Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

[madurodave]

This year my buddy and I are hearing a new sound from the top of his 1988 OMC Corba Sterndrive engine. We have pinpointed it to this small hole (please see the picture below). We are not sure if something fell out of here or is missing because when we cover the hole with a finger, the tapping sounds (vacuum leaft sound) stops.

This is just to the left of the carburetor.

I would just cover the hole but it is here for a reason. Can anyone shed any light on what this is for or how to fix? I scoured the manual last night, to no avail.

Thanks in advance.

 

[HT32BSX115]

Re: Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

Howdy,


It might be helpful if you indicate what engine you're talking about.

I assumed that it is a 5.7L engine. That thing appears to be the "Choke Tube" , OMC 0914352 It is a small tube that is placed in the exhaust cross-over that allows a little bit of exhaust gasses to be routed to the automatic choke (bi-metallic strip) to open the choke.

You can view the item by going to http://epc.brp.com (You do not have to enter your email address)

go to Stern Drive in the drop down menu and find your year and model number.

It may have rusted off internally and is just an exhaust leak now.

You should fix this. it's an exhaust leak there that could be a source of ignition if you leaked a little fuel onto the top of the engine

I am not sure you can buy it.......You might be able to make one though..... You might have to completely seal it off with a block-off plate and install an electric choke. You may also be able to run without a choke altogether if you only operate in warm weather. (I disconnected mine several years ago.)

ymmv....


Rick

 

[Joshua Nichols]

Re: Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

Choke stove I believe is it's name.. That hole is suppose to be there.. You might wanta pull it out to be sure the tube is still in there... They are notorious to breaking off.. BTW it is a PITA to get out of there..

 

[madurodave]

Re: Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

thanks guys. very helpful

 

[madurodave]

Re: Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

Dont need the choke. Can i put some jb weld on it to seal or any other suggestions?

 

[Joshua Nichols]

Re: Vacuum leak maybe? Please help with 1988 OMC Cobra sterndrive

This is what I would do.. Leave the plate there.. Don't want the choke? Adjust it where it will stay open all the time.. That hole.. There is no vacuum or anything there.. Why stick JB weld all over the place? If it is leaking exhaust that's a different matter.. Plug up the two holes

Do ya still think you have a vacuum leak somewhere? Sometimes you can find a leak with carb cleaner.. It will raise the engine a bit when you spray the spot of the leak.. Old trick is squirt a dab of engine oil in the place you suspect a leak.. The vacuum will suck in the oil and seal the leak for a second giving you a chance to find it..