# 18.5 briggs twin partially siezed



## mrthev5 (Jul 2, 2009)

the good news, i got a mower with and 18.5. I did a quick hit with starter to see if it would fire and it did. after that, I went through the rest of the motor. I put half a quart of oil in because it was low. once i got the mower all ready for a test drive, i fired the engine again for about 30 seconds and turned it off. I went and got some 30 weight oil and put it in. When i went to start the engine, the flywheel was locked up solid. I pulled the plugs hoping for some kind of vapor lock. No such luck. after putting a socket on the flywheel, i was able to get the motor to turn but it takes a bit of force with a half in socket wrench. Prior to this, i could turn the motor by hand. is there anyway to recover this motor or am i doomed to tear it down. Let me know any thoughts you may have. I really am pretty bummed and was hoping to get this one ready to sell but it looks like that may not happen.


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## 30yearTech (Sep 14, 2006)

May just be rust on the flywheel dragging past the ignition module. Try turning it all the way around a few times and see if it loosens up.


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## mrthev5 (Jul 2, 2009)

I was hoping something like that but I turned it probably 10 times for rotation. Still extremely stiff. the starter can only move it a notch. I have to put quite a bit of force into it. Just can't believe that i shut down the motor and it siezed in the time it took me to got the oil and try to start it. I can it a light squeeking almost like the cylindars are dry. Any other ideas...


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## mrthev5 (Jul 2, 2009)

So I guess the next pertinent question, is the motor worth rebuilding. I know if will require rehoing of the cylinders and at the very least new pistons and rings from my limited knowledge.... If so, where is a good place to get the parts and Gasket kit?


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## 30yearTech (Sep 14, 2006)

Impossible to tell without tearing down and inspecting. The pistons and rings are probably alright, they tend to seize on the crank bearings and connecting rods first. If the upper and lower bearing surfaces are still alright, may just need a little polishing of the crankshaft and possible new rods.

The only way to tell if it's worth it, is to tear the engine down and have a look inside.


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## pyro_maniac69 (Aug 12, 2007)

are you sure that the starter is dropping down, and you aren't fighting the starter at the same time? I've noticed that to be a common problem on the oppser motors


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## mrthev5 (Jul 2, 2009)

spun the starter down and removed the spark plugs. I wish there was a simple issue but being that i can hear the pistons with almost a scraping sound when i move it, i really believe the engine needs to be dissassembled. 30 yr, I will look at the components you have recommended. Thanks for the advice.


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## pyro_maniac69 (Aug 12, 2007)

ya, the really sounds like it, but don't really feel bad, because briggs had a problem with oiling on opposing cylinder engines, now if you can find with that has an oil filter and full pressure lubrication, that motor will last dang near forever


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## smallengineguru (Jul 12, 2009)

you said a "scraping" noise???.....souds like it may have broken rings and badly scored the cylinder walls. you gunna need to take the heads off and have a look. taking the heads off is only a 1/2hr job......then you will REALLY see in what condition your engine is in.

cheers


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## dj722000 (Oct 29, 2008)

18.5 hp briggs, can go to briggs site and check out the ipl on that for a break down. Definitely sounds like you have a broken ring or something. I would pull the head and check before you keep trying to turn it or you may have to have it bored from gouging if its a broken ring.


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