Hi all,
I usually run gas air boats but I thought I'd try my hand at a nitro engine.

I bought a Tiger Thunder .61 pro W muffler. The problem I'm having with it is that the oil that is supposed to be coming out out the tailpipe is also coming out of the pressure nipple and clogging the tube so the tank doesn't stay pressurized.

Anyone think I'd be better off taking the nipple off, drilling the hole slightly smaller than the silicone tubing and inserting it that way?
The reason I ask is because a neighborhood kid has a nitro car (rc-10, gt, I think) and that's how his is set up.

Are you sure it's residual exh. oil clogging things? Maybe the press. nipple is restricted? You could try drilling it out...but I would first run a T pin through it to see if it's not plugged.

Might also be tank related?

i agree with proptop, i dont think that the HOT oil would plug up a line (will blow right through with no prob)
your problem is in the tank or the nipple

You can actually see the oil in the clear silicone tube. It plugs it so much that I have to run brake cleaner through it to clear it out. But it just plugs up after 3-5 minutes of running.

I't on an air boat so the tank is about 10 inches away from the engine.

it will always have oil in it, it is normal, there is oil in the fuel and there is oil in the exhaust and it will go right into the pressure line to the tank,air does not "blow" through the line, it just pressureizes the tank with a couple psi, when the tank is pressurized the flow stops but the tank is still pressurized.

Is the engine mounted in such a way that the mufflers press. nipple is at the lowest point in the muffler, and that is allowing more spent oil than usual to enter the vent/press. line?

I've never heard of this before?
Interesting...hmmm

edit: You could try drilling and tapping a new hole for the press. fitting in a different location on the muffler?

no. here is a pic.

One major problem I see is that the tank is WAAAYYY too low...that could be the reason it doesn't want to stay running.

It stays running in warm weather. It plugs a little, but not enough to kill the engine. When it's cold out....****utabouit!

and those fuel tubes bent at a 90 deg angle "may" be a prob(kink?)

little less than 90. I was very careful when I bent them.no kinks.

Wow! I wouldn't think the engine would draw fuel from a tank that low...not without a pump or regulator of some type.
Is there a check valve in the system anywhere?

I get that there is going to be oil in the line, What I don't get is why there is so much oil. 2-3 minutes and it's done.

OK, I am amazed that you can get it to run with the tank that low. I think if you will move the tank up behind the engine, your problems will go away. The pressure nipple should be toward top of the muffler in any case. If you want to leave the tank where it is, you might rig an oil sump to fit in the muffler line. Maybe out of a film cannister or small pill bottle.

Looked at your picture and read the posts over again. Your muffler tap is OK. Generally we don't run that long an exposed muffler line. If your problem is only in cold, that suggests that maybe insulating the muffler line when it is cold might help.

The amount of oil surprises me too...
Maybe we don't notice it in airplane installations because the vent/press. line is much shorter?

I had a check valve on the fuel side, close to the tank, but I think I had a faulty one. (It would allow the fuel to drain back to the tank.) It had fuel flow both ways.

Remember....I have no experience with nitro engines. I wonder if I tuned it right? I followed the instructions in the book and.....AH here's one for ya' After I run it.....if I tip it on it's transom.......oil will run out the tailpipe. I'd say 1-2 tablespoons worth.

Sounds like it could be running rather rich also? If you haven't leaned it out from the manual's recommended settings, then it could be really rich.

If it's really running rich, that would (at least partially ) explain the excess oil.

I have no idea. I Tuned it according to what the book said. Also, Comparing the neighborhood kid's car with tne boat.....I leave a trail of smoke whenever I nail the throttle....lots of smoke!

and why it dont like running cold.

How do you guys tune these things? I'm afraid to lean it out too far for fear of ruining the ehgine.

Get it running wide open and turn in (lean ) the high speed needle until it gets to max r.p.m. (peaks ) and then richen it back out a little...about 1/8 to 1/4 turn.

Then we can talk about adjusting the low speed needle...

this is a new engine right? and how much fuel have you ran through it? i guess im asking is have you completed breakin?