Small tube from intakes question

[Jake222]

Hello. I have a 1978 mercury 800 80 hp. I was redoing the internal fuel lines yesterday and accidentally broke this small tube which is connected to an L connector that connects both the intakes. (2carb). I’m not sure what this small tube does I’m guessing it allows for a small extra amount of intake for air when idling because it runs through the cowl to the outside. I can’t find any part number for the life of me to this L connector and don’t see it completely essential to the functionality of the intake or engine if it’s still getting air just not through the little hose that leads to the outside air. If someone could enlighten me with a part number or knowledge it would be great assistance.

 

[racerone]

I am not there to closely inspect this.-----Appears to me that it is part of the oil bleed / recirc system

 

[QBhoy]

If I didn’t know better about this old engine not ever having oil injection...I’d say they were oil injection lines. But I’m pretty confident these didn’t have that. Is there a chance more modern carbs were fitted to it...if they are even compatible? All I can think of.

 

[racerone]

??------No oil injection on a 78 model !-----There is an oil recirculation system on most outboard motors.-----On some motors they are external and visible.---On some they are internal passage ways.

 

[Jake222]

I just want to find the part number so I can reconnect the hose . Here’s the site for parts list. https://www.perfprotech.com/mercury...00 (4 CYL.), 80 (4 CYL.)/4831999-thru-5582561

 

[Jake222]

i did blow through the small tube and it was as if (I think)the line was just leading to an opening in the cowling to the outside air. I’ll double Check but definitely no resistance when blowing air through it. The only problem when I was searching for the spot on the outside of the cowling is that where the tube leads to is in a really weird spot that I couldn’t inspect easily from the outside of the bottom cowling. I’m trying to explain the best I can.

 

[racerone]

Is the bleed / recirculation hose from the bottom bearing to the upper bearing in place ?-------Do I see an electrical cable that is cracked with " green copper " showing.-----I see no reason for that wee hose to feed air to this engine.------Research this carefully or visit a MERCURY shop with a grey haired mechanic.-----Or post your question on ------johnsoldmercury----website.------If the motor was in front of me with some incentive I might be able to figure it out !

 

[Jake222]

https://www.perfprotech.com/mercury...-crankcase-assembly/assembly/484/10?model=854

if I’m not mistaken it’s either #20 or #25 on this page. Bleed tube connector.

 

[Jake222]

Considering it’s only one single hose I’m leaning towards it being #20.

 

[Jake222]

Not correct!

 

[racerone]

There is a bleed hose and a balance tube.-----Order both if you like one might fit.

 

[Chris1956]

Those inline motors had two tubes running on the starboard side of the block, next to the carbs. The smaller tube was to send excess oil from the lower main bearing to the upper main bearing. The lower brass pipe fitting was a 1 way, and the top brass fitting was open. That looks to be the item you are asking about.

Most auto parts store should have that size rubber hose. Clean the lower fitting and make sure the upper fitting is clear,

The other hose was about 1/4" in ID. It was a balance hose connecting the crankcases of all cylinders together. Hose material should be avail at most auto parts stores, as well.

 

[The Force power]

I can't recall #17 being a check-valve or just a fitting, #20 bottom one for sure. before you put the hoses on; check if both are not plugged. this is important because the excess oil/fuel that flow through is also to lubricate the top bearing

 

[Faztbullet]

Its actually #23 but is it NLA....just solder it back in place.

 

[Jake222]

I wold have to agree and say it probably serves the same purpose as #23 but mine instead of having the t connector in between two tubes it has just one tube. and the bottom connector is like a T connector but has the smaller bleed hose connector on the side not making it a classic T connector

 

[Jake222]

like this but the side hose is smaller than the balance hose

 

[Jake222]

https://www.ebay.com/itm/53491-TEE-B...-/400489957347

this is pretty close even though that would make the bleed hose go out downwards, not the side, I think its my only option.I found a brand new one and ordered

 

[QBhoy]

??------No oil injection on a 78 model !-----There is an oil recirculation system on most outboard motors.-----On some motors they are external and visible.---On some they are internal passage ways.

So a 78’ merc like this has oil injection ? Is that what you are saying ? Totally didn’t know that. Are you sure ?

 

[QBhoy]

??------No oil injection on a 78 model !-----There is an oil recirculation system on most outboard motors.-----On some motors they are external and visible.---On some they are internal passage ways.

Just read again. I think you were probably just agreeing with me that it doesn’t have oil injection. Got you now.