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Briggs 3.5hp horizontal shaft 091202-1231 E1-0105293A

Need a good way to remount the carb to engine block.

Heavy object knocked off the air filter housing, carb and fuel tank from engine block. 2 pics show the engine block and broken area. Has 1 good bolt hole at the top of carb mount area.
Tried low temp aluminum repair rods from harbor freight. Can't get enough heat into the aluminum block. Didn't work for me.

My ideas are below.

1.JB Weld carb to block using 1 good bolt hole.
2.Same as above using a paper carb gasket.

Question is how would you fix this?




Dotted rectangle area is the part that is broken off the block casting. Thanks in advance guys.

slomo

can you put a heli coil in the bottom hole?

Scrubcadet10 said:

can you put a heli coil in the bottom hole?

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Half or slightly more of the bottom hole is gone.

Other than taking it to a welding shop and have it TIG welded...... Probably cost more than it's worth.

slomo

Thinking about using JB Weld or a good fuel rated RTV sillycone. Basically gluing the carb to the engine block. Use the only good top bolt to gently hold the carb to the engine. Don't want to crank the torque on it as to make it sit off the engine slightly. Just as a backup so to say.

What do you guys think?

slomo

Could you tap the good portion of the hole, install a stud, then carb, then a nut.. Use the RTV as well so it won't have an intake leak..?

If you can get a drill to run square into the hole
Drill & tap for a solid insert and install it so it is just lower than the original surface
Build up the broken bit with what ever liquid mets / putty type goop you like. let it set then sand to a smooth flat surface.
And I woud do as Scrubby suggested and use a stud on the bad side.

Or if I could fit a small C-clamp or Visegrips LOL. The tank has a bolt to hold it on. Carb sits on tank.

What would McGyver do?

Here's some pics of the block area where the carb mounts.

Is it possible to find a carburetor that uses the two remaining tapped holes?

I hope I can explain this correctly, if that area is flat behind where that bolt goes thru could you make a plate that would fit behind where it is broken and tap a hole in the plate than use a longer bolt to go thru the broken area and thread into the replacement plate. You would have to make sure the plate would fit well enough to not shit when you tighten the bolt but once tightened it should stay put. Looking again you could also slip the broken piece between the the carb and your new plate to fill the space.

cpurvis said:

Is it possible to find a carburetor that uses the two remaining tapped holes?

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Thought about that already. Since the muffler is where it is and the carb has to bolt to the tank. But a carb from a normal push mower has a similar bolt pattern but not angled down. Probably not jetted for this smaller 3.5hp engine.

Going to call Permatex and JB Weld. Get expert advice on the best RTV adhesive and something to build up cast aluminum. I like olddiyer's idea of a flat plate with nuts and bolts. Might be doable with some metal whittling.

Need a good adhesive that possibly can be removed if I need to remove the carb later.

slomo

Slomo the problem getting the aluminum welding that is torched to work is that the aluminum is oxidize. In order to get it to melt requires more hear than you think to break through the oxidized layer. Most time by the time you time you do the aluminum underneath it is already liquid and just runs out. Tig welding works but even that is tricky on cast aluminum. If you really want to save the engine then get it Tig welded by an experienced aluminum welder.

Personally I never had any good luck with any of the JB Weld products.

Plus, some aluminum alloys are not weldable at all. Those that are weldable have to be welded with shielding gas, whether from a tank or through the electrode. JB Weld is nothing but epoxy with metal powder mixed in. Epoxy does not like heat.

I think the backing plate with the broken off piece fitted into the break (acting as a spacer; no welding or JB Weld needed) is the best bet. Even if it fails, you have damaged nothing.

Lets not get too exoteric here
1) it is an aluminium die casting alloy
So it will be either 12% Si or 7% Si + 4 % Cu.
A very weldable alloy

All Aluminium alloys are weldable, some are just a bit more difficult to weld than others
When you gas weld aluminium you dip stitch weld where when you see the top oxide start to float you dip the rod through the oxide then pull out, move a little further forward & repeat.
It is dead easy to do if you can get the right goggles that kill off the orange sodium flare.
Gas welding is actually the easiest to do because you do not have to clean the surface and if the casting is porous and full of oil like an engine crankcase the weld puddle will just lift the oil to the surface.
Electric welding of the same object will cause the oil to vapourise and blow molten aluminium everywhere .
Also aluminium oxide, like all metal oxides is an electrical resistor so it is hard to get a consistant arc which is why mig welders use an AC arc or square wave DC arc
Tig is better than mig on a casting because you end up with less thermal cracking and have a lot better control of the puddle size & heat .

I gas weld all aluminium and have no problems what so ever now that I have some of Kent's (https://www.youtube.com/user/tinmantech) lenses so I can see.
I also use a Dillon low pressure torch, now called DHC 2000 which I bought back in the 70's from Mr Dillion.

I held a 3650F propane torch to it for a full 2 minutes. Wasn't hot enough. That block just sucked the heat away like all get out.

I used a stainless wire brush on it. Sprayed carb cleaner to degrease it. The flame should of burnt off anything left. Guess I need a larger torch to throw more BTU's. Normal small propane torch didn't have enough beans.

slomo

slomo said:

I held a 3650F propane torch to it for a full 2 minutes. Wasn't hot enough. That block just sucked the heat away like all get out.

I used a stainless wire brush on it. Sprayed carb cleaner to degrease it. The flame should of burnt off anything left. Guess I need a larger torch to throw more BTU's. Normal small propane torch didn't have enough beans.

slomo

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Try the heat from this torch........

slomo said:

I held a 3650F propane torch to it for a full 2 minutes. Wasn't hot enough. That block just sucked the heat away like all get out.

I used a stainless wire brush on it. Sprayed carb cleaner to degrease it. The flame should of burnt off anything left. Guess I need a larger torch to throw more BTU's. Normal small propane torch didn't have enough beans.

slomo

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Preheat on that would need to be around 10 minutes minimum with the biggest burner you can lay your hands on.
I use an air:acetylene preheat torch.
I think you lot call them rose bud torches
You need to get the block to around 200 C before you think about building up or welding the broken bit back in
With that particular job probably would do a TIG if I could hold the broken bit in place good enough after the preheat.
Engineering shops sell thermal crayons that change colour which work really well for the pre heat .
If you are not a reasonable aluminium welder then take it to Wally the Welder with a bottle of his favourite booze .
Or if it is a learning process, then carry on.

When I first tried to weld aluminium I had a set of cobalt blue lenses but could never see the weld pool clear enough.
Then I got given one of Kents lenses and since then there has been no stopping me .
I got a couple of Kohlers with the famous crack and after blowing a few holes got them down pat.
Probably done 1/2 dozen of them
I like to do things in batched so there is a pile of cases with vent holes in the side where the counter weight has gone through.
Last run I did about 20 of them.
Kent does a line of low pressure torches aw well that are a fair bit cheaper than the DHC 2000, but I am used to it now so have no intention of changing.
The other nic thing with these types of guns is you can literally weld rust so they are magic on pressed decks, if not a bit on the slow side .

What OldDiyer said!

slomo said:

Here's some pics of the block area where the carb mounts.
View attachment 57475

View attachment 57476

View attachment 57477



View attachment 57479

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I'd like to know what the heavy object was. I would try fitting that piece that broke off back in place, then super-glue it to stay there. Then I would drill and tap (looking at this pic, I would be coming in from the right, with 6 - 10 small holes and screw it together. At that point the mounting hole, if damaged can be drilled and tapped. I just don't know if this engine is worth it.

Don't know if super goo has enough beans to hold that piece on under engine heat and vibes. Not enough meat to screw anything together. Broken part sits on a thin aluminum area.

slomo

IF you have clean access then yes you could pin it back then fill the cracks & smooth off