Mechaical fuel pump

C

carver 2557

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Went to do my spring start up, and no go. Boat wouldn't fire. It fires as long as I put fuel in the carb. boat has lots of gas in it. My fuel line goes from my talk to my water separating filter, then to the fuel pump and then to the carb. I checked and the water separating filter was full of fuel. I'm thinking that if the pump was working the fuel should have been sucked out of the filter?. I removed the fuel pump and the arm on it is almost impossible to push. I know it will take lots of pressure to push it, but it seems tight. Am I correct in thinking the fuel should have been sucked from the water separating filter if it was working. Sounds like the fuel pump might be pooched???
 
Do you have a filter at the carb intake? If so, did you check this and any other filters?
 
Did you check for accelerator pump squirt in the carb throat. Did the gas in the separator filter smell strong gassy /fresh?
Was there any fuel in the suction line at the pump when you removed it? Remember a suction air leak, say at the filter gasket could prevent fuel from being sucked from the filter.
I believe the lever can be a bit difficult to move. And on a stored boat's old pump, crank oil may lube it better after the engine runs. Unless the pump lever is stuck in the down position or there was leaked fuel in the sight hose to the carb j-valve, I'd think odds may be low the pump is bad. But if you suspect it this would be a handy time to replace it.

You can check (installed) pump action by disconnecting the fuel line at the carb inlet , securing a plastic bag over the line end or a hose leading into a suitable container , and briefly cranking the engine to check if any gas comes out. If so, the carb float valve could be stuck closed.

The fuel tank valve is open and any crossover valve is closed, yes?

Here's an internal look and overview:
http://www.aa1car.com/library/fuel_pump_mechanical.htm

If it looks like the pump is really not pumping, make sure the pump actuating rod inside the block can move up & down freely with the cam in up position. I believe they've been known to get jammed in an up position.

If you replace, of course only use a marine pump with leak/sight-hose fitting.
 
Accelerator pump didn't squirt gas...
Gas in separator filter smelt strong gassy smell...
No fuel in suction line at pump...
No fuel shut off valves in boat...
I think at this point as I have the pump off, I will take it to my mechanic to see if it can be repaired, and if not might as well change it. It looks original and the boat is a 1989 vintage...
 
When I changed out the mechanical pumps on my old Slickcraft 302's, the pump was stiff but movable by hand. If I remember correctly, a new one wasn't crazy expensive...
 
Yeah, shouldn't be very expensive. Sandy covered pretty much everything. If you try pushing the pump lever, it should make loud pumping and sucking sound from the diaphram if it's good.

There's a bolt hole on the front of the block that corresponds(lines up) with the pumps push rod. It's used to hold the push rod in the farthest IN position if tightened down just enuff to hold the rod. Engine has to be rotated so the lobe for the fuel pump is in the open position(not pushing the pump lever). made for easy install. Bolt has to be backed off after pump installed so no longer in contact with push rod. If bolt is in contact with push rod, it could be the cause of pump not working.
 
Holding this push rod was going to be an issue when I install the new pump until you told me about this bolt. I will definitely look for it tomorrow.
I'm hoping that my engine has one of these bolts...
 
Some people just use petroleum jelly or grease to temporarily hold the rod in the up position for pump installation, but Charlie's bolt trick is more reliable if there isn't too much in the way.
 
I couldn't find that bolt, so I used a bent hacksaw blade to hold the rod up. Worked very well...Pump on and still no fuel pumping. Now I have to trace back to the tank..I'm going to try hooking a temporary line from a bottle to the pump, just to make sure that its working..
 
You might want to check the anti-syphon valve as well as the gas tank pick up tube strainer. I have had both a clogged AS valve and a clogged strainer on the end of the pick up tube. Drove me nuts trying to diagnose until I pulled both pieces.
 
Is this a small block chevy engine? They all have the bolt...or rather the threaded bolt hole. You might have to use your own bolt. The push rod runs down at roughly a 45^ angle. The bolt/hole will line up with this angle.

I've used grease or hacksaw blade or a coil of wire but none are as good or fast as the bolt.
 
Found the bolt hole, and that method works very well. thanks for the tips all...She runs. tried everything I could think of and no go. had the fuel pump rebuilt and still no gas. Took the fuel pump off and filled it with gas to prime it, and she fired right up. I'm back in the boating business this summer...
 
Perseverance wins out! Waytogo and happy boating!

Generally if the pump has no prime, just dribbling a little fresh gas down the carb throat and cranking once or twice will allow the pump to prime sufficiently if the primary filter is good and full and there are no restrictions or air leaks. That also helps overcome a sticky anti-siphon valve since it allows the dry pump to build a lot more suction.
But I think you tried that early on.
 
Congrats!!

If you want to be a boater(not just a boat owner) ya gotta have that stubborn streak that won't let you give up.
 
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