IZH 46M pumping lever popping off

[seamaster]

My 46M lever is not catching well. A few times, slightest bumping will make it jump back out.

What is the problem? Solution?

[Lenny]

Lubricate the catch mechanism on the pumping lever. It's a simple step that probably won't help, but should be tried before going to more complicated adjustment. I actually did the adjustment.

To adjust how tight the lever latches in, you need to adjust the aluminum piston. It is made from two parts that screw into each other and locked by a small screw (or screws, don't remember). You either have to unscrew them or screw them together a few positions (don't remember). Try either way until it will feel right. It's time consuming because you have to disassemble and reassemble piston mechanism to try it for every adjustment, until you get it right.

[seamaster]

That second part looks a whole afternoon of work.

The first part, is there a spring in that latch that might have gotten weaker?

[Lenny]

Yes there is a spring in the latch, but it's not easily accessible. You can check if the tension is there by pressing the latch with your finger. I doubt it's the spring.

I have two IZH-46M pistols. Few years ago the linkage on one of them broke. I wasn't able to locate the replacement part anywhere. Since this was on one with a better trigger, I took the linkage from my other pistol. After I reassembled it with replacement linkage, I noticed the lever was barely latching, didn't feel like it used to. Somehow I figured out how to adjust it.

There aren't any difficult steps in this, only a lot of steps. If you ever replaced piston seal, you already did most of these steps.

[seamaster]

Lenny, I don’t see any adjustable screw on the diagram
https://images.squarespace-cdn.com/cont ... rmat=1000w

51 attach to 54

Screw 27 tighten/ loosen piston? I don’t see how THAT screw would do to piston tension besides holding 54 and 6 from going apart.

Which adjustable screw are you talking about?

Screw 54 in and out of 6 to adjust lever tension?

That is how you adjust 46M velocity, too?

[Lenny]

Part 54 turns into Part 6. That's the adjustment.
Part 27 is the screw that locks the adjustment.
In my initial instructions "screw" was used as a verb.

I also thought this adjustment is to adjust the velocity (pressure in the cylinder). I no longer think so.

[brent375hh]

Are you just saying that your lever won't stay up, and drops down too easy?
If so, replace spring 45 with something a little stiffer, or add a spacer for preload.

Spring 45 pushes on the plunger latch 44 that cams the lever up into the tube. Ignore me if your problem is something different.

[seamaster]

Changed spring45 with a left over LP10 velocity coil, latch is very strong now,but handle is still popping off if pistol is bumped ever slightly.

Screwed in piston lever, now popping handle is better, not completely resolved. But now it is shooting like a Daisy747, no longer a powerful 46“magnum”.

Pistol shoots like a pussy cat, quiet, very accurate, but weak, jagged pellet holes,

[seamaster]

Houston, we have a major malfunction.

In the process, adjusting handle with undue pressure, #51 broke in half.

Any prospective of finding replacement for #51?

Or is this the end of my 46M?

[Gwhite]

Ouch! for some reason, those are relatively brittle. The college team I help coach has managed to break a couple. Replacement parts have been unobtainium for a long time, and the pins that hold it the linkage together are swaged in place, so you need those as well.

I would contact Air Venturi (https://www.airventuri.com/av/) They are importing a new version (AV-46M), which means parts should be available again. I think at one time, they also had a number of dead ones they could cannibalize for parts.

[brent375hh]

I am curious. Did you attempt to increase your compression to the point of component failure?

If so, I didn't realize that was an option. Sorry about your linkage.

[Lenny]

Houston, we have a major malfunction.

In the process, adjusting handle with undue pressure, #51 broke in half.

Any prospective of finding replacement for #51?

Or is this the end of my 46M?

That's what happened to my 46M and caused me to replace this part from another pistol, which led to adjustment I described.

[seamaster]

Mechanically, could it be spot welded together? Would it be strong enough?

Metal sleeve on the outside?

[seamaster]

Just doing some Richard Feynman deductive inquiry into my "Houston, this is an obvious major malfunction" problem.

https://images.squarespace-cdn.com/cont ... ormat=750w

That 51 bar on 46M is linear-curved-linear, but on the pistol diagram on top (46, not 46M) it is a straight bar. I think that circular bend on 46M must have weakened, that extra weakened circular bend must have pushed the handle closure downward, preventing it to full close at the end of pumping.

Just my deduction.

Mechanically, does that curved bar give you any advantage over a straight bar?
New AV-46 from Air Venturi has a straight bar or a curved bar?

Now, I just have to come up with an idea how to put those two broken halves together. Thinking about going to a hardware store, buy a large steel washer of same curvature as that curve on the bar. Cut the washer to fit, steel epoxy washer onto the broken halves. Damn the torpedo, hope it holds.

[-TT-]

New AV-46 from Air Venturi has a straight bar or a curved bar?

The AV-46M has a bar like the one in your linked diagram, it's straight on the ends and curves upward in the middle. The reason for the curve is so it doesn't contact the slot in compression tube as the piston moves rearward.

To me, it sounds like the piston was "bottoming out" which caused the pistol to resist being fully cocked. This also may have added stress on the compression link #51.

[seamaster]

Which slot on the compression tube are you referring to?

[-TT-]

Here are a couple of AV-46M photos for clarity:

The compression linkage, showing the "bend":

AV-46M-levers.jpg (54.16 KiB) Viewed 2434 times

And showing the clearance at the bend, as the pistol is cocked about halfway:

[seamaster]

Got it.

Any idea how to put those two halves together?

[-TT-]

Personally I'd look for a top notch precision welder and attempt to repair the part. No way would I attempt to epoxy something around the break.

When the part is together, I'd adjust your piston pusher inward enough so there was no chance the compression stroke is bottoming out. A dozen or two fps makes zero difference in performance to this pistol. Mine came detuned to heaven-knows-what spec (AV doesn't say) but apart from tearing ugly holes in low quality paper, it puts them there beautifully. I'll dial it up eventually maybe.

[Lenny]

IZH-46 had #51 as a straight bar. This is what is shown in the illustration above parts diagram. When this pistol was redesigned into IZH-46M with longer compression chamber, #51 had to be
made longer, but longer straight #51 would jam into the end of a slot during cycling. They had to put in that curve into #51 to clear the end of a slot.
That curve made #51 literally the weakest link. I suspect yours was already cracked which was the reason the lever was not locking in place.
There was no way to get #51 from anywhere. I searched for it, even asked the guy from Russia who sells IZH-46M parts on ebay. He said he will try to get someone to fabricate it, but nothing came out of it. European American Armory has a good supply of IZH-46M parts. They told me, there is no way for them to get that part because of the sanctions. They are aware of the demand for that part.
Hopefully with new importation of AV-46M parts availability will change. I am glad I bought two of these pistols, when they were $250. When I cycle the lever now, I try to do it more gently.