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A puzzler with a moral at the end
Posted: Sun Jul 01, 2012 1:49 pm
by rbcool
My dock neighbor has a huge houseboat with
twin 305 volvo gas, carb ca1996
volvo/penta duo-prop outdrives
While coming back from Daltaville last week he couldn't get up on top, 8kt max
Port engine was maxed at 3000 rpm, Strbd 4900
While in the bay he changed all fuel filters on the port engine, including checking the one at the carb.
Nothing changed and he cruised back at 8kts
We had a pow-wow at the dock and several suggestions were given but he was in too pissy of a mood to listen
This weekend we figured out the problem and she's purring now.
Any guesses as to what the problem was??
I'll give the answer later
Ron
Posted: Sun Jul 01, 2012 3:48 pm
by EM63
Something has disturbed the throttle cable
--
Greetings - Heiner
Posted: Sun Jul 01, 2012 4:01 pm
by prowlersfish
Even at 3000 & 4900 rpm she should be on top . assuming it was fine shortly before , I would think the engine turning 4900 rpm had a slipping drive train / prop issue .
Posted: Sun Jul 01, 2012 4:20 pm
by EM63
Give me a pic of this 'huge houseboat'
--
Greetings - Heiner
Posted: Sun Jul 01, 2012 8:31 pm
by alexander38
crab pot...
Posted: Sun Jul 01, 2012 9:04 pm
by jefflaw35
I was thinking panty hose around the prop. Moral "dont use the boat, to off the wifey" but crab pot is more realistic....
Posted: Sun Jul 01, 2012 11:38 pm
by Torcan
Pull in the anchor
Don't depend on others to do your job for you.
Posted: Mon Jul 02, 2012 7:14 am
by ready123
Fuel tank vent blocked? Stuck float in carb? Plugged main jets?
Posted: Mon Jul 02, 2012 8:22 am
by prowlersfish
I belive the issue is on the motor turning 4900 rpm NOT the one turning less .
Posted: Mon Jul 02, 2012 8:43 am
by Stripermann2
prowlersfish wrote:I belive the issue is on the motor turning 4900 rpm NOT the one turning less .
+1. Let's see, house boat, twin 5.0, Volvo outdrives with duoprops...
Over-reving on one engine. hmmm... blown lower unit, spun hub/prop assembly, missing or damaged prop assembly!
Posted: Mon Jul 02, 2012 12:40 pm
by captainmaniac
Prop sequence reversed (ie big and small swapped), or one of props in the pair on each drive mounted backwards (so one prop is in forward, the other is in reverse).
Posted: Mon Jul 02, 2012 4:04 pm
by trojanmanXS
oh this outa be interesting,,,
Posted: Mon Jul 02, 2012 6:39 pm
by tsawyer
Big wife on the bow?
Posted: Mon Jul 02, 2012 8:33 pm
by Big D
This can go on for a while, there are a range of things that will cause those symptoms from the simplest to the most complicated. My motto for diagnosis is to start with the simple things first, ie; make sure something was actually plugged in before you jump to conclusions and start tearing things apart!
Posted: Mon Jul 02, 2012 9:08 pm
by Big D
captainmaniac wrote:Prop sequence reversed (ie big and small swapped)...
Can't be done; forward prop mounts on a much bigger shaft than the aft prop. Never tried facing each prop the wrong way but suspect you would lock up the props becasue the forward facing edge of each hub is countersunk. This allows the forward prop to slide into the gearcase and the aft prop to slide into the back of the forward prop otherwise they would lock on each other. You're thinking out of the box though, and sometimes that's exactly what you need to solve such issues.