Put the prop on. Poke a popsicle stick into the exhaust port with the piston at BDC. Turn the prop, the piston will push up on the stick, hit the liner, and the liner will pop loose. If not, it’s really, Really, REALLY stuck.

Why would you heat your popsickle stick up first?

I thank you

The paint stripping guns from Home Depot work better for popsickle heating than the old Top Flite Monokote guns.  The one from Harbor Freight are junk.  They're only good for one pack of sticks.

On the up side, the sticks from Dollar General come in two sizes and they're 50 for a dollar.

Just if the humor passed over you

1) The line is usually stuck with gooey old oil.  Use a heat gun to free it up.  Use some thick gloves or rags
2) Put something soft like a popsicle stick in the port and use the piston to wedge up the liner.  Then grab the liner with a rag and pull it out.  The wood will not mar the liner. 

the blocked port as worked well for me good luck!

    Additionally, the aluminum expands much faster than the steel liner, giving it more clearance as it gets warmer. A good one will be a near interference fit to the case when at room-temperature. It helps to heat the case up when you go to put the liner back in, rather than forcing it.

   If it is already an easy slip fit at room temperature, it will just get looser as it heats up.

   Brett

BOILING CASE WITH THE PISTON AND CYLINDER LINER CROCK POT...

That's a huge NO-NO.

The boiling antifreeze will de-varnish the castor on the piston and the sleeve and you'll be rewarded with poor compression when reassembled.

Don't ask me how I know that.

YOU HAVE BEEN WARNED.

Heat the case w/piston and sleeve in the oven and use the Popsicle stick trick.

Andre

Thanks for all your advice...very helpful! I'll let you know how I get on.

Before I went all electric, I tried stuffing a Fox bypass once. I shaped a piece of maple to fit and used a little JB Weld to hold it in place. It ran great, a few times. Then it seemed like that engine wanted to overheat and run like poo.
That’s about the time I had my big sell-off of all things glow, so I never followed up on ~why~

I suspect the maple soaked up some fuel and swelled, impinging on the liner and putting a bind on the piston.

Whatever you use to stuffit, try to seal it up well.

 When I installed the popsicle stick in my Fox 35, my engine would start out in a four stroke , then run into a two stroke untill the last few laps. I’m thinking with the Popsicle sticks installed the engine is running hotter. I removed the stick and installed a larger spray bar and the engine does not runaway anymore.
Al

Al,
Your approach has worked for some. The stick in the bypass has been used for years to cure the "Fox Burp" particularly on profiles. You may have made it to wide which blocked off to much. Also, could just be that you loaded them motor more than what the conditions would let it cool properly, this is usually over prop. An open exhaust Fox35 can run a 10x6 prop when running at least 25% (50/50) oil. If you run a muffler you need to reduce the prop diameter about 1/2" (sometimes more, depending on the muffler type). In the earlier post you mentioned you were running GMA 10/22. With that low % oil it will do just what you say. Read Randy's post at the top of the forum about fuel for steel/iron plain bearing engines. The Fox uses oil to do two things, one is remove heat and second to increase the compression. I run the stock head, 7%N, 27% oil on a BYO 10x6 cut to 9 5/8" with a tube muffler, this works well in my 34oz El Diablo.
Best,    DennisT

Hi Dennis, I used a Bolly Clubman 10.5x5 prop with no muffler. I also tested with all caster fuel, 10-25 and 10-28  with the same runaway results once you start doing the pattern with the popsicle stick install. The popsicle stick I use was just the standard size that comes on most ice cream bars. I found that Powermaster GMA 10-22 has a very thick viscosity, similar 25% all caster. I found this out by running other brand fuel of similar oil content then switching to the Power Master, I had to open the needle valve 1/4 of a turn which was in the same range of the 25% all caster setting. I really became a believer of the GMA fuel when I used it running my Chinese made LA 25. I bought 6 of these garbage engines for speed limit combat. They would run for one minute then sag and shut off with 3 oz left in the bladder. I switched to 25% all caster fuel and the same thing happens but the engine ran longer and left 1 oz of fuel in the bladder, when I used  Powermaster GMA 10/22 the engine would run out all the fuel without sagging, and yes I went back to the other fuels which caused the engine sag and shut off. The piston and liners where the real problem with these engines and I replaced them with sets from Brian Gardner. The only good thing about the stock piston & liners was it provided a good testing platform for which fuel had the best lubricating qualities and ran the coolest. My Fox 35 runs real nice 424 with the Powermaster GMA 10-22, so there is no need for me to bring different fuel blends for different engines.
Al
Al

Al,
I wondering if the size of the stick could have impacted the engine run? The ones I have used are only about 1/8" wide. Seems you could over do it where you need to go to lean no matter what the oil %. Maybe someone with more engine history can comment.

Best,   DennisT

  The stick I use is 3/8 wide by 3/32 thick. If your stick is only 1/8 wide that would let more fuel in to cool the case better, but would have to glue in to the case so it does not move. The venturi on the Fox is .278 and comes with a .130 spray bar. In my opinion and testing that calculates to much area for a slow running engine of that size to run consistently though the pattern.
Al