opinions on 4 blade props
hi guys
i have just tried a s/s mecury 4blade prop on my 200 etec which is on the back of a 655 southwind (did have a s/s 3blade reble) i was chasing a few more revs as the current prop wont let the engine rev to its max(loading up to much we assumed) and was hoping for some fuel saving as well.
yes they were both 17"
so the plan was to run it for testing on a full day fishing out deep as a normally would.
first test was last sat night, i noticed from the word go it was pulling more revs at the same speed.
wot it pulled a extra 500-600 rpm at the same speed, which is nearly were we needed to be, so we thought all is looking good and
it looks like the load has come off the engine????
until i refilled the boat today and have found out the fuel usage has gone up, with me covering a bit over half the distance i would normaly do for the same fuel amount....which when i look at it now.....more revs for same speed = more fuel
this supprized me greatly and i was wondering if anyone else has experimented with 3-4blade props.
luv to here from anyone.
cheers ron
holth
Posts: 812
Date Joined: 09/10/06
Hey ron , a 3 blade rebel is
Hey ron , a 3 blade rebel is the go on most etecs that are used offshore, l see yourve been running a 17" Whats the current WOT rpms with this prop?, dropping to a 15" will pick you up those extra Rpms. If not the 4 blade cyclone.
Paul
Brucesta
Posts: 1721
Date Joined: 29/05/09
i went from a 3 blade 17 inch
i went from a 3 blade 17 inch prop to a 4 blade 18 inch prop, dropped 2-3knots WOT now getting 41knots at 5600rpm which is bloody fast enough if you ask me but i got fuel saving, 3 blade 17 inch ran at 20 knots at 4200rpm and 25 knots at 45-600rpm. Now with the 4 blade 18 inch jobbie i cruise 20 knots at 3900rpm and 26 knots at 4200rpm then 30-1knots at 4500rpm. Slight fuel saving in a way but i'm getting places faster as i sit on 26-30 knots if possible on the way out but if i had to play economy i can drop back to 20 knots and use only 26L per hour.
Boat is a Cruisecraft Oustider 625 with a 200hp Yamaha 4 Stroke.
Las Vegas - Rolling the dice and trying your luck. 1M+ Barra summer target. 100kg Black Marlin winter target
fisho-ron
Posts: 2539
Date Joined: 26/09/09
thanks guys funny that, i
thanks guys
funny that, i asked my boat mech today if a 18" 4 blade would be better, i dont think he had one, only for bigger size engines.
if anybody has a 18" 4 blade to suit a 200etec i can borrow for testing would be great, dont want to fork out the coin for no reason
cheers guys
edit; with my 3 blade im only getting 39knts at 5000rpm, engine not reving to its max, used to get 44knts out of the old 200 yammy
nev
Posts: 193
Date Joined: 04/02/09
have a look
at the Evinrude Etec owners group fisho -ron. Lots of information on propping an Etec correctly.Correct WOT revs and engine height is very important and it is a good source of info... cheers
fisho-ron
Posts: 2539
Date Joined: 26/09/09
yeah mate, had a look.i am
yeah mate, had a look.
i am going to check my engine hieght tomorow while im out, needs to be checked at speed.
then if thats right will look into props some more.
cheers ron
holth
Posts: 812
Date Joined: 09/10/06
geez Ron, you must be burning
geez Ron, you must be burning some serious oil being so overpropped.
When l had my 150 it was propped with a 17 and only pulled 5000 at WOT, when propped right the motor sounded and ran so much better.
An 18 wont help you mate, ask the guys at chivers if you can try before you buy, a 15 rebel or 15 cyclone.
fisho-ron
Posts: 2539
Date Joined: 26/09/09
just check with mech mate, he
just check with mech mate, he seems to think 15 will be to small and give me the same response as the 4 blade, more revs for the same speed.
holth
Posts: 812
Date Joined: 09/10/06
200/300 rpm per 1 inch of
200/300 rpm per 1 inch of pitch. a 15 should be perfect mate. but this is just my opinion.
have a look here www.etecownersgroup.com
Andy
Posts: 522
Date Joined: 08/10/05
prop
what was the 4 blade a rev4 or trophy
fisho-ron
Posts: 2539
Date Joined: 26/09/09
mercury mate
mercury mate
paula8519
Posts: 101
Date Joined: 09/03/10
four blade prop
Surprised to see your result, i would have thought you would have improved consumption. I run a 200hp opti merc 2010 model on a FIBRE GLASS reef runner 6.2 meter, its a heavy rig when you put 4 divers 8 scuba tanks and the rest of the gear on board scuba , prob 1.6 ton with fuel. Initially i ran a 3 blade vengence 17 pitch sst merc prop, then changed to a 4 blade sst offshore merc prop of 15 pitch , this combo gives me 20 liters per hour at 4000 revs, i pull 5850 at WOT, I FIND THAT running at the 4000 rev band is the most economical , i have a merc moniter which gives me the best fuel optimisation taking into account load, trim, revs etc it works a treat. My experience with the 4 blade is one of better bow lift , better tracking, but heavier steering. The savings in fuel are significant. The prop excells in rough water ,hangs on with no prop ventilation. The merc is a noisy motor but sips fuel sweetly in the mid range.
paul a