Tuesday, 6 September 2016

Lee's Mk II .177 Innova

Lee's .177 Innova

It would appear that i'm getting myself a bit of a rep for fixing up old Innova's for people and each time i find something new that i've not come across before. Lee got in touch with me saying that he could not get any power out of his .177 MkII Innova after trying to follow some of my guidelines, i offered to take a look at it and a few days later a rather splendid looking example of an Innova came through the post.

exciting, what's in the box.

Oh, it's an Innova in bits.

It was in many bits where he had tried to fix it and a few of the parts were damaged through wear and tear with the odd part missing, the arms of the front sight post had snapped off

This is not good, but will do for now.

 and the circlip for holding the pump arm pin was missing. 

I'm gonna have to make a circlip for this.

Originally this was Lee's rifle and he had let a friend have it and from then on it had passed on through a few other people till it came back to Lee, it would appear that a few of these people have been messing about with it in a not to kind of manner since then.

Still the same Innova

Lets face it  the Innova is mostly polymer/plastic and after 25 odd years things are going to wear out, get stressed, chip and snap off, work loose and bend. Especially if a few off those people think it's a cool idea to ramp the power up, when really it will recieve a hell of a lot less sress if you only pump it 8/9 times to get 12 ft/lb and not 15 times to get 16 ft/lb. 

The tension on that spring will decide if it's under power, just leagal, or over the top.

It's certainly not the same gun Lee remembers from his youth, but with a bit of TLC and some crafty bodging it could be pretty damded close

There you go, MkII Innova.

MkII's have the safety catch.

MkII's also have a butt pad.

The power was no problem to fix as i adjusted the pump rod to the maximum reach. oiled the pump head, and with five pumps it was letting out a satisfyingly loud crack, however i could still put in 15 pumps without the blow off valve kicking in. I also left three pumps of air in the rifle overnight which had leaked out come the morning time, so looks like a good old fashioned overhaul is required.

When i stripped it again i noticed that oil had leaked past the exhaust valve body O ring so that one needed replacing, 

Yep, had to replace some O rings here.

i also stripped the valve and replaced the O ring between the Valve and firing pin housings thinking that that could be the cause of the slow leak. Everything else inside looked fine which was what Lee had done himself, there was still a leak on putting it back together but much, much slower.

Seeing as i had a set of firing pin seals i removed the firing pin,

Bolt assembly.

so replacing the seals would let me know that all the power from pumping was hitting behind the pellets.
New seals fitted.

Using a pipe wench, 10 and 14 mm spanners, and some pliers i unscrewed the housing and pump head off the blow off valve, 

If you have to do this it's usually only the once, after that finger adjustment is all that's needed

out came the spring  and valve pin was removed easily with a small pair of needle nose pliers. 

Someone else has been messing about here, looks like somethings missing.

Inside the valve housing was a brass sleeve which screwed into the inner wall and held the blow off valve seal in place tightly, lining up with the underside of the pumphead there were two knotches so i could cut and shape a flat bit of metal to act as a screwdriver. It all came out with years of crap and oil and gunk but looked in good knick all the same, and sure enough when it went back together it worked which in my opinon was a result, praise be Saint Jezzer.
Down to all the basic bits

The head of the valve pin has a cup shape which looks like it would seat a 4.5 mm ball bearing,

Reckon a ball bearing should fit in there, but some sad hat must of lost it way back.

so i added a ball bearing as it would seat better against the blow off seal and the air pressure would blow off at pretty much the same each time.

Now that looks like it should work better.

Putting the pump arm back together now left me with getting the the blow off valve to release around 11.5 ft/lb, minute adjustments on the spring pressure where needed.First adjust the tension on the blow off valve spring,

!001 minute adjustments.

then adjust the slack on the other end of the valve

1001 minute corrections

 198 mm seems the ideal length for the whole pump rod assembly.

I really couldn't be arsed to check this a 1001 times.

If it's too short the the pump arm doesn't lock in place and hangs down,
So sometimes this happened.

if its close to right then it will lock in place.
But mostly not.

It sort of went too low, too low , too low, shit too high, still too high all the first afternoon.

Why did it take so long that afternoon?

But for some reason on the second afternoon it took no time at all, sure had me puzzled.

2nd afternoon took no time at all.

So there you go, one MkII Innova fixed to the best of my abilities. To get it nearer perfect Lee will have to invest in a new front sight unit and a stock screw and brass collar as they are fairly worn, but for now i got the stock on tight with the use of a small washer.

With the aid of a little washer the action sat firmly in the stock.

Remember boys and girls, old Innova's never die they just get sent to me to bodge, fix, and generally get loving treatment.


Best wishes, Wing Commander Sir Nigel Tetlington/Smythe. 

 P.S. Remember to remove all and any burrs from the inside of the compression tube as not only do they ruin seals, but they can make the pump rod awkward to to remove and replace.

It's boring work but it saves you so much hassle in the long run.



  1. Hi there
    I'm trying to fix an issue on my Sharp. I think it's missing part of the trigger. Do you have any pictures of the trigger setup?

  2. Fnd the series of blogs under SHARP 22. a Restoration Project I did 18 months back, there is an entry on the Trigger and sear.