Stray rubber tube on 850 engine

D

Dave Bassett

True Classic
Having recently had a right shoulder surgery that makes it difficult to do manual tasks, I recently took my car to a local shop that has treated me well for decades. It came back running very well with a number of issues seemingly sorted out.

Yesterday I was poking around the engine bay with my one available hand and found a loose hose that appears to be a vacuum line. Initially, my thought was that the vacuum advance line had come loose and I would simply reattach it to the vacuum advance diaphragm. Then I looked at the distributor and realized there seems to be no vaccum advance assembly. I double-checked a spare distributor and it too seems to have no vacuum advance provision. When the car is running, the hose itself has no appreciable vacuum or internal pressure. The car runs the best ever since it has been under my care.

I traced the hose back to the vicinity of the carburator, all I could do as I really can't do mechanical work right now, and it appears to go up to the underside of the carburator near the firewall.

So I am perplexed. The hose is probably eighteen inches long and is running from the vicinity of the carburator, mixed in among the spark pug wires, toward the "front" of the engine and might barely reacch the distributor.
Any thoughts and guidance are appreciated. I can take it back to the shop and they will do the right thing but want to understand this. Thanks.
 
Guidance:
1. Always post photos so we can see what you are talking about.
2. since we don't know if your air filter, pcv system or anything else has been altered, pretty much imposible to guess what his random hose is.
3. Again, no photos.... I got nothing.
 
Thanks for your response. It is a 1972 and the emissions equipment has been removed. It previously had a charcoal cannister and a pre-heat mechanism that ran from one of the headers to the air cleaner. It now has a non-stock oil bath air cleaner. The PCV tube was retained but the other, smaller hose running to the air cleaner was not and I was told that its source had been capped. Perhaps this is that hose. I will reitterate that the culprit hose has no discernible vacuum or pressure function so perhapsit it simply a vent.

It is not really feasible to get photos as the culprit hose has its source right next to the upper radiator hose and the radiator fan shroud. There is no way to get a cell phone into position without removing things. I felt around a bit more and the culprit hose goes up vertically past the carburator drip tray to attach, still vertical, to a connector tube (nipple or whatever) that drops vertically from the carburator.
 
The drip tray has a pipe brazed to a nipple. Gas that may spill out of the carb drains down the pipe to a rubber hose that keeps the gas away from the starter. If your trip tray is missing the pipe, then its likely the mystery hose should be attached to the pipe. See the photo. You could add a piece of brake line by brazing or a big glop of epoxy.
20200718_093816.jpg
 
Dave Bassett said:
Thanks for your response. It is a 1972 and the emissions equipment has been removed. It previously had a charcoal cannister and a pre-heat mechanism that ran from one of the headers to the air cleaner. It now has a non-stock oil bath air cleaner. The PCV tube was retained but the other, smaller hose running to the air cleaner was not and I was told that its source had been capped. Perhaps this is that hose. I will reitterate that the culprit hose has no discernible vacuum or pressure function so perhapsit it simply a vent.

It is not really feasible to get photos as the culprit hose has its source right next to the upper radiator hose and the radiator fan shroud. There is no way to get a cell phone into position without removing things. I felt around a bit more and the culprit hose goes up vertically past the carburator drip tray to attach, still vertical, to a connector tube (nipple or whatever) that drops vertically from the carburator.
Click to expand...
Could it be the purge line from the (now missing) charcoal canister to the carb?
 
Yes, if it is going up past/above the drip tray, then it is probably emissions/fugitive vapour and probably goes into the bottom of your air cleaner housing
1704594294398.png
Probably should be capped but is unlikely to be having any impact.
 
dnudelman said:
The drip tray has a pipe brazed to a nipple. Gas that may spill out of the carb drains down the pipe to a rubber hose that keeps the gas away from the starter. If your trip tray is missing the pipe, then its likely the mystery hose should be attached to the pipe. See the photo. You could add a piece of brake line by brazing or a big glop of epoxy.View attachment 80328
Click to expand...
A red "drip tray"?
 
Thanks folks. It seem likke we have two likely suspects.
1. If it attaches to the carb it is a vent that can be ignored, capped, or run to the air cleaner.
2. If it attached to the (not red) drip tray it is a drain that needs to be routed tobelow the starter.
 
So, I found the drip tray drain and the tube is attached and routed over the bell housing and down the other side. That leaves the fugitive vapor recovery mechanism, which the shop owner said he capped. The lenfth of the house suggests it was routed to the other side of the carburator to the air cleaner housing and may just not been removed. I appreciate the helpand willinvestigate further.
 
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