Craftsman Briggs and Straton 6.75 refuses to prim

P

PopIggy

Member
Hi all,
I have an old B+S 6.75 walk behind mower. It refuses to prime the carb. I installed a new air filter plate with two gaskets and a new carb.
She will start and run great with a squirt of starter fluid, but it will not prime. I'm now going crazy.

Many Thanks to all.

Popiggy
 
This is why I make up a wedge gasket using two gaskets to apply extra pressure at the point of non contact. It is because the filter base is warped.
 

125K02-0658-E1​

Install one gasket and tighten the screws. Now remove the base, remove gasket, and look at the impression left. It will show you where the added pressure needs to added with the wedge gasket that is applied opposite side on the missing impression.
 
Why spend $34 dollars when a couple aftermarket gaskets cost less than a $1 along a drop of wood glue to hold two together until the screws are tighten. Now gaskets do retail for $3 each. This setup works very well when properly done.

So far in the last 17 yrs I only replaced a couple of these bases and that was due to other damage.

But of the use of a backbone razor blade might be too difficult for some to use.
 
just thinking about this thread made me think for a second. Are we treating the problem or the symptoms? The problem is that the engine will not start on primer. It is possible that something else is going on like a cracked plastic intake manifold, or a loose head sucking a little air, or tight valves. My Toro with about the same engine won't start with 3X primes since new. It takes five or six, then it starts. Also, I fought with it many times when hot starting until I learned the best way to start a small engine. My other half complained about the same until I showed her the best way to start it - now she starts it hot or cold on the first pull each time. Lots of these engines are designed to run lean. They are not like small engines when we were kids that had both an adjustable idle and high speed needle to get the optimal mixture. Pull the engine comfortably until drag is felt, then pull hard. If that happens with the rope almost all the way out, let it back in and pull.
 
StarTech said:
Why spend $34 dollars when a couple aftermarket gaskets cost less than a $1 along a drop of wood glue to hold two together until the screws are tighten. Now gaskets do retail for $3 each. This setup works very well when properly done.

So far in the last 17 yrs I only replaced a couple of these bases and that was due to other damage.

But of the use of a backbone razor blade might be too difficult for some to use.
Click to expand...
Sometimes two gaskets doesn’t do it, and still will not prime. You can buy a new base for only about $15-$20 dollars.
 
Tiger Small Engine said:
Sometimes two gaskets doesn’t do it, and still will not prime. You can buy a new base for only about $15-$20 dollars.
Click to expand...
My lord guys use what God gave you; your eyes and brain. And hopefully you know what a wedge is that is if your schooling was any good.

You don't simple put two gaskets [doubled up] on. You got to look the impression when a single gasket is installed and then make up a wedge shaped gasket using a second gasket that is shaved to make it thinner on two ends thus applying more pressure at the point of non contact with the thicker part. Of course you apply this second gasket on the backside opposite of the air channel. Sometimes I only need less than half of the second gasket.Then you just snug the screws and don't go hog wild tightening them as this just warps the base.

As I said I only replaced two bases in 17 yrs. All others have been saved using this technique. One was from a tech tightening the screws so much it busted the base and the other was from fire damage.

But of course some are too stubborn to even try this technique. They rather install a new part that they make more $$$ on.
 
You must log in or register to reply here.
Back
Top