125 won't start
 

I have a 125 that I can not get to start. It will turn over and backfire through the carburetor. I set the points as J-mech described in his post but I still cannot get it to start. It will not even start on starting fluid. Any ideas or suggestions would be appreciated. Thanks Bill

Sounds like a stuck intake valve. Download the service manual for that series or the k301 manual. You can take the valve cover off to see if it's stuck open. Try not to use too much starting fluid or you could make things worse.

ok i will have to do that. I have a manual already that my father-in-law gave me. He used to have a 127 years ago.

I just read some of your posts. You bought it not running. This seems like the most likely cause as assuming it had been sitting for a while? There may obviously be more wrong but let's get it running first. Hope it's not a smoker! Good luck!

no I bought the 125 running. It has always been hard to start. usually it will start eventually after cranking for a while. The 129 I bought not running have not messed with it yet.

I think Alvy is correct, but I'd pull the head along with the valve cover. That's where your headed anyway.

Check the compression. If it has an acr it should have about 50 to 60 psi of compression. Also make sure it's timed right.

He said he already set the timing.

Since it has an ACR, it's going to make low compression. Yeah, your numbers are correct. Sooooooo....... how is he going to know if the valve is sticking? Pulling the head in this case is the best option. :bash2:

Sorry, didn't catch that he already timed it

remove the spark plug and blow a little air in the hole.Put your hand by the muffler,if you feel air it is open,rotate the motor until you don't feel it anymore ,if you still do it is stuck open.

That's a good test, Lew. I do that all the time.

Check for air movement out the carb too though, since we think it's an intake valve. :beerchug:

Or not seating good. This also applies for intake and can be tested with a leak down tester,a blow gun that has a tip that seals the plugs diameter, or the quarters inch quick connecter found on some compression adapters like the one I have if the coupler is the same size and type.

I pulled the valve cover off this afternoon. It appears that both valves are going up and down. I pulled the spark plug and I feel air coming out of the spark plug hole when I crank the engine.

I moved this to the Kohler section for you. Time for the Kohler masters to do what they do best. :beerchug:

The valves going up and down doesn't mean that they are seating. Did you adjust them while you were in there? Do you still have the cover off?

Time to pull the head, like I suggested in post #6. :beerchug:

that is my plan for tomorrow I pulled the plug and it was carboned up pretty bad and it was also the wrong plug

faulty ignition components can give you the effect that timing is off while it is set correctly.

what plug was in it? it should be a champion H10c if your 125 has its correct 12hp kohler k301

it had a J8C champion that is what was in it when i got the cub.

Should have been fine. Near as I can tell the only difference is the reach. Heat is similar. It wasn't your problem, unless it was bad.

the J8 was a very common plug with almost all the Briggs engine years ago so everybody had one laying around. while it is the wrong plug they will run with it