What fuel should I be running?

[mgs917]

Thank you for the replies so far. I spent the evening reading through the manual, but did not help me much. I really want to learn and be able to work through some of my problems. I was looking at the FCC but I cant get in any position to see anything down there. I even pulled the backseat and the engine compartment dividers.

Lewy2001 I probably wont "jumper the STO" because I dont know what that means. Will you explain it to me if you dont mind?

So it seems like I have a fuel pump shutting off intermittently? Is this a mechanical or electrical issue? Or could it be either or both?

[mgs917]

I did a quick search on the site for gt40. It seems like this is a problem that quite a few gt40 owners have had to face. The general concensus looks like it may be one of the fuel pumps. Thanks airtool and lewy2001 for your suggestions. You both seem to be thinking fuel pump as well. I will try to look into this and keep everyone updated.

[DanielC]

Fuel pump testing
http://www.planetnautique.com/vb3/sh...=Fuel+pressure

[Lewy2001]

Lewy2001 I probably wont "jumper the STO" because I dont know what that means. Will you explain it to me if you dont mind?

So it seems like I have a fuel pump shutting off intermittently? Is this a mechanical or electrical issue? Or could it be either or both?

Jumpering the STO is a diagnostic tool to make both pumps run continuously. It involves jumpering the outside pin of the connector to ground. Normally the ECM (computer) supplies this ground to activate the fuel pumps. Daniel's second picture shows this method.

The problem is that one of your pumps is drawing too much power causing the 15A current limit of the breaker to be exceeded.

[Orlandoguy82]

My GT-40 has the FCC with the little 2" tube that goes from the high pressure pump to fuel rail. This deteriorates after time and needs to be replaced. Look for pinholes or cracks there. You can hook a fuel pressure pump to the rail to see if the pressure drops when it dies off. Also in the fuel tank, well the piece leading into it, there is a anti-siphone/backflow preventer. Make sure its not gummed up and clean with carb cleaner or something like that. Right below that at the top of the tube is a little mesh filter. Its in an awful place as stuff goes up the tube and gets stuck there. This causes mine to just die under high RPM or when pulling. Blow it out if its full of crud. This also means you need to clean out your tank. I too need to do this. I use E10 with sta-bil marine stabilizer.