Detroit 12v92 DEDEC fuel comsumption diff.

[northshoreone]

I have a fuel consumption diff. From engine to engine on my 12v92s. I purchased the boat a bit over a year ago and at sea trial.... and ever since...the port engine burns the same as the starboard up to about 1,000 rpms and at wide open 100% load. From above 1,000 rpms the port engine starts burning more than the starboard by 10 gallons per hour. Both engines were rebuilt about 1,100 hrs ago at about 1,100 hours......I had the props pulled and scaned.... no problems there. Both run very close to the same temp. Underway.....Oil was sent out for analysis.....no issues found. I had one mechanic say it could be injectors not functioning correctly on that engine. I would appreciate any insight that you all may have on this issue.
Oh, on the sea trial the port engine toped out at 2,110 rpms and the starboard one at 2,240 rpms......it almost appears that the port engine is under more load for some reason......out of the water both props take about the same effort to turn by hand.....i'm at a loss for the higher fuel burn and lower rpms......

 

[capttonyf]

Are the fuel scans working properly? Maybe the engines are fine and it's just DDEC fuel scan issue. Did you try topping off tanks and running each engine on a different tank for a few hours? Then refill to see if there actually is a difference?

 

[chris piazza]

Sound like the load is more on one engine, probably a bad prop,

Chris

 

[capttonyf]

It could be a bad prop, but you would more than likely see Higher Temps and maybe a little smoke from that engine. Even if water temps are the same I would bet you stack teps are alot hotter. If your boat doesnt have stack pyrometers have a mechinic check it manually while underway.

 

[northshoreone]

I have recorded engine temps over 1200 miles at the terbos, exhaust, transmission and other locations with a heat gun. The engine with the higher burn rate is only about two degrees hotter. That engine also emits no smoke.. I have now switched the DDEC boxes from one to the other engine.....I will return to the boat in a few weeks to run it again and see if anything changes. Props have been checked and are the same......
Thanks for the feed back....will keep you all posted as to what i find out....