Don, /#3 Bleed line has hole burnt through it ??????????

[Nikon Man]

While at the ramp today trying to put some hours on the new motor, kept hearing this noise.......sounded like a High Pressure "PSSSST"/or like a high pressure pop off everytime #3 fired. Pulled the cowl and fired it up again and saw puffs of smoke everytime I heard that "PSSSST" sound. Shut it down and looked around and found #3 bleed line burnt with a hole in it in the middle of the bend about 1 1/2" off the nipple in the block. It's definetly a burn through the line. I'm open for ideas because I'm somewhat clueless, it's not from contact with anything else and there's no sign of wear on the OD of the tube.

[EuropeanAM]

Verify the check valves for that particular bleed line.

[Nikon Man]

Don,
This motor has the manifold type check valve & checks good. I'm thinking that it's maybe the el-cheap-o bleed lines themselves (not OEM). Does Merc use a special type hose that was some resistance to a back flame ?


Modified by Nikon Man at 5:52 AM 6/8/2010

[EuropeanAM]

There are several different types of bleed lines available. If you can determine the "size" you have, I'll see if I don't have some "more durable" material here.

Any compression or timing increases on that engine?

[Nikon Man]

Don,
Thanks for the reply. I spoke to a couple of racer buddies and they provided me with some 1/8" ID x 1/4" OD Tygon "Yellow" Fuel Grade Tubing. I'm gonna give that a shot.

[EuropeanAM]

Great! If that doesn't work for you, let me know. I probably have some "double-wall" tubing here....

[Nikon Man]

Thanks Don, just as an FYI, I stopped at my auto parts store and pick up 10' of heavy walled vacuum line 1/8 ID x .360 OD and replaced all my bleed lines just as a test. Problem did not resurface, so I'm thinking it was my thin wall El-Cheap-o lines........