Starboard Motor useing more fuel than port

[Pkunze]

Hope someone can direct me to a possible solution. My starboard side moter is consuming much more fuel than port, about 30% more. 2004 340, Twin 8.1 V-drives. I use my syncronizer to keep both RPM's even, I see no fuel in the bildge but smell fuel when powering down coming off plane. My throttle controls I do have to push the starboard side further forward than port to keep RPM's in synch but I am assuming this is just an adjustment. Other than that the boat runs and acts fine, any help is appreciated.

PK

 

[jason78]

Do you have a generator? If so are you using it much? I know the genny is on the Starboard side in that 340 so I assume chances are high it pulls off the tank that feeds the Starboard engine. Could this explain the increased fuel usage on that side?

 

[Pkunze]

I do have a genny but dont use it since I'm on a lake. It's definately during cruising

 

[kaz911]

Get a compression test done - it CAN be a bad cylinder. 30% difference is a lot of difference and is something I would get looked at ASAP.

Can you read fuel flow directly from engines? or is it from monitoring tanks?

 

[Crushin It]

When I experienced that I had a plug wire that was not on tight...... Attached it and no more smell of gas, throttles back to even, and consumption normal...

 

[Pkunze]

Kaz, I'm monitoring from Smartcraft and fuel gauges. Everytime I need to fuel up I have to compensate for the heavy use on starboard side. Plus the fuel smell leads to believe i may not be firing right

 

[carterchapman]

Hope someone can direct me to a possible solution. My starboard side moter is consuming much more fuel than port, about 30% more. 2004 340, Twin 8.1 V-drives. I use my syncronizer to keep both RPM's even, I see no fuel in the bildge but smell fuel when powering down coming off plane. My throttle controls I do have to push the starboard side further forward than port to keep RPM's in synch but I am assuming this is just an adjustment. Other than that the boat runs and acts fine, any help is appreciated.

PK

Hi PK,

You and I have identical boats. My Smartcraft shows my port engine uses about 5% more than my stbd engine, yet my refueling shows I use more from the stbd side than port - I just fueled up and took 20 gallons stbd and 15 port - I used the genny about 5-6 hours during the refueling period - thus the increased stbd usage. The one time I was smelling gas fumes at idle, my port engine was "surging" at 2500 RPM. Changed plugs and all smells and surging went away. 5% Smartcraft difference is still present...

 

[Kreole Kid]

If you are not firing properly on all cylinders your motor is missing (mis firing) and it will usually show in your transmission. When at idle in forward gear listen very closely to the engine / transmission noise. You will here a clanking / clunking sound coming from the transmission. If this is your case, change those plugs first, then if it still persists, then change all the wires too.

Here is a link to John Hampton's post about this very problem.
Also good Luck to you:thumbsup:
http://clubsearay.com/showthread.php/26439-How-Why-to-Change-Spark-Plugs-in-8-1-s

 

[mainstream]

Kaz, I'm monitoring from Smartcraft and fuel gauges. Everytime I need to fuel up I have to compensate for the heavy use on starboard side. Plus the fuel smell leads to believe i may not be firing right

Hi pk
I had a similar problem last year when they hooked me to the computer i was fine. When I took a mechanic out he found I was misfiring under load rePlaced wires and plugs all was good i went from .6 mpg to .8 .9 mpg I wOuld start with a scan. I also found smart craft is not actual fuel flow it is an estimation based on rpm. it is off on mIne by about 2 to 4 gallons per fill up.

 

[Jimmy Buoy]

Had a similar issue with my 8.1s. Turned out to be a bad plug that would not fire under load. Once the plugs were replaced the difference was imediately and very noticeable - that was a good day! I was thinking the worst...

 

[Pkunze]

Thanks all who responded. I'll take a quick look at the plugs which should tell me a lot. A compression test may be in my future.

 

[Crushin It]

Pkunze - Did you find the issue and get resolved?

 

[Pkunze]

Talk about a late reply...
Yes, I had a cracked plug on the starboard side motor. replaced all plugs to be sure, ran amazing after. I have since sold the boat and moved to another Sea Ray