# Briggs & Stratton 16 hp. I/C twin knock'in



## bsman (Jan 22, 2006)

Hey guys,
I am new to this forum, and wanted to ask a question. I have a B&S 16 hp. Twin II I/C engine. This past summer it started to knock, and eventually came to the point of not starting. So I took it upon myself to try and fix it. I started by removing it from the mower, and taking the headers off and cleaning the carbon deposits. I read some where that excessive buildup can cause knocking of some degree. Anyways, I was skeptical that that was all and proceeded to remove more parts. I removed a side panel, that let me view the crankcase etc. When I rotated the flywheel, a part of the crankcase joint was scraped, and knew that that was my problem right there.

I was wondering if you could help me out, as of what to do next, and what the possible cause could have been.

P.S. Any help for this young'n would be helpful. Thanks!! :thumbsup:


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## bugman (Aug 12, 2004)

ok, knocking... then wouldn't start.... have you opened the engine up? take the sump off and look? did you take the heads off to clean the head and piston tops?, did you rotate the flywheel to see if both pistons go in and out, and both valves open on each side?


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## bsman (Jan 22, 2006)

Yep to all. I took the headers off first, cleaned deposits, rotated fly to make sure everything was in check. But when I got to the left side (v-twin) the exhaust valve was so carbed up that it wouldn't even open. Once I got all of the carbon off it worked as it should. I didn't take the sump off, only a side panel that let me view in it. Where the pistons connect to the shaft, there was a nice worn spot on the joint thingy. (can't think of the name right now) I think I'll take the sump off and I be able to see what it has been knocking on. Sometime, somewhere, something got bent or out of shape. I'm just trying to figure out as to what it could be.

Would I be better off just replacing that part??? Let me know, thanks guys


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## bugman (Aug 12, 2004)

yeah, it'll have to be gone in further to see, that shaft is the crank, was it ever run low on oil?


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## bsman (Jan 22, 2006)

it's always been maintained at the end of every season, gas removed or stabilized, always good oil in it. The only thing I can think of is that it has been ran at high RPM's when mowing. Before it died, it started to blow blue smoke and surge/hunt, which led to think it was a carb. problem. So i'm going to either repplace it or rebuild it. Then one day, after running it, not at high RPM's it wouldn't start. It would turn over, but not start. 

At that point I knew it wasn't ceased, because of the knocking problem, it had to be the carb, or like I stated before, excessive carbon deposits on the valves/headers/etc. I was getting so ticked off at it I decided to take it apart this winter and see what the heck was going on. I never took an engine apart, but my dad was on the verge of thowing it out. So what the heck I thought, even if I do screw something up, it's not like we were goin to keep it. When it was relitivetaly new, we had to take the carb in to be adjusted, mabe the dude screwed something up after that??? I'm still pecking around it, trying to figure out what is wrong with it. 

I'm going to take a look at the carb this afternoon and see what's going on there. Thanks again for all of your help!!!
bsman


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## bsman (Jan 22, 2006)

took apart the carb and everything looks normal, cleaned it up real well. After that, I took off the sump, and started to look around. The [email protected]#$ govenor fell off and had to fish it out with a clotheshangar. I came to a conclusion of the main shaft was rubbing on or hitting the camshaft which is directly behind it. Now all I need to know is why?? What's offbalance or even worse, bent. Can you guys help me out???? Thanks a lot, bsman


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## bugman (Aug 12, 2004)

it could have been off balance, you could try the parts back and forth, to see about how loose they are, the governors replaceable.does the cam look bent, how about the crank? i would take it all the way apart, and check measurements. oh and blue smoke is oil.


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## bsman (Jan 22, 2006)

Alright, but what would I measure, and were would I find the correct measurments?? B&S.com??   I would have to measure the connector rods, crankshaft, camshaft, etc. Thanx for your help.


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## scrench (Dec 8, 2004)

just move it with your hand if it has play in it then there is your knock "connector rods"


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## bsman (Jan 22, 2006)

Alright, i'll give that a try. Thanks Again.


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## bsman (Jan 22, 2006)

Nothings loose, everything nice 'n tight. Could it be off balance because of timing or something related to that??


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## bugman (Aug 12, 2004)

it could have been the governor, come to think of it, plopping around in there. the timing is straight forward, line up the marks.


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## bsman (Jan 22, 2006)

The governor could have been, but i'm still trying to find out what the crank was hitting to have such a worn mark. I took one of those dentists mirrors and suck it behind the crank to see if it was in fact hitting on the cam shaft, but I couldn't really tell. I'll post a picture of the nice scrape job it's been working on tonight.

One more thing, if the engine was bouncing around, could this have caused something to skip, and not be properly timed??

All your help is greatly appreciated!!

Adios Amigos


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## bugman (Aug 12, 2004)

nope, its just straight forward timing, the only timing thats done is with the cam, and the crank, the marks just get lined up, and the timing can't jump internally, now the timing of the flywheel can be messed up, its a little safety deal, the flywheel key, it could have gotten sheared, its just a little rectangle of alluminum, and cheap to replace.


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## bsman (Jan 22, 2006)

so this would cause it not to start/run???


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## bsman (Jan 22, 2006)

so this would cause it not to start/run???


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## bugman (Aug 12, 2004)

a sheared key, throws off the timing of the flywheel, may get spark, but it would be off timing.


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