Trogdor the Burninator

I'm just about to get back into glo power but before I blow any dough I thought I'd reacquaint myself with typical glo engine operation by getting my old Thunder Tiger .15 engine on my old Thunder Tiger Trainer 15 model! Ok, I bought these in the mid 80s and haven't really touched them since the 80s!

So, I completely took apart the engine and other than a totalled gasket on the back plate it looked pretty good, although a little crusty and oily... so I then soaked everything in engine cleaner and scrubbed it with a toothbrush and it all came out looking pretty good.

Now my question. I bought some blue RTV gasket stuff at the auto parts store since I saw it somewhere to replace the dead gasket... I'm supposed to put a thin layer all around the backplate, let it dry a little and then assemble, right? Then the only other seal is around the carb... one of the 2 screws holding it on is a little stripped (plastic carb) but I do have the rubber o-ring seal... should I use some more of the rtv stuff around the carb o-ring and the screw holes as well? Any other seals I'm forgetting? Only other thing I remember is a thin metal washer on the front of the crank between the engine and the prop hub thing... oh ya, there was no muffler gasket... should I use more rtv on that seal?

Thanks for any insights...

downunder

The RTV should be fine as a seal but I'd let it dry completely first or you'll glue the backplate on
But seeing you've got that steel shim thrust washer means you're engine uses a bushed crankshaft (and don't forget that shim if you use an electric starter!) so there's something to check before you assemble the engine. With the RTV the backplate will fit further inside the crankcase by roughly the thickness of the gasket. Fit the crankshaft along with that shim and mount a prop on it. Put on the backplate with no sealant and nip it up. Now push hard back on the prop as though you're using your starter and turn the prop and see if the crankpin touches the backplate. Chances are it'll be fine because there's usually a reasonable clearance. If it touches, you need a gasket.

ZAGNUT

My Feedback: (1)

i had one of these early TTs back in the mid '80s too. it was loop scavenged with a lapped iron, baffled piston. if your's is the same be sure to use lots of castor. modern synthetic based fuel with a couple ounces of castor added will not work here.

it also didn't work too good without an idle bar plug but i can't remember if it used a short plug or standard length.


dave

gcb

For the backplate you can also use an old playing card or manila file folder to make a new gasket.

I would use a short plug. Some brands use a size that is somewhere between short and long so it can be used by both. If you use a long, check that the idle bar does not hit the baffle on the piston. Otherwise the long should work also.

If the engine was run extensively prior to cleaning you may have removed some varnish that helps increase compression. If this is the case, use all castor lube and the compression will return after some running. If it is relatively new, some synthetic will keep off the varnish until you need it.

Good luck with it. Keep us posted on your results.

George