Mystery fitting

[old islander]

Can anyone tell me what this fitting is for? It's on the intake manifold of my 77 inline 4 120HP right behind the carb. It has a hollow black plastic tube coming from it that hooks up to nothinhttp://i885.photobucket.com/albums/ac52/oldislander/th_002_zps06a74http://i885.photobucket.com/albums/ac52/oldislander/th_002_zpse0454eee.jpg49f.jpgg.http://i885.photobucket.com/albums/...ms/ac52/oldislander/002_zps06a7449f.jpg[/IMG]h_002_zps06a7449f.jpg[/url]

 

[stratcat88]

Re: Mystery fitting

Can anyone tell me what this fitting is for? It's on the intake manifold of my 77 inline 4 120HP right behind the carb. It has a hollow black plastic tube coming from it that hooks up to nothinhttp://i885.photobucket.com/albums/ac52/oldislander/th_002_zps06a74http://i885.photobucket.com/albums/ac52/oldislander/th_002_zpse0454eee.jpg49f.jpgg.http://i885.photobucket.com/albums/ac52/oldislander/th_002_zps06a7449f.jpg

dont know, but thats a nice boat. you put a hard top on it with some eisighn glass and it would be sweet.

 

[84EdH]

Re: Mystery fitting

O.I : I tried to view the pic you linked........got nothing.

 

[ktbarrentine]

Re: Mystery fitting

Looks to be on the intake manifold cover.... Parts site lookup seems to show a plug there. See here:

http://www.mercruiserparts.com/Show...sc=INTAKE+MANIFOLD+COVER+AND+THERMOSTAT+COVER


I would say by that then it used to be hooked up to a vacuum gauge.

 

[old islander]

Re: Mystery fitting


Ok, now it worked

 

[old islander]

Re: Mystery fitting

I was thinking manifold vac gauge also, but the boat never had one. Should I just plug it and forget it?

 

[ktbarrentine]

Re: Mystery fitting

I would plug it as shown in the diagram... Unused, it is a potential vacuum leak. (Maybe a previous owner had it on there for diagnostic purposes?)

 

[old islander]

Re: Mystery fitting

Thank you kt. Off to the hardware store....

 

[Grub54891]

Re: Mystery fitting

Remove the fitting,put a brass pipe plug in it. It'll look factory fresh instead of rednecked.

 

[Bob_VT]

Re: Mystery fitting

That is the bleeder line that goes to the fuel pump. In the event of a fuel pump failure it will bleed the fuel directly into the manifold. If your fuel pump does not have a small line to the manifold then it is possible that you have the wrong fuel pump.

 

[thumpar]

Re: Mystery fitting

Usually the tell tale from the pump goes from the fuel pump to the carb and is clear so you can see if there is fuel in it.

 

[Bondo]

Re: Mystery fitting

I would plug it as shown in the diagram... Unused, it is a potential vacuum leak. (Maybe a previous owner had it on there for diagnostic purposes?)

Ayuh,.... That's My thought,.... Put a brass pipe plug in it,....

Manual fuel pump vents don't go to full manifold vacuum,....
Usually just to the flame arrester/ carb throat,...

 

[ktbarrentine]

Re: Mystery fitting

Usually the tell tale from the pump goes from the fuel pump to the carb and is clear so you can see if there is fuel in it.

+1 on that.... It would never (I've never seen it) inject straight into the intake manifold. The fuel sight-flow-tube is clearish-yellow and goes from the fuel pump to the airhorn of the carb (part number 32-7381567). Got one of those lines?

 

[old islander]

Re: Mystery fitting

yes, the line from the fuel pump goes to the carb body and is much larger. That's not what this is. The only thing I can think of is someone used this at one time for a remote vacuum gauge to tune the carb mixture. Anyway, I guess it's still a mystery. I just plugged it with a brass pipe plug and moved on to rebuilding the trim motor. Thanks for the help guys, Happy boating.