View Full Version : 1989 Merc 70 mystery barb on block

03-24-2019, 04:08 PM
19835There’s a small hose barb on the block just below the 3 carbs.
When running it seems like air/fuel is coming out. Where should the hose be going? There is no hose currently and any obvious parts. Should it just be capped?

03-24-2019, 04:42 PM
Most motors use an oil recirculating system-----Takes oil from bottom of the block to the top.-----Consult a manual or your trusted local shop.----Do not cap it off !!

03-24-2019, 05:42 PM
I forgot to say that the oil injection system has been removed and I mix the gas/oil the old fashioned way.

From a parts brake down online it looks to be a check valve for carbs.
So maybe cap?

03-25-2019, 08:55 PM
So it’s for lower bearing oil. But can’t find where to connect to. Delicious manual is useless

03-25-2019, 10:33 PM
????-----Oil injection or no oil injection.----You need that recirculation hose installed.-----Do not cap it.-----Confused ?---Then hurry to a boat shop.