Other Sears Craftsman Garden Tractor

[jcdammeyer]

Well it's back together. Still not sure about the balance rods. One video on Youtube suggested the bevel should point towards the crank weights. As if to clear the machining. Except there's nothing to clear. And with it up to capture oil splashes and hold them till it runs down in between makes way more sense.

In pushing in the new oil seals I noticed what may either be casting lines or a bunch of cracks. And I spotted what may be a crack in the bottom pan. Doesn't seek to go all the way through thought. So this may all be wasted money other than the entertainment of rebuilding an engine.

We'll see in a couple of days. The RTV gasket material has to cure first before I tighten down the valve cover gasket. Still some cleaning on the main tractor frame. Probably won't get it together until the weekend since so much other stuff going on this week.

 

[YotaBota]

Here's hoping for the best.

 

[jcdammeyer]

Here's hoping for the best.

It will be a few days now I think before I get it back together. Lots happening this week.

 

[jcdammeyer]

I'm pretty well ready to mount the engine so I thought I'd finish the other small projects first. When I had it up on the engine hoist I noticed that the Right Front steering pivot plastic bushing had risen up out of the hole and there was clean metal against metal visible. I was able to push it back down but couldn't figure out how to keep it there as is.

Well finally found the bushing on an obscure place in the parts manual. It was missing. How does something like that go missing. Very strange. Even stranger is in addition to the part number the dimensions were in the description. True, it wasn't 0.125" diameter with a 0.72" hole. Really 1.25". Turns out the hole dimension was a tad small and I had to remove another 0.020" on the part I turned on the lathe.



And installed.

Should have less wobble in the front end I'm guessing. Don't know yet.

And with a bit of filler, primer and paint the repair part for the PTO is also ready to go in.

 

[DavidR8]

Well sorted!

 

[Susquatch]

Well finally found the bushing on an obscure place in the parts manual. It was missing. How does something like that go missing.

My older Mower had a grub screw in that bushing to keep it on. I remember cuz I lost mine too.

 

[jcdammeyer]

You'd think they would have put it on the drawing right above #30 but instead #20 is way over by the arm. That's why I didn't spot it right away. I just figured there should be a bushing there. Having the measurements on the parts list just made it easier rather than wing it.

 

[jcdammeyer]

So it runs. But surges. Went through the governor adjustment with no luck. More research suggests it's a carburetor flow problem. Pulled it apart today and there is some gunk in it but not so much that it should not work better.
In either case now in the cleaning solution and one of these ordered.


It's prettier than the old one.

 

[YotaBota]

A quick search on "b&s engine surging" on youtube gives some possible fixes.

I'm trying to find the one that fixed my engine, smog carbs have no mix adjustment and that is the orifice that was plugged on mine. I'll keep looking.

 

[jcdammeyer]

A quick search on "b&s engine surging" on youtube gives some possible fixes.

I'm trying to find the one that fixed my engine, smog carbs have no mix adjustment and that is the orifice that was plugged on mine. I'll keep looking.

Thanks. Clearly the shut down solonoid is screwed. When power is applied to it the plunger moves out which looks like it blocks the intake hole for the main venturi. Now this one was seized in the down position so other than shutting off the fuel supply in the case of a person ejected from the seat I can't see it causing the surging. I had to pry it loose with a screwdriver.

Now there was other gunk inside the carb body. I've cleaned it with varsol and throttle body cleaner but if you think there is a small orifice that might be blocked then I'll toss the now reasonably clean one into the ultrasonic cleaner with the proper carb clean.

I could have ordered a new replacement carb of unknown quality for $30 from amazon.ca but no idea if any of the jets are the correct size. So instead I ordered the electrical valve for $19. Even a gasket kit for this thing is $60. Crazy. I'm going to try and reuse the gaskets for now. The all came off intact and in good shape.

So maybe it was just the crud inside the carb that was the issue. I'll know after Wednesday when the new fuel filter, air filter and solonoid arrive.

 

[Chicken lights]

Thanks. Clearly the shut down solonoid is screwed. When power is applied to it the plunger moves out which looks like it blocks the intake hole for the main venturi. Now this one was seized in the down position so other than shutting off the fuel supply in the case of a person ejected from the seat I can't see it causing the surging. I had to pry it loose with a screwdriver.

Now there was other gunk inside the carb body. I've cleaned it with varsol and throttle body cleaner but if you think there is a small orifice that might be blocked then I'll toss the now reasonably clean one into the ultrasonic cleaner with the proper carb clean.

I could have ordered a new replacement carb of unknown quality for $30 from amazon.ca but no idea if any of the jets are the correct size. So instead I ordered the electrical valve for $19. Even a gasket kit for this thing is $60. Crazy. I'm going to try and reuse the gaskets for now. The all came off intact and in good shape.

So maybe it was just the crud inside the carb that was the issue. I'll know after Wednesday when the new fuel filter, air filter and solonoid arrive.

I don’t know how else to say it- “tag wire” (wire for tags? ) was the right size to run through small engine carb ports

 

[jcdammeyer]

The cam shaft kit came with a whole bunch of different size sire/brushes. Forgot about those.

 

[Susquatch]

I could have ordered a new replacement carb of unknown quality for $30 from amazon.ca but no idea if any of the jets are the correct size.

If the carb is for that general size of engine (small if), and if the quality is ok (big if), the jets should be ok. In general, a carb doesnt know what size engine its on. It only knows how open the throttle is, how much choke is applied, and how much air is flowing through it. So replacing the carb when all else fails isn't a bad idea.

 

[YotaBota]

IIRC the solenoid is there to prevent fuel flow when the engine is shut off. As the fuel tank is higher than the carb if the fuel flow isn't stopped when the engine is shut off fuel can fill the cylinder. Then you get a hydraulic when you try to start it and it can blow the engine if the plug fires, this is what happened to the engine I have.

 

[Susquatch]

IIRC the solenoid is there to prevent fuel flow when the engine is shut off. As the fuel tank is higher than the carb if the fuel flow isn't stopped when the engine is shut off fuel can fill the cylinder. Then you get a hydraulic when you try to start it and it can blow the engine if the plug fires, this is what happened to the engine I have.

Usually, that's not what happens. Gasoline is like hydraulic oil and water. It's incompressible. If you crank the engine the incompressible fluid cannot compress and something has to give. That's why they call it "hydraulic lock".

It's also unlikely it could ignite as it needs to have air to burn. In fact, there are limits both rich and lean beyond which it won't ignite.

I think it's more likely that it seeped past the rings and ignited in the crankcase. Of course, hydraulic lock without any need for a spark would destroy it too.

This is also why you shouldn't try to start an engine that has fallen in the water. If the cylinder fills with water, you can destroy it just turning it over. Better to drain it all out first.

My experience with B&S engines is that they self destruct after a given number of hours. Usually after the Chrome on the cylinder walls wears through. But they have lots of other weaknesses if that holds up for whatever reason.

 

[jcdammeyer]

IIRC the solenoid is there to prevent fuel flow when the engine is shut off. As the fuel tank is higher than the carb if the fuel flow isn't stopped when the engine is shut off fuel can fill the cylinder. Then you get a hydraulic when you try to start it and it can blow the engine if the plug fires, this is what happened to the engine I have.

Ah. That explains it. Plunger should be spring loaded against the inlet hole then. Power applied and plunger should pull in to then allow fule to fill the float bowel which I thought was there to prevent fuel from flowing if the engine isn't running.

The carb is soaking in the cleaning fluid now. I've washed the inlet and outlet pipes. The float and float assembly have all been cleaned. If all goes well when put back together should theoretically not surge...

 

[140mower]

Ah. That explains it. Plunger should be spring loaded against the inlet hole then. Power applied and plunger should pull in to then allow fule to fill the float bowel which I thought was there to prevent fuel from flowing if the engine isn't running.

The carb is soaking in the cleaning fluid now. I've washed the inlet and outlet pipes. The float and float assembly have all been cleaned. If all goes well when put back together should theoretically not surge...

If you can, remove the jet(s) and the emulsion tube(s) just above them and check that all the little holes are clear. I pull a wire out of a wire brush and push it through the cross holes in the emulsion tube to clear them. I am almost always successful in bringing back the dead......
Premium fuel is recommended to avoid the issues with using ethenal fuels in engines that might sit for months at a time.

 

[jcdammeyer]

If you can, remove the jet(s) and the emulsion tube(s) just above them and check that all the little holes are clear. I pull a wire out of a wire brush and push it through the cross holes in the emulsion tube to clear them. I am almost always successful in bringing back the dead......
Premium fuel is recommended to avoid the issues with using ethenal fuels in engines that might sit for months at a time.

I will follow everyone's instructions here. The last carburettor I rebuilt was an SU type for my MGB.

 

[YotaBota]

Rather than buy a new solenoid I put a ball valve in the fuel line and just try to remember to shut the fuel off after mowing the lawn.

 

[jcdammeyer]

Rather than buy a new solenoid I put a ball valve in the fuel line and just try to remember to shut the fuel off after mowing the lawn.

Too late... It's already been shipped. I currently have the original sitting about half way into a container of the rust removal liquid. Another hour or so and I'll see if it moves more freely.