Briggs and Stratton 6.75 engine getting caught up at TDC?

[itsgalf]

Hello all, I took in a guy's lawnmower to try to get it running. It's a Troy-Bilt mower with a 6.75 B&S engine.
Model: 126T02-0675-B2

The guy said he tried to follow a video about taking apart the carburetor so that he could get it running. But then he couldn't figure out how to get it all back together confused2. So I took it for him and got the carb together (He had the gasket for the bowl bolt just sitting inside the bowl - I think he was over his head). Anyways, just waiting on a new carb overhaul kit (need a couple gaskets).

In the meantime, I tried to turn it over with the pull-rope and the engine started to hang up. Never encountered that before. I took out the spark plug and looked inside while turning the flywheel and it's getting hung when the piston is at TDC.

I don't want to break into the engine at the moment (the guy is cheap and probably doesn't want to pay for that kind of repair), and I have very little experience breaking into engines.

Could someone point me in the right direction? Possibly normal and needs to be broken in? He used to use the mower and probably beat up on the thing
FYI, the guy doesn't seem like he takes care of his machinery, so is it possible something got bent?

Also, here's a picture of what I found under the drive pulley cover just for sh*ts and giggles


EDIT: Here's a video of what I'm talking about, I think you all should be able to load it.

https://photos.app.goo.gl/VZ4c1oKq3KQfCYZs9


Thanks,
- Marco

 

[Russ2251]

Is the coil properly gapped @ .010" ?

 

[itsgalf]

I checked that it was gapped at 0.10", but I don't think I gave it a full turn to make sure it didn't rub all the way around. I'll have to double-check in the morning.

But it really is a hard stop/clunk that requires quite a bit of torque to get past and happens right at TDC

 

[Boudreaux In Eunice La.]

Galf I think you may have something going on in the inside that you don't want to see...... Does it or shall I say can the engine be turned completly 2 or 3 times ????

If the pull rope can't do it try turning it with the blade.... Take the plug out before you do that though..... Safety......

Let us know Mon Ami ~!~!

 

[Boudreaux In Eunice La.]

I just saw the video... Looks like maybe the governor is shot and causing a bind or the rod is broke....... If it's the gov you might be in good shape......

Otherwise you have a very good parts engine if the owner gives it to you for your time in it.......

 

[itsgalf]

So I got a little time to take it apart. I took the engine off the deck and disassembled at the crankcase. So with the governor not in the picture, it is still getting caught up at TDC. I had something else to attend to so didn't get further. Guess I'll have to break into the cylinder head sometime.

 

[Boudreaux In Eunice La.]

Well the rod is not broke...... It could be bent though, or the crank is bent..... I have seen that happen toooo many times....

Yes take the head off and then check the bore for scoring and such.... You could have a piece of a spark plug inside of there stopping the rotation.......If that's the case then put it back together if the bore is not messed up and you will have a great engine....

If a piece of plug is not in the bore then go ahead and take the flywheel off and pull the crank.... Bring it to a buddy that has a lathe and have him chuck it up to see if it;s out of whack / bent ........

If not then it's the piston rod bent.....

I have used parts for your engine................

Let us know Mon Ami ~!~!

 

[sgkent]

or a piece of the carb / gasket from when he was screwing with it. He might be telling you the whole story.

 

[itsgalf]

Just an update - decided to get back to it today.

Removed the cylinder head and found something crushed up stuck to the cylinder head. I think it's old grass carcass.
So cleaned it up best I could and put it all back together. Got it running again. Didn't have any "spare parts" afterwards, so that's always good.

Question - There's some burn marks or carbon deposits or something on the top of the cylinder near the valves. Is that normal? (first time breaking into an engine) Or is that an indication of something?

 

[Russ2251]

I think it's old grass carcass.

...Or a small mammal.