gm305 oil,fuel pump question

[sarantis]

1)Do you know if BP Vanellus C4 multi-purpose for both gas and diesel engines SAE20-50 is suitable for gm305 year 1978?A mechanic told me that any oil fater than SAE20-40 is dangerous to get the hydraulics valves stuck due to poor oil flow.
2)Next to the mechanical fuel pump there is a trasparent cup with a label inside it saying if you see gas inside it change the fuel pump.This cup has inside one or two drops of gas.Because i have a problem with my boat(after runinig at high RPM for 3-4 minutes sudenly it goes off and it starts again after some minutes and no problem if i continue at low RPM ,carburetor rebuilt,)i want to check the fuel pump.Is this serviceable or since you open it you have to replace it?
Thanks in advance for any replies

 

[sarantis]

Re: gm305 oil,fuel pump question

Sory,i think it's not mechanical pump but in-line.

 

[sarantis]

Re: gm305 oil,fuel pump question

Any opinions about the oil? About the fuel problem i 'll check first the tank.

 

[Robj]

Re: gm305 oil,fuel pump question

On that vintage car engines we used to run 10W30 or if was old and tired, maybe 15W40. I am not sure if your mechanic is right, but personally I would not run 20W50 in a chev V8. Yes you could starve the back end if you use too thick oil, but I am not sure if 20W50 would do it. Save the thicker stuff for the 4 bangers.

Regarding fuel in the sight glass, it says that if there is fuel present to replace the pump. While I have not seen your pump, it sounds like the diaphram is leading and you should replace the pump. Make sure you replace it with a marine pump.

Have a great day,

Rob.

 

[sarantis]

Re: gm305 oil,fuel pump question

Thank you Rob.Since the two three drops of fuel may sit there some years i prefer to check the fuel tank first.Any other opinions about the oil?