Briggs 126m02

[rthacker7]

I have a Briggs 126M02-0298-B1 code 11090759 that I think I need a little help on. This is on a log splitter and has I would guess 20
hours on it. It has never started easily with 8 or 10 pumps on the primer to get it going.
Last fall it would not start and due to several hospital stays I had to let it set. Just getting back to it but its almost too cold
most of the time to get out and do alot.

It will prime , start and run until the prime burns off then quit. It will start and run on carburetor cleaner then quit. I have cleaned the carburetor
a couple of times and also changed out the jet (71) , just to be sure its clean. Just as a try I drilled out another jet to 62 I think and it
started and ran although quite rich. I found a problem where the needle and float wasn't letting but a few drops of fuel into the bowl so instead of
ordering repair parts I ordered an aftermarket carb. It does the same thing - prime, start and run until the prime burns off and quits.
Its not drawing fuel thru the emulsion tube running but will prime thru the tube.

I have taken the plastic intake off and found no cracks or leaks. Replaced plug and tried fresh fuel.
I'm starting to loose my way, any ideas would be appreciated.

[KE4AVB]

Double check the fuel into the carburetor bowl. You may have fuel line particles or trash blocking fuel flow or in the bowl plugging the jet at start-up. It doesn't take much on these jets.

I have cleaned the carburetor a couple of times and also changed out the jet (71) , just to be sure its clean. Just as a try I drilled out another jet to 62 I think and it started and ran although quite rich.

If you drilled out that 71 it would not get smaller and become a 62; it would increase in size instead. (Jets are sized hundredths mm.) Plus when resizing jets you only want increase in steps of .01mm or so only at a time to enrich a fuel mix and test. Once oversized only replacement is possible.

[rthacker7]

Forgot to say fuel line has been replaced with no trash found since. I know I went a lot on the jet as a test but it did prove I
could get fuel and run even if grossly rich. With a large jet one can actually see the fuel exit the emulsion tube while it is running.
I sorta expected to find a crack in the plastic intake tube but it holds a vacuum and the gasket seems to seal.

[sawman]

We have had several of these which had under torqued cylinder heads causing lack of vacuum. They couldn't pull in fuel on their own but would run by priming.

[KE4AVB]

Good thought. Thanks for sharing your experience with us.

I was thinking about the leak-down test but haven't mention it yet.

[rthacker7]

We have had several of these which had under torqued cylinder heads causing lack of vacuum. They couldn't pull in fuel on their own but would run by priming.

Very interesting, same symptom. Thought about a leak down test last night. Will check that out when it warms up a little.

[bluemower]

What is the valve clearance?

[Luffydog]

.004-.006 on both i think that is what it was before the page crashed and now it wont open back up. maybe someone else can help in a bit. i only saw it for like a second before it crashed. i hate the net,computers,phones........

[KE4AVB]

.004-.006 on both i think that is what it was before the page crashed and now it wont open back up. maybe someone else can help in a bit. i only saw it for like a second before it crashed. i hate the net,computers,phones........

Try again...Spec is as follows:

• Intake Valve (in) .005-.007
• Exhaust Valve (in) .007-.009

I don't think it be off much if any on a 20 hr machine; unless, something major has happen in the valve train.

[Luffydog]

thanks for the correct like i said only saw for a second then the page went blank.