Logo
FULL SITE MENU

Bizarre sudden appearance of oil/soot in cooling water after oil change

I’ll take a look in my OMC factory shop manual I know they used the same 3.0 with the same 2bbl Rochester as Merc. 2GV I think it was. Anyway you want to make sure the choke closes or mostly closes with a cold engine and the choke pull off pulls the choke open a fraction of an inch as the engine starts.
 
BTW that black hose that goes from the fuel pump to the carb is supposed to be a yellow tygon hose so you can see if the fuel pump diaphragm leaks. You’ll see liquid in that hose then; time to replace the pump…
 
louc said:
BTW that black hose that goes from the fuel pump to the carb is supposed to be a yellow tygon hose so you can see if the fuel pump diaphragm leaks. You’ll see liquid in that hose then; time to replace the pump…
Click to expand...
Thanks, louc and kghost and others...I ordered that hose. But if that tygon hose is a fuel line from the pump to the carb, shouldn't I see liquid in there if the pump is working correctly? I must be missing something about the flow of fuel from pump to carb. kghost said "The sight tube will show gas if the mechanical fuel pump diaphram ruptures which will fill the line with fuel and dump it into carb.
 
The main product of the pump is delivered thru the 3/8" metal line, in the factory configuration...

The sight tube will fill when the diaphragm internal to the fuel pump starts to leak...the tygon carries the fuel from the pump to the carb where it is dumped into one of the primaries...the earlier designed let the fuel flow into the crankcase....and was a major accident waiting to happen...
 
Mike,

For clarity,

Automotive mechanical fuel pumps, if the internal diaphram leaks, there is a weep hole that allows the gas to drip down onto road service.

For all marine mechanical fuel pumps, there is a barbed fitting in that weep hole and the yellow hose attaches to that barbed fitting and also attaches to a barbed fitting in carb.
As Mark said, if Diaphram ruptures, gas will leak into yellow hose and flow to carb.
This will cause a excessive rich running condition. (Which you were reporting)
This is why its important to be able to see if gas is flowing. The black hose did not allow to see if gas was flowing.
If pump work correctly and no diaphram rupture, NO gas will be present in yellow line.
 
kghost said:
Mike,

For clarity,

Automotive mechanical fuel pumps, if the internal diaphram leaks, there is a weep hole that allows the gas to drip down onto road service.

For all marine mechanical fuel pumps, there is a barbed fitting in that weep hole and the yellow hose attaches to that barbed fitting and also attaches to a barbed fitting in carb.
As Mark said, if Diaphram ruptures, gas will leak into yellow hose and flow to carb.
This will cause a excessive rich running condition. (Which you were reporting)
This is why its important to be able to see if gas is flowing. The black hose did not allow to see if gas was flowing.
If pump work correctly and no diaphram rupture, NO gas will be present in yellow line.
Click to expand...
Ahh, I see, thanks for that. Excellent explanation. Indeed as jimn said, though it has 74% good reviews, some of the reviews for that tubing you recommended are not very good. I'll shop around a bit before using that one.
 
kghost said:

Mercury Quicksilver 32-73815 67 - Tubing - 42 Inch

Visit MarineEngine.com for Mercury Quicksilver 32-73815 67 - Tubing - 42 Inch 257 price, stock and delivery options to order online.
www.marineengine.com www.marineengine.com

here is the OEM Listing here.
Click to expand...
I wouldn't mind knowing why this is sold in lengths that are so much more than a single engine needs. I understand that it costs money to cut it to any length, but this is double the length needed.
 
They order in bulk. They select the longest needed and add a few inches then order. Sell the same part and part number for all carbed models.

Simple.
 
kghost said:
They order in bulk. They select the longest needed and add a few inches then order. Sell the same part and part number for all carbed models.

Simple.
Click to expand...
Sure, THEY order in bulk, but boat owners don't need more than enough to reach from pump to carb. The piece in my boat lasted more than 35 years.

I guess I could plan on keeping the boat and planning for the future.....:)
 
kghost said:
They order in bulk. They select the longest needed and add a few inches then order. Sell the same part and part number for all carbed models.

Simple.
Click to expand...
For some reason, your user name looks familiar- do you use it on other forums?
 
Back
Top