Seamouse Posted September 18, 2006 Report Share Posted September 18, 2006 Hi folks, Managed to get SeaMouse onto a local lake for an hour to test out some prop options. Interesting, not least because the lake was short enough to give us maybe 20 seconds at best at full chat before it was time to hit the brakes. Not good when you are watching the rev counter rather than the fast-approaching bank Anyway, the reason to be there was that the Pro Angler won't rev out, either because of the new design prop Evinrude have saddled it with, the possibility that I'd been issued with over-strength trim tabs or the extra weight of the new hull design. It wasn't the tabs. First run with them tied up out of the way and the standard prop gave us same top end of 4200rpm, against the desired target of 4500-5500rpm. Switching from the 'new' Evinrude 17 pitch prop to the original racier 17 pitch saw 4800rpm and that answered the whole question. The old design is way narrower in design, just a shame I can't lay hands on one as direct replacement. However, those rpm are exactly the same as that prop achieves on my friend's e-tec powered 150. He currently uses a 15 pitch Solex(?) prop that gives him 5200rpm and is still available, so I guess that's going to be my next little purchase. The other issue I had was a tendency to list to port under power across a sea. That wasn't the tabs either (innocent, M'Lud) as even on a flat lake it was a little port-biased, most noticeable oddly enough when you killed the throttle. Torque steer?? Anyway, I'm a much happier bunny now as I can reinstate the tabs, purchase a prop with confidence and hopefully get out there and do some fishing! Steve Reinstatement of the trim tabs at this point may have trimmed 50-100rpm of the top end at best but I wasn't really able to study the instruments that carefully Quote Link to comment Share on other sites More sharing options...
Paul J Posted September 18, 2006 Report Share Posted September 18, 2006 Steve, let us know how it works out as im considering doing the same. Im running an etec 60 pushing a 17ft boston whaler ( approx 1500lbs loaded) and achieving 29knts@ 5000. I'd like to get to 5500 and may well go down from 17" to 15" prop Thanks Paul Quote Link to comment Share on other sites More sharing options...
Afishionado Posted September 18, 2006 Report Share Posted September 18, 2006 Torque steering or rather the removal of the torque effect when you throttle down is probably the culprit. You could try moving the little vertical tab sticking down from the underside of the cavitation plate to compensate for it, but it is a question of trial and error to get it right. Mad Mike Quote Link to comment Share on other sites More sharing options...
Seamouse Posted September 18, 2006 Author Report Share Posted September 18, 2006 Steve, let us know how it works out as im considering doing the same. Im running an etec 60 pushing a 17ft boston whaler ( approx 1500lbs loaded) and achieving 29knts@ 5000. I'd like to get to 5500 and may well go down from 17" to 15" prop Thanks Paul Hi Paul, If you've got the older prop design, you can't get it any more (I'm told) so you'd be looking at changing design as well as pitch. Can't miss them visually, the old design has a narrow, pointed blade and the new ones have a broad, open blade similar to a Bigfoot prop. They only appeared on e-tecs early this year. I'm not an expert at all, but 5000rpm is slap in the middle of the recommended range and 29 knots from 60hp would be good for a Warrior-weight boat. I'd say your prop is already pretty damn near perfect?? Even if a 15" allows you to max on revs, it wouldn't necessarily increase top speed? Steve Quote Link to comment Share on other sites More sharing options...
Seamouse Posted September 18, 2006 Author Report Share Posted September 18, 2006 Torque steering or rather the removal of the torque effect when you throttle down is probably the culprit. You could try moving the little vertical tab sticking down from the underside of the cavitation plate to compensate for it Hi Mike, I was thinking that was the next path to go down, since the trim tabs didn't seem to be at fault. Question is, if the boat seems to want to drop to port, do I turn the cavitation trim tab to point to port or to starboard?? Steve Quote Link to comment Share on other sites More sharing options...
Afishionado Posted September 18, 2006 Report Share Posted September 18, 2006 HEhe! Last year we had a HUGE thread on this subject, cos some of these little trim tabs pivot on the front (leading edge) and some from the middle and some from the trailing edge, and to make matters worse it's different if you visualise looking from the leading edge backwards or from the trailing edge forwards So .... Looking forwards standing behind the O/B and talking about the trailing (back edge) of the trim tab ......... Moveing the TRAILING edge to the RIGHT will induce a right turn at the bow. Moving the trailing edge to the LEFT will induce a left turn at the bow. A small change each time is best. Another thought........ Some manufacturers make these little tabs act as the scrificial anode making them out of a Zinc alloy. If the motor is left immersed in sea water or is quite old then the thing may have desolved away to nowt?? Mad Mike Quote Link to comment Share on other sites More sharing options...
Seamouse Posted September 18, 2006 Author Report Share Posted September 18, 2006 Moveing the TRAILING edge to the RIGHT will induce a right turn at the bow. Moving the trailing edge to the LEFT will induce a left turn at the bow. ... Some manufacturers make these little tabs act as the scrificial anode making them out of a Zinc alloy. If the motor is left immersed in sea water or is quite old then the thing may have desolved away to nowt?? Cheers Mike, that'll do me. I'll have a play over the next few trips if I get chance. Brand new engine so tab erosion certainly isn't the issue. Steve Quote Link to comment Share on other sites More sharing options...
britboard Posted September 18, 2006 Report Share Posted September 18, 2006 (edited) You could try moving the little vertical tab sticking down from the underside of the cavitation plate to compensate for it I thought that moving the trim tab on the engine was only to stop steering drag, i may be wrong please correct me if i am Also mercury quotes moving the tab the other way round, see picture. Simon L Edited September 18, 2006 by britboard Quote Link to comment Share on other sites More sharing options...
Afishionado Posted September 18, 2006 Report Share Posted September 18, 2006 You could try moving the little vertical tab sticking down from the underside of the cavitation plate to compensate for it I thought that moving the trim tab on the engine was only to stop steering drag, i may be wrong please correct me if i am Also mercury quotes moving the tab the other way round, see picture. Simon L Oh gawd here we go again Anyone want to start? Mad Mike Quote Link to comment Share on other sites More sharing options...
Paul D Posted September 18, 2006 Report Share Posted September 18, 2006 Mike, Yes - I will start If the steering is pulling to the right ( ie. Boat tries to turn right on its own accord ) then turn the trim tab such that the trailing edge of the tab ( ie. The bit furthest from the prop and nearest the back of the outboard ) is twisted to the right ( ie. Move the rear of the tab towards the direction that the boat is pulling ). On my E-Tec you can only turn the trim tab in this direction and this is because they know the pull will be to the right ( as in starboard ) due to prop steer. My boat pulled strongly to the right until I moved the tab. Beware a small movement has a dramatic effect. Quote Link to comment Share on other sites More sharing options...
Paul J Posted October 8, 2006 Report Share Posted October 8, 2006 i've tested the 15"prop now albeit in some pretty sloppy conditions. My rev range is 5500- 6000 with 60hp's kicking in at 5750. Lots of pluses with the new prop like getting quicker up on the plan but i've lost a couple of knts off the top speed eg:27 instead of 29- not a big deal. The revs top out at 6200 which is over the top range, can this cause damage? Will it drop when i go to two people on board? Cheers PJ Quote Link to comment Share on other sites More sharing options...
duncan Posted October 8, 2006 Report Share Posted October 8, 2006 am going to suggest that you are now underpropped - somehow! how you have managed to go from 5500 to 6200 (in sloppy conditions) beats me unless the current test was no gear, no fuel and you have been on a diet I would run the old prop instead and save this one for when you want to go our in the summer 4 up and loaded with gear! Quote Link to comment Share on other sites More sharing options...
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