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Hill Marine Props and Fuel Consumption
YYZRC
Member Posts: 4,907 ✭✭✭✭✭
My starboard motor uses 15L/hr more than Port whilst at 4000+ rpm. These readings are from VesselView and confirmed by actual tank drain. I also have the throttle open more on the starboard side to sync with port.
Edit: it was the props - both sets purchased brand new and never repaired.
2008 350 EC on Georgian Bay
Post edited by YYZRC on
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You have 3 valve switches on your fuel lines to the engines. The center one should be off and the two sides should be open. This allows each motor to feed off of each individual tank. If the center one is open (as well as the 2 sides), it may feed more off of one side than the other.
Dream 'Inn III -- 2008 400 Express
My starboard motor always burned more fuel than port but (about 5 lph at 4000 rpm) but it got much worse after I clipped the rock coming out of Frying Pan. I have brand new props but I wonder if maybe I bent the prop shaft a bit. Will check it out at haul out as I need to have the skeg fixed.
It does sound like a lifter. A leak on the inner exhaust manifolds (corrosion you cant see) will drain back into the cylinder... just a little at first and then progressively worse... its well capable of collapsing a lifter if water (especially condensed steam collecting atop a once/recently hot piston) is present in the cylinder... the first thing to go with that would be a lifter... then a bent lifter rod.. then a blown head gasket... then a bent connecting rod or windowed piston....
The extra fuel, though, accompanied by the lifter tick could just as easily be a skipped timing chain- a degree or two out of mechanical (valve event/crank position) giving same symptoms and certainly capable of collapsing a lifter.
How many hours on the motors? Manifolds? Timing chains usually show their weakness early and if they check out you get a good long life out of them... manifolds could be fine- or not- the easiest tell for them is rust on plug...
Get a good vacuum gauge- an analog one.. Google for vacuum signals and charts, and what they mean. You'll find out quicker doing that than anything else.
Both motors run same temp (indicated 160 degrees). The motors have 190 hours on them and risers/manifolds are original. Fresh water boat always. No rust on plugs.
PC BYC, Holland, MI
You can do a cheap diagnostic... redneck stethoscope- long handled screwdriver and put your ear to the end of the handle... could the ticking be coming from the sea pump? Put the end on the intake manifold and work around the perimeter to determine if it's a lifter and which one.
@Black_Diamond is smart fella- a ujoint in your drive or the cardian connection could be worn, and they tick, too... it would do it in neutral as well as in gear and it too would increase with RPM.
IF it's a lifter, and knowing the location via the stethoscope, you'll have it narrowed down to one cylinder- but may not know if it's exhaust or intake.
Pull the covers on that bank and see which rocker wobbles a little. They shouldn't wobbles at all.