8 HP Briggs and Stratton problems with surging and almost dieing

[cpurvis]

I recently just got a brush mower with a 8hp Briggs industrial plus horrizontal shaft . Some one had tried to get it running before I got it and I'm not sure what they had messed with . I cleaned the tank, replaced the petcock, new fuel lines , air filter , new fuel pump . Cleaned the carb by taking it apart and dunking it then spraying with carb cleaner and compressed air . I found the previous person didn't remove the jets because they came out hard . So I got it running but it hunts and surges . Almost dieing and small backfire at times . I checked for intake leaks with carb cleaner but nothing seems to stand out but it's also running bad enough that I'm not sure you could tell .I'm kinda running out of ideas . Thanks for any input

Hunting or surging, especially under no load can be caused by a lean mixture. If your carb has an adjustable jet, try opening it, 1/8 turn at a time until the surging goes away.

If that doesn't do it, or you have no adjustable jet, you'll have to clean the carb again, this time rodding out all the passages you can get to, with fine wire, torch tip cleaners or whatever you can make do. Just today, I had to fix (again) a 6 hp Briggs engine that had the same problem as yours. All I used was a paper clip, torch tip cleaner and compressed air of the high pressure (80 psi) variety. Sometimes soaking and spray cleaners just won't do it.

 

[Vortec325]

Yup I've checked everything is hooked up right . It pumps about a 18oz water bottle full in 30 seconds by just pulling it over . This carb is non adjustable . I've cleaned it with a paper clip then dunked and sprayed probably 3 times now . I put a new plug in to rule that out and after some running it is blacker than the ace of spades and it blows black smoke when it has its issues

 

[Vortec325]

 

[cpurvis]

This carb is non adjustable . I've cleaned it with a paper clip then dunked and sprayed probably 3 times now . I put a new plug in to rule that out and after some running it is blacker than the ace of spades and it blows black smoke when it has its issues

Regardless of what you've done to the carburetor, it isn't fixed. Consider replacing it with a new one.

 

[Vortec325]

I've considered replacing the carb but it's a little over $100 and didn't want to spend that much on a old motor and not have that be the issue

 

[bertsmobile1]

Well if it ain't leaking air and it ain't got a blockage in the fuel tank and it ain't got a blocked fuel line and it is surging then the carb ain't letting enough fuel through.
The only other possibility is a leaking head gasket but you will hear see & small that.

Take the float bowl off turn the fuel on and work the float with your finger checking for a good fuel flow each and every time you let the float drop.

 

[Vortec325]

Well I do have oil on the top end but I can't find where it's coming out of . I just thought it was because the plug loosened up and I don't notice . I'll check the float but it's kinda a bitch because I got a fuel pump on it and it don't pump unless I'm yanking it over

 

[Boudreaux In Eunice La.]

Ok try this this first. Take the breather off. It is on the side of the engine and look at the valves while you are spinning it over. Both springs should be moving back and forth........... The gasket most of the times 95 % stays intact if you are careful.

I f they are doing like they should then it is time to take the flywheel off and check the key. On your style cutter which reminds me of the old Yazoo cutters really don't shear keys because it is a belt driven type machine as in a rider mower.

It is possible though to shear a key on a back fire scenario...... Or a flywhell that has not been tightened down enough.

Post the code number also. It's the numbers after the type #'s

 

[Vortec325]

Code #9606121c

I've already looked and the valves are working . I guess I'll take the flywheel off and have a look

 

[Boudreaux In Eunice La.]

Ok that is a 1996 model engine. That's the date it was made not sold. No telling when it was sold. If a flywheel key is partailly sheared it can backfire.

Advanced is a good thing cause we used to build those engines for racing Karts. 5 HP mostly in the modified class and super stock.

How do know the valves are working ? You took the breather off of the block earlier ?

Let us know Mon Ami ~!~!