Manual Lever on Fuel Lifting Pump Ineffective

[dkerphunter]

Hello, After changing fuel filters on our Yanmar 3GM30F, I tried to bleed the system by loosening the bleed screw on the secondary pump, and actuating the manual lever on the lifting pump. Nothing comes out. If I crank the engine, which also actuates the pump, it seems to work. It's a new pump. Any ideas as to why I can't bleed the fuel with the manual lever? Thanks!

 

[Allan12210]

On mine, I have to push the lever down through what seems to be really easy and then push some more where it is stiffer but actually works. The pumping part of the stroke is very small on these pumps.

I also added a squeeze bulb to my fuel line just before my Racor that makes bleeding real easy.

 

[dkerphunter]

I remember that behavior now from my last pump. I'll try again!

 

[Capt jgw]

If the internal actuating lever is up on its cam, the manual lever won't work at all. Rotate the engine 1/4 turn and it's back to normal. A squeeze ball works a lot better, just watch for air leaks on its connections.

 

[kloudie1]

Yup.. Rotate the crankshaft a little at a time .. may take a couple of moves... and try the pump each stop.. you can put a mark on the crank pulley once you have it where it works.. next time it is either on the mark or one rev away from working... Cam is at half crank rotation, so 1/4 turn of crank is 1/8 turn of the cam..

 

[pateco]

I second the squeeze bulb

 

[weinie]

my 3ym20 will start and run for a few seconds after i change the filters. It's enough to prime most of the system and then i can bleed it with the lever. Otherwise, i could pump all day and not get anything. Took me a while to figure out what was going on when i first got the boat ... now i do it all the time.

 

[dkerphunter]

Several posts mention cranking the engine a partial turn. I assume this doesn’t mean with the starter motor. That wouldn’t be precise. Foregive my ignorance but how is this done manually on a 3GM30F? And wouldn’t you have to release compression to be able to do this (even if you knew how)!

 

[Jerry Clark H356 SV Persi]

I agree with the squeeze bulb. The lift pump eventually gets some fuel over there, but it takes a lot of pumps.

 

[Allan12210]

And twice I have ended up with a lot of water in my fuel tank. That's how I can tell it's time to replace the fill cap gasket. Funny how that works. Anyway, with the squeeze bulb I can move a 1/2 gallon of water out of the bottom of the tank in about 1 minute. Try that with that little manual pump lever. I know an electric fuel pump is faster, but I went with the squeeze bulb as it doesn't require wiring and just draws through with the mechanical lift pump.

 

[Mark Maulden]

Maybe a little change of preventive maintenance procedures??

 

[Allan12210]

Maybe a little change of preventive maintenance procedures??

That too.

 

[kloudie1]

With the decompression levers engaged, the engine can be rotated by hand or with a socket wrench on the crankshaft pulley nut.