Volvo Penta 5.7Gi Compression Test?

[VIPNiSS]

I am looking at purchasing a boat this Saturday and it has a Penta 5.7Gi motor with a SX Stern.

I am wanting to perform a compression test on it before I purchase it. What is the best way to do a compression test on this motor? I have read so many different ways and I think I have just confused myself.

From what I understand so far these are the steps that should be taken. Please correct/add if I am wrong.

Throttle should be wide open
Unplug all spark plug wires
Take out all the plugs
Screw in the compression test gauge
Turn it over 3-5 times until it gets maximum compression on gauge
Repeat on all cylinders

 

[Don S]

Re: Volvo Penta 5.7Gi Compression Test?

What makes you think the boat owner or dealer is going to allow you to take parts off the engine and do a compression test? I know I wouldn't. You screw up the threads on one spark plug or misplace on plug wire, it's YOUR fault. Do you want that?
I assume you know how to disable the ignition and fuel pumps to do the test?

 

[VIPNiSS]

Re: Volvo Penta 5.7Gi Compression Test?

I did already ask and he was really confident about this boat. He said I am more than welcomed to.

Ignition I am not sure but as far as fuel pump goes can you pull the fuse like you do in a car?

 

[Don S]

Re: Volvo Penta 5.7Gi Compression Test?

Not sure which engine model you are going after, but without ignition, the injectors won't fire on fuel injected engine. Here is how to diable the ignition and the fuel system.

View attachment Disabling Ignition Systems.pdf

 

[VIPNiSS]

Re: Volvo Penta 5.7Gi Compression Test?

Thx Don... I know its a 5.7Gi fuel injected

 

[Don S]

Re: Volvo Penta 5.7Gi Compression Test?

The Gi only indicates it's a GM engine and fuel injected. Not what year or model it is or anything else. Without a full model number or serial number, it's hard to say what it is.

 

[VIPNiSS]

Re: Volvo Penta 5.7Gi Compression Test?

hi Don.. its a Gi-E.. serial is 4012116275