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Hooking up PCV hose to carb inlet

J

juryduty

Member
Hi again,
In swapping out a carb from one of my crusaders, the old carb appears to be a 1968 model (#7028282) even though the engines are 1975.

The new carb does not have a PCV port in the back like the old one did, but I found a plugged port in the front that looks similar, below the throttle blades.

Question is -- where can you find a hose fitting that goes into that port? It looks like something like a 1/2" brass hose barb might work, the existing hose looks like 3/8". I tried to unscrew the hose fitting from the old carb but couldn't do it without crushing the fitting. Any clues...

Here's an image of the port on the carb:
carbport.jpg
 
if you really want to be a purist......you can undo the three screws that hold the baseplate on, and swap them. it's really pretty easy and straight forward, no small parts will fall out.
 
You might want to check with the supplier of your carb before you go adding the PCV function....last thing you want to do is lean out the calibration they have provided...marine engines won't tolerate running lean for long...
 
All good ideas, thanks. I had not thought of swapping the base plate.

Are the brass inlets on a carb threaded -- i.e. is it possible to just unscrew the plug and screw in a hose barb? If so is it possible to buy these at any auto parts store?
 
This post scared me enough to call Edelbrock tech line and ask if, adding a PCV system to their 1409 marine carbs (I have two), would cause a lean condition, He said NO, since the PVC mainly works at idle. Under load the vacuum drops to nothing and practically they cease working.

Jeff
 
For the 1409 I think you have to drill and tap a hole for pcv? Sounds like you already did that. How do you like those carbs, I would like to get one but wasn't ready to take the plunge, plus the drilling thing...both of my crusaders take forever to start after a week cold and I think one of the problems is the bowl leaking out on one, not sure about the other.
 
I like the Edelbrock 1409s, though the engines run too lean with them. I had to re-jet one size richer on the main jets to get the plugs to stop coming out stark white.

Drilling the carb body for the PCV is no big deal--done several now--though I can understand the reluctance to take a drill to your brand new, 300 buck carbs! (Edelbrock claims the USCG regulations won't allow them to pre-drill and tap for the PCV line.)

On the empty fuel bowls after sitting a week, they also do that--it's a boating thing. I installed an electric fuel pump to refill them before starting the motors.

Jeff
 
The suggestion about checking with the supplier was directed at adding a PCV port on a q-jet that wasn't calibrated with a PCV system...A properly set up PCV loop will lean the idle mixture a bit but still be well within the idle mixture screw's ability to compensate. If the wrong parts are installed, the extra air can dilute the off idle mixture...
 
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