How do you pressure / vacuum test a 5.7L Mercruiser ?

[MarkSee]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

That's seems like some right good advice there mate in his situation.
If I ever seem to be in the same "boat", please free to tell me the same thing as it means I've gone :topsy_turvy:.

Mark

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

The boat is seaworthy !! I go offshore fishing in 3-6 foot seas in 100-150 Ft in depth of water and she always preformed outstanding. these problems that i have listed have just occurred and i have not went out yet with these problems. The fact that you say that my boat has a manual pump is not true . every time when i turn the key and pump some gas into the carburetor i hear the pump kick on and send fuel to the carburetor. And the batteries are really dead i know know as a fact that my alternator bearing is bad . The boat does stall out sometimes on the batteries that is why i am not going out till i resolve the problem !!

 

[thumpar]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

Well it looks like something is not factory if there is a pump coming on. An electric boat fuel pump should only come on when the engine is cranking or running.

 

[achris]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

If someone has added an electric pump and you hear it come on without the engine running... This is VERY dangerous. What it means is there is no oil pressure switch in the electric pump circuit. If something goes wrong with the fuel system you have the potential to pump the entire contents of the fuel-tank into the bilge...

I'm currently helping someone else with very similar problems. His boat has been 'modified' by someone with scant regard for safety too... Maybe you should read his thread. I have a couple of examples in there about how small things can cause big trouble, and people die...

You can start by reading this post, but the whole thread is worth having a read of...

http://forums.iboats.com/mercruiser...s/mercruiser-4-3-leak-628929.html#post4397515

Chris........

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

Ok guys so i have went and did some serious maintenance on my boat . I have found out that my boat is equip with a electric fuel pump and its is working because i hear it go on !!

 

[achris]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

Have you physically located this electric pump? Once you do, follow the wires back, they should go to an oil pressure switch... If they don't go to a switch, but go straight to the switched 12V, then you need to change it around, so it does go to an oil pressure switch... Also check to see if the old mechanical pump is still in place, or if the block aperture has been closed off.

This is how the wiring for an electric pump in a boat should look. The principle is that the pump will only get power while the oil pressure is up (engine running) or the starter-motor is running (engine cranking). Should the engine stall, then the oil pressure will drop, the switch opens, the pump stops running. This is a safety feature so you can't fill the bilge of the boat with fuel from a flooding carb or broken fuel line....
:boom:

If you hear the pump when you turn the key to ON, it's wired incorrectly...

So far, I don't think you have been asked for an engine serial number... Could you provide that please. It will help a lot in determining what you should have on that engine... If you need to know where to look for the serial number, click HERE.

Chris......

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

Have you physically located this electric pump? Once you do, follow the wires back, they should go to an oil pressure switch... If they don't go to a switch, but go straight to the switched 12V, then you need to change it around, so it does go to an oil pressure switch... Also check to see if the old mechanical pump is still in place, or if the block aperture has been closed off.

This is how the wiring for an electric pump in a boat should look. The principle is that the pump will only get power while the oil pressure is up (engine running) or the starter-motor is running (engine cranking). Should the engine stall, then the oil pressure will drop, the switch opens, the pump stops running. This is a safety feature so you can't fill the bilge of the boat with fuel from a flooding carb or broken fuel line....
:boom:

If you hear the pump when you turn the key to ON, it's wired incorrectly...

So far, I don't think you have been asked for an engine serial number... Could you provide that please. It will help a lot in determining what you should have on that engine... If you need to know where to look for the serial number, click HERE.

Chris......

Well the pump olny turns on when there is oil pressure ! it does not turn on when the key is on ,

 

[achris]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

Well the pump only turns on when there is oil pressure ! it does not turn on when the key is on ,

Is this a question or a statement?

 

[thumpar]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

The fuel pump should turn on while the engine is cranking (starter motor) also.

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

statment . I have checked and tested it . It works like it should !

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?

yes it does that !

 

[FixIt4Life]

Re: How do you pressure / vacuum test a 5.7L Mercruiser ?



These are my spark plugs . Some of them not all . I have sprayed everywhere where i thought a leak might be coming from and nothing changed , so i assume there is no vacuum leak !