twin merc 470's port sucking up gas the starboard using better then half as much????

[max2fastboat]

Hi again all well I just ran out of gas in my port engine again today second time out. put 10 gallon each side (motors are set up with each has its own tank) had a nice ride with the bride in to boston from Weymouth Fore River, littel bit around the harbor and home we go. Half way back
the old lady is humming along (the boat not the bride):facepalm: and the port engine stops. can't be more then 10 miles each way, any way how should I go about getting to the bottom of this? Any help is welcomed.

Thanks All

 

[EddiePetty]

Re: twin merc 470's port sucking up gas the starboard using better then half as much?

Are you sure the port engine actually consumed the fuel or is it simply failing to pick up the majority of the fuel in the tank???

I would first FILL both tanks (assuming they are of equal capacity) and note the quanity each tank takes. My bet is that there is still a quanity of fuel in the port tank that couldn't be picked up (due to positioning of the pickup, perforated pickup tube, short pickup tube, etc).

 

[max2fastboat]

Re: twin merc 470's port sucking up gas the starboard using better then half as much?

the port tank is bone dry, droped a stick in after banging on it, not a drop. The starboard tank has about 5" left in it

 

[jayrodoh]

Re: twin merc 470's port sucking up gas the starboard using better then half as much?

Both running the same RPM? When you put the 10 gallons in each, were they both the same level/empty to begin with?

How long have you had the boat (maintenance history)? Same spec engines? Pull your plugs, look for signs of running rich. Check the oil for signs of gas in it (bad fuel pump).

 

[Scott Danforth]

Re: twin merc 470's port sucking up gas the starboard using better then half as much?

^+1, also look for a leak, check the thermostats. you will find the issue

 

[max2fastboat]

Re: twin merc 470's port sucking up gas the starboard using better then half as much?

1. first year with boat same RPM by ear not shore if the tacks are working right. what am i looking for
on the plugs, what are the signs on with the thermostats???? I thought the port tank had more gas then the
starboard tank. no leaks from the tank or lines that I can see or smell any gas.