Is this a marine fuel pump? (Pics attached)

cheburashka

Senior Chief Petty Officer
Joined
May 28, 2005
Messages
715
'74 Mercruiser 140.

Brief update--I decided to replace my fuel pump without the clear overflow line with one that had a fitting for the overflow line, just for the sake of safety. Now, I've got a number of problems specifically related to the fuel pumps. They are:

1) Is it possible that the old fuel pump (on the right in the pictures) was also a marine pump, and that the fitting for the clear line to the carb had been plugged by whoever installed it, instead of correctly running a line to the carb? There is an aluminum plate sandwiched between the two diaphragms, and it appears to have a place where a fitting for the hose would go. Is this the proper fuel pump for this engine?

2) Is the pump on the right rebuildable? If so, what comes in the rebuild kit?

3) I filled up with gas today and ran at idle for fifteen minutes or so, and ran at full throttle for three minutes. When I disconnected the fuel pump, I got a steady flow of gas out of the hose that connects to the inlet even though I was holding it above the level of the tank. Could this have been caused by leftover fuel in the filler pipe? I know my vent is working, so I'm sure it isn't pressure, but I can't believe that fifteen minutes of idling and three minutes at full throttle wouldn't have drained the filler hose.

4) Is anyone familiar with the Carter pump on the left? Is it appropriate for the engine I installed it on? I've had nothing but problems since I installed it.

Thanks for your help.
 

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cheburashka

Senior Chief Petty Officer
Joined
May 28, 2005
Messages
715
Re: Is this a marine fuel pump? (Pics attached)

I think I found a picture of the fuel pump that was on the engine when I bought it. It looks like an 18-7275, which came on the 7.4 liter engines.

The description of this fuel pump says that it has no provision for carb vent line. If that's right, then what is the purpose of the fitting in the middle of the fuel pump with the allen-head plug in it?

Also, I'd like to know the difference between a fuel pump for a big V8 and one for a 4-cylinder. Is it just a difference in the size of the diaphragm? Why would someone have put a V8 pump on a 3.0? Is it dangerous to run it like this?

Thanks
 
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