I've installed my thunder tiger pro .36 engine but the instructions do not mention what these o rings are for? ( see pic )
Are they spares for something in the carb?
this is my first venture into glow engines..

Also I'm not sure how to route my fuel lines. they exit the firewall right behind and below the engine.
I would think care must be taken to avoid touching the hot engine? will it melt the line? how long is to long for the hoses?
I just finished adjusting the front wheel and will add the side cowling on this side of the engine.

I'm hoping to fire the engine up today!!!

Thanks

Pop

here are the pics!

Pop

Doesn't look like the picture worked,

fuel lines should be kept as short as possible

Doesn't matter if the lines touch the engines they don't get hot enough to do anything


Steven

Edit : I see the pics are now up, the fuel lines look WAY to long, also to me those o-rings look like extra o ring for the high speed needle calve

Thanks Flying Freak,
I'm waiting till the last minute to cut the lines down. I've learned to many times its tough to make them longer.
I'm thinking of taking the engine off and bringing the hoses out above the engine. Its a long way around from the bottom as they are set up now.


Pop

I've got filters in these two lines so that I can more easily fill and empty the tank. I disconnect the green hose from the filter and connect it to the fuel pump line. The muffler pressure line goes to the overflow in the tank. With clear tubing and brightly colored fuel, it can remain connected and still show when the tank is full. But I've provided a connection since I often use almost clear fuel.

You want the lengths to be just long enough.

Hey DaRock, what is this thing that is extended out of the wood? That thing that i thing come from the carb. It looks like a piece of linkage i think. It's on the right of the photo you post.

Looks like the engine is coming off!
Thanks for the pic. I was thinking of putting filters in on the plane. LHS sain a filter in the line when I load film is enough.
Do you have one going to the muffler? I dont see any clamps? are they not needed?

tia

Pop

Possibly like this one?

The O rings are just spares for the needle valve some have two and some just one, make sure you needle has o ring(s) on it already.

That's the needle valve extension. It's a braded wire with a collar at the end. The braided wire can be cut to almost any length. It does not transmit as much vibration as a solid wire would transmit. And the collar can be placed to match the length.

The needle valve body has a gib screw setup in it. You can place a solid wire extension or the supplied braided wire one. Nice feature.

BTW, guys used to make their own braided wire extensions all the time in years past. Any braided cable works and small collars are easy to find.

Yes, there are two filters in the pictures.

Clamps are not needed. Buy tubing that fits and clamps are a waste of time. The excellent quality silicone tubing that's available everywhere absolutely does not need clamping. It's so easy to find tubing that fits the filters that're available, and filters that fit the tubing that's available, that it's really funny to experienced modelers to hear that clamps are needed and that more connections are more risk. OK, it's not funny anymore, it's actually sad. Truth is, if a modeler hasn't been able to work out sticking a hose on a fitting, he probably ought to find another hobby. (OK KIDDIES !! IT'S FLAME TIME.....)

There is a filter on the muffler pressure line. It's there mostly to provide a secure and available disconnect point. I would not have bothered except this line is "above". When I use simple two line plumbing, the line that provides muffler pressure goes to the overflow pipe in the tank. When the layout of the pressure tap in the muffler and the location of the muffler is "below" and the overflow easily drips out the muffler pipe, you don't need to do anything special to the line. Also, if the line is very transparent and your fuel is dark enough, you don't need to squirt the overflow to know when the tank has reached overflow. Well..... I also wanted to see how much crap a muffler blows down the pressure line. And I wanted to see if a filter in that line would affect the engine. And the line wasn't easy to see the fuel flow. So..... I stuck that filter in that line.

And yes, there is a filter in the delivery line.

The LHS said something they believe in. There is much more to the story than that. Experience will show you what you wish to do with filters. It should also teach you how to stick a tube on a fitting. And teach you what tubing fits what fittings.

That airplane has flown around 5 to 25 flights a week since last year with the plumbing you see in the picture. It's worked perfectly from day one and is still working perfectly. I've cleaned the pressure line filter every time I've had it open. I've yet to have to clean the delivery line filter. Not once has any connection come loose. Connections that are not disconnected regularly tend to seal themselves. Working connections will tell you when the tubing is relaxing. I've yet to see any of the modern tubing do that in the last 20 years.

Use quality tubing that fits and the extremely slight risk will not warrant using clamps. If you think clamps are needed, use 'em. But don't use the ones that might cut through the tubing and cause problems.

BTW, I test things I wonder about. And I wondered about how much junk a muffler blows down the muffler pressure line. So I stuck that filter in that line. I wanted a disconnect point and was cutting the line anyway, so I decided to do the test while I was at it.

If you look closely, you'll see that the filter on that pressure line is backwards. Yeah, some filters work better one direction and not so good in the other. The screen is usually at one end of the filter body. Sometimes the inside of the body is larger than the flow-through diameter of the fittings on the end. The idea is to provide room for the junk that's being trapped.

BTW, years ago, modelers discovered that the larger cavity a filter provides can cure engine run problems. But that's another story.

Anyway, when I first placed the filter ane when replacing after checks, I paid great attention to insure that the cavity was toward the muffler. After later inspections turned up less and less junk, I quit paying attention to the filter orientation. So the experienced modelers with sharp eyes and good observation skills will notice that I've committed a grievous sin, and put the freekin' filter in the line "backwards". Guess I need to either go take another picture or doctor that one.

Everythings back together and looks good to me?


pop