manks7477

I have a lovely OS 91 FS sitting in the front of my 4* 60. The plane and engine have been stored for a couple of years nose down in my basement.

I am trying to get back into the air in the next little while and getting my planes ready to go. I turned the prop on the FS and there was no compression. I have taken the valve cover off and sprayed it with brake cleaner, I will oil shortly as well.

I can see that the valves are not moving at all with I turn the prop. They seem very stuck.

What do I need to do next? How big a problem could this be?

Thanks in advance for your help

MetallicaJunkie

First soak it or just squirt some glow fuel or oil just to get it lubed up and fire it up , the ring will "open" up...From my experience most ringed glow motors lose compression when they are stored away for a long time or gummed up from lack of use

manks7477

soaked overnight in glow fuel. Does not seem to have changed much. I can hear some air going through the engine, but no real compression, valves not moving

Gizmo-RCU

My Feedback: (27)

Often you can soak the valve stem with glow fuel then turn over the engine with your finger on top of the rocker forcing it to follow the cam in a normal action, use a heat gun to warm it up prior to this so the fuel will follow down the valve stem before to this is tried.
You can gently rock the valve many times and loosen congealed oil enough to acomplish freeing the valves. After the valves are working properly run the engine a little rich and for a tank or so, should take care of your problem. (Be careful to watch for the push rods
coming off the rocker during the valve loosening activity , if it happens just push the valve down and place the rod into the socket).

manks7477

Thanks for your help. I have it soaking in Antifreeze right now in a crockpot on medium heat - maybe 130 F - hope that will help. It has been a couple of hours now.

This fix is getting expensive!

JollyPopper

My Feedback: (6)

A friend brought me an Enya 80 four stroke a week or so ago that had no compression and I found the valve stems stuck in the tubes. I soaked it in antifreeze in a crockpot overnight, but it was probably 150-180 degrees. The valve stems freed up and the engine ran OK afterwards, but it will take a tank or two for it to be right. The point is that the hot antifreeze did its job.

manks7477

Exactly what I did, bought a used crock pot at a second hand store, anti-freeze and when at 'er. Took the carb off the engine and the glow plug out and in it went. After a couple of hours I took it out, it almost seemed like it seized up, but I put some oil on the valves, and a few other places and it was spinning like it did the day I took it out of the box. I will run a take or two on my test bench, the put it back in the plane ready for spring! I did the same thing with an old OS 46 FX and it too looks and feels like new. Lots of compression, clean, I have three more engines taking a bath overnight!

bigtim

My Feedback: (13)

just make sure that crock pot is now labeled "not for human consumption" the anti freeze makes it toxic

manks7477

Big Tim - Have already done that.

OK, so this now becomes the end of the story.

The engine has been mounted on my test bench, There is lots of compression and it looks like it just camout out of the box. Fueled it up this morning, put a new Glow Plug in and tried to light it up.

First time I tried the engine jumped to life! I ran a tank of fuel and shut it down.

I tuned it and let it run, not a sputter. Perfect run for over 10 min. My baby is BACK!

Now I will put a drop of oil in and remount it in the plane, waiting for the spring to come and the snow to melt!

Thanks for all of the help!