Need some help with a 6.75 HP B&S

Allergic2Grass

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• Aug 16, 2019 / Need some help with a 6.75 HP B&S

• #1

126T02-0675 B2

Ive taken this thing apart around 4 times now trying to figure this out. Need some suggestions.

To start, im the third person attempting to fix this mower.

First person cleaned the carb, still no dice.
Second person checked compression and said there wasnt any, ended up getting an injury and wasnt able to work on it further.

Now that i have it, so far ive checked the valves. There was a ton of carbon and the valve seat ring on the top one was stuck out. Put the ring back and sprayed some penetrating oil to help it move better. Put it back together and it started first pull. But it dies after a minute and it sounds weak.

Did some more googling and watching and low and behold i put the thermostat on wrong(looped it, thanks Taryl). Still no dice because the thermostat is bad, it doesnt spring back like it should.

Does it sound like anything else other than a bad thermostat that i should be checking?


Thanks.

 

R

Romore

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• Aug 16, 2019 / Need some help with a 6.75 HP B&S

• #2

The engine has been overheated for the seat to come loose. Did you stake it in place so it stays put? Did you check the clearances? Is the head properly torqued with a new gasket?

 

Allergic2Grass

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• Aug 16, 2019 / Need some help with a 6.75 HP B&S

• #3

Romore said:

The engine has been overheated for the seat to come loose. Did you stake it in place so it stays put? Did you check the clearances? Is the head properly torqued with a new gasket?

Click to expand...

I didnt stake it in place. Should i go ahead and do it if it hasnt coming out thus far? Or is it bound to happen once/if im able to get it operating?

Clearances, not yet, will check this weekend.

No new gasket, didnt torque it to any specs:laughing:

 

Scrubcadet10

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• Aug 16, 2019 / Need some help with a 6.75 HP B&S

• #4

Kill 2 birds with a stone,
Take the head off, stake the valve seat, install new gasket, torque head bolts to 190 inch pounds.

 

cpurvis

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• Aug 17, 2019 / Need some help with a 6.75 HP B&S

• #5

Thermostat? What thermostat?

 

Scrubcadet10

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• Aug 17, 2019 / Need some help with a 6.75 HP B&S

• #6

I believe this model has the Auto Choke, cpurvis.
Which uses - a thermostat on the muffler. Taryl has a video on it.

 

Allergic2Grass

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• Aug 18, 2019 / Need some help with a 6.75 HP B&S

• #7

Yeah it's part of the auto choke system.

Got a mower with a busted deck that I'll use as a project ( brush cutter) with the same engine.

Swapped the thermostat and it ran longer,but died. Took off carb and the float wasnt leveled. Swapped the carb from donor and it ran normally.

Now that that's out the way I'll still clean the carbon and check the valves and stake the seats. I want it all to be as good as I can get it before I return. Since I'm doing this for free it'll have to wait till next week. I'll update when I can.


Thanks y'all.

 

Allergic2Grass

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• Sep 1, 2019 / Need some help with a 6.75 HP B&S

• #8

Scrubcadet10 said:

Kill 2 birds with a stone,
Take the head off, stake the valve seat, install new gasket, torque head bolts to 190 inch pounds.

Click to expand...

Had to do some brake work and finally got a torque wrench.Lets just say i probably put the nuts around 80ft lb:laughing: whoops.

Got this thing taken apart yet again. Checking the valves...the intake valve i can a .011 feeler in it, but not .012, specs say .005/.007. Exhaust is fine. Im probably doing something wrong, but how can it be this short? Engine is TDC. Never taken it out, as far as i know the other folks didnt either.

 

Scrubcadet10

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• Sep 1, 2019 / Need some help with a 6.75 HP B&S

• #9

Are you checking the intake valve on exhaust stroke?
I normally check the intake valve when the exhaust valve is open and exhaust when intake valve fully open.

 

cpurvis

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• Sep 1, 2019 / Need some help with a 6.75 HP B&S

• #10

The valve seat is probably not seated correctly. That will hold the valve up, creating excessive clearance.