine...started up on first pull..oil is right on the top line and just barely has any dark to it since ive only mowed a couple times since I changed the oil and it takes about an hour to mow my yard. Odd thing is the manual says 18-20 oz of oil and the dipstick has 20oz of oil printed on it but I can only get 16 in it and if i go to 17, its about 1/8" above the line. I always check it before mowing and itll stay at the same amount forever after Ive used it and its been sitting in the garage for a week. Not sure if thats a universal dipstick that came with it and the manual is just a general idea of what it needs but if I put 20oz in it, it would definitely be way overfilled 
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