Fuel pump

S

Steve OD

Member
Oct 26, 2017
70
West Yarmouth, MA
Boat Info
Sol Searchin'
1996 330 Sundancer
Engines
7.4 L V Drives
I just tuned up my engines and had the carbs rebuilt. Last fall the starboard engine was not running properly as the carb was corroded, but it would start, just not run well and cut out often.
When I tried to start it up, no fuel was coming into the carb, if I primed it, it started right up.
I took the fuel pump out and it was frozen. So I have a new one on order.
My question is: there was fuel in the area where the shaft and cam are, I assume the pump was leaking. What should be in there? It seems like there should be some type of lubricant.
Also, when I reach in, I can spin the metal collar around the shaft that I believe should have a cam to press on the lever for the pump. Should that spin freely?
Thanks!
 
Working from a a couple of assumptions from my 1990 7.4's: You have mechanical fuel pumps? Also, when you say there was fuel where the shaft and cam were, you are talking about the fuel pump shaft and cam - not the carb area. See the picture I have attached. If this is a mechanical pump, there is a pump shaft that goes up into the engine block that moves up/down (at an angle to the block) that is driven by the camshaft. The spring pressure of the pump returns the push rod to the up position on the upstroke of the lobe. There should not be ANY fuel inside the block at this location. The push rod should be installed with cam lube on the ends and the engine oiling system takes care of it from there.
 

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yes it does, I did find an old post about changing the oil in the reservoir every year, you have to siphon it out.
Im more concerned about the shaft itself, and the fact I can spin it with my finger, how does it depress the plunger if there is no cam on it?

Scofflaw, I have my own dock in Mill Creek in Lewis Bay, where are you?
 
It's been awhile, but I believe there is a wear ring that fits over the cam on that shaft that spins freely, it runs between the pump arm and the cam lobe. If you spin the shaft at the pulley, you should feel the cam lobe come around.
 
Steve OD said:
yes it does, I did find an old post about changing the oil in the reservoir every year, you have to siphon it out.
Im more concerned about the shaft itself, and the fact I can spin it with my finger, how does it depress the plunger if there is no cam on it?

Scofflaw, I have my own dock in Mill Creek in Lewis Bay, where are you?
Click to expand...
I live close to the Yarmouth House Restaurant on Traders La.
 
Thanks Dlvwill, that's what I was hoping for!

I use traders as my shortcut from the highway, I live off Standish
 
Steve OD said:
Thanks Dlvwill, that's what I was hoping for!

I use traders as my shortcut from the highway, I live off Standish
Click to expand...
You and everyone else...neighbors want speed bumps, A toll booth would be better, defray the cost of gas
 
I had the same issue with same setup. I changed filters, ran the engine while next to it in the ER. I held the choke open and revved the crap out of it , then backed out the jet and screwed back in. this exercise flushed out the bowls , and unscrewing the jet must have dislodged some gunk in there. boat runs perfect now. maybe I just got lucky
 
Steve OD said:
I just tuned up my engines and had the carbs rebuilt. Last fall the starboard engine was not running properly as the carb was corroded, but it would start, just not run well and cut out often.
When I tried to start it up, no fuel was coming into the carb, if I primed it, it started right up.
I took the fuel pump out and it was frozen. So I have a new one on order.
My question is: there was fuel in the area where the shaft and cam are, I assume the pump was leaking. What should be in there? It seems like there should be some type of lubricant.
Also, when I reach in, I can spin the metal collar around the shaft that I believe should have a cam to press on the lever for the pump. Should that spin freely?
Thanks!
Click to expand...

I’m assuming you have the
Mercruiser belt driven mechanical fuel pump/seawater pump set up.
No fuel should be in the cam area. That should be filled with gear oil and changed while servicing your raw water pump impeller. Fuel in that area indicates a failing pump.

The free spinning wheel you noticed..is normal.
 
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