Newbie resurrection

[StevenMac]

Just made an introduction, and this is a follow-up that's more technical and fuel-specific.

I picked up a 1976 C&C 27 Mk III that's been sitting in its slip for two years. The PO pulled the carburetor off for maintenance, and in the process broke the copper line between the electric fuel pump and the carb. He never got back to it and two years went by. So far, with the help of this site and the Moyer manual, I've determined that the engine is build year 1976, with the late model 5-bolt carb. The carb has an adapter flange to accept the scavenge tube from the bottom, and that port on the manifold is plugged. Don't know why. There's another hose that would exit that flange and hold a little aluminum cylindrical thing that fits in a copper elbow coming from the engine. Don't know what that is.

The crank turns by hand, and a compression test was consistent across all cylinders. My thoughts right now are: siphon all gas out of tank, replace the main copper supply line with A1 rubber hose, replace fuel filters. Then re-install carburetor, again using rubber hose to replace the little copper one PO broke, but with an inline polishing filter. This is all to make sure that the first time I try starting the engine after such a long rest, I'm not introducing ancient fuel to the system.

I'd like to hear any suggestions, warnings, etc. I promise to run the blower for a long time before pressing start.

Thank you!

[StevenMac]

[lat 64]

Hi Steve,

That strange thing coming out of the block is an aftermarket crankcase ventilation valve. The original was just a rubber tube that came out and was sort of aimed at the intake flame arrestor on the carb. The intention was to suck up bad gasses and fumes from the crankcase and burn them in the engine. Some back and forth discussion about wether it's even a good Idea on these engines. I put one on mine but it's not a necessary piece to get started with.

I'd restore the scavenge tube; it's a safety feature.
Regarding running the blower: YES! And remember that a proper installation should not have any gasoline smells.
Tell everyone on board "If you smell something, say something"

Cheers and welcome,

Russ

[StevenMac]

Thanks Russ for identifying the ventilation valve. Any idea why someone would reroute the scavenge tube to a flange adapter and plug the opening in the manifold?

I'm struggling to post pics that aren't obscenely large. Will edit when I get that figured out.

[StevenMac]

Another thought that just occurred to me: perhaps I could disconnect the existing fuel line and hook up an auxiliary fuel tank, like for an outboard. The purpose would be to test out running the engine with new, clean gas before I start getting into all that business with the inboard fuel tank and lines. I figure you all must do something like this when you work on a motor on the bench, right?

[GregH]

Hi Steve,

That strange thing coming out of the block is an aftermarket crankcase ventilation valve. ...

Russ

That is from the indigo PCV kit; with that copper elbow.

[GregH]

Steve;

While you are adding new fuel hose and polishing filter between the pump and carb, think about also adding a fuel pressure gauge in this location too. It comes in hand when troubleshooting!

[StevenMac]

Thanks guys for the insight. Anyone have thoughts on the portable tank idea as a testing/temporary thing? If it works, I could potentially move the boat out of the PO's slip, which I need to do by the end of this month, or else have it towed.

[jcwright]

Hello Steve.

Here is a helpful thread on using a portable fuel tank. Note the safety precautions that are mentioned:

https://www.moyermarineforum.com/forums/showthread.php?t=5633

jack.

[sastanley]

JACK, that is a thread from the archives!

Steven, get a portable tank with a long enough hose you can keep it up on deck. There are legal implications to all that, such as squeezy bulbs and stuff, but most importantly is you being safe and not blowing yourself up with fumes in the bilge.

Don't worry about the aftermarket PCV fitting for now, but I WOULD solve the mini copper tubing (scavenger tube) issue coming out of the bottom of the carb and normally going back into the manifold via 1/8" NPT fittings.. For fuel feeds, you can use soft hose (i.e., have a barb off the portable tank, soft hose to a 1/8" NPT fitting that goes into the carb) for temp boat moving stuff.

We can work you thru this.

[StevenMac]

Thank you, this is precisely the kind of guidance I need. Any reason the "carb-to-carb" scavenge tube needs to be changed back to the original "carb-to-manifold" at least for now? Based on my intuition and what I've learned here, I will hook a fresh auxiliary tank up to the fuel/water separator and try to fire the old girl up.

[Dave Neptune]

The scavenge tube should be reconnected at the manifold. The "job" of the tube is to collect the raw fuel that precipitates out of the mix in the throat of the manifold at low velocity and drips back down to the carb throat, This fuel should be reintroduced at a point of higher velocity to carry it to the cylinders. That is why it is plumbed into a runner away from the vertical throat of the manifold so that fuel doesn't just fall back down to the throat. This tube is common on most updraft carb installations for SAFETY.

NOTE the tube is just 1/8 copper tubbing. Fittings and tubing are available in most hardware stores.

Dave Neptune

[Al Schober]

Personally, I don't see any difference in the scavenge tube going to that vacuum plate or into the manifold.
The safety item that no one has mentioned yet is the flame arrestor, required to be fitted on the carb inlet.

[ndutton]

The reason for the carb spacer plate is a vacuum source for the PCV valve. If you're not using the PCV valve, eliminate the spacer plate. You'll have at least 2 fewer possibilities for vacuum leaks.

If you are using the PCV valve be sure it's properly installed before trying to run the engine (see Greg's picture) or else you'll have a massive vacuum leak and she'll never start.

[StevenMac]

Hey hey, everyone. After following the advice I got from here, I gave the motor a shot today. After a couple tries, she fired up and ran! Smoked a bit at first, but that subsided. The oil pressure gauge only came up to 20, so I was a little concerned there. Coolant temp stayed around 180, which I understand is just right for fresh water system. The accessory belt is about done, so I'll look for a replacement tomorrow. But hey, she lives!