Reply
 
Thread Tools Search this Thread
 
Old 06 October 2017, 16:22   #41
Member
 
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 3,745
I haven't tested WOT with a skiier. I don't think it would be massivley difference, the issue is pulling them out, rather than flat-out.[/QUOTE]

I doubt your skier would be too chuffed hanging on @ 40mph ish while you check wot rpm lol
Your in the middle of the rpm range so switching down to get nearer the upper limit makes sense
__________________
beamishken is offline   Reply With Quote
Old 06 October 2017, 16:36   #42
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 224
Moving from 19" to 17" will make hell of a difference in getting the skier up.
WOT with a skier behind is pretty irrelevant, but a big skier can easily lose you a few mph.

It's worth noting that the size of the skier plus the number & size of skis have a huge bearing on the power required. Then there's technique - If I apply poor technique (deliberately or otherwise) on smallish mono I can prevent a 90Hp engine from pulling me out.
__________________
simonl is offline   Reply With Quote
Old 06 October 2017, 19:24   #43
Member
 
mhb100's Avatar
 
Country: UK - England
Town: Swindon
Boat name: Ballistic
Make: Ballistic
Length: 7m +
Engine: Yam 250 Yam 15
Join Date: May 2007
Posts: 224
Quote:
Originally Posted by simonl View Post
Moving from 19" to 17" will make hell of a difference in getting the skier up.
WOT with a skier behind is pretty irrelevant, but a big skier can easily lose you a few mph.

It's worth noting that the size of the skier plus the number & size of skis have a huge bearing on the power required. Then there's technique - If I apply poor technique (deliberately or otherwise) on smallish mono I can prevent a 90Hp engine from pulling me out.
Dave I gave just read an excellent article which describes exactly your problem. I can't seem to copy the link. Click image for larger version

Name:	Screenshot_20171006-202156.png
Views:	154
Size:	139.8 KB
ID:	122152Click image for larger version

Name:	Screenshot_20171006-202010.png
Views:	156
Size:	139.4 KB
ID:	122153 here is the start of that post.
__________________
mhb100 is offline   Reply With Quote
Old 06 October 2017, 19:39   #44
Member
 
mhb100's Avatar
 
Country: UK - England
Town: Swindon
Boat name: Ballistic
Make: Ballistic
Length: 7m +
Engine: Yam 250 Yam 15
Join Date: May 2007
Posts: 224
Quote:
Originally Posted by mhb100 View Post
Dave I gave just read an excellent article which describes exactly your problem. I can't seem to copy the link. Attachment 122152Attachment 122153 here is the start of that post.
Also checked the prop I had on my Bf90 that rowed skiers fine. It was a laser stainless 20'.Click image for larger version

Name:	DSC_0919.JPG
Views:	140
Size:	51.1 KB
ID:	122154Click image for larger version

Name:	DSC_0917.JPG
Views:	148
Size:	50.4 KB
ID:	122155 confident props not your problem.
__________________
mhb100 is offline   Reply With Quote
Old 07 October 2017, 09:41   #45
Member
 
Country: UK - England
Town: Basingstoke
Make: Ribeye 785s
Length: 8m +
Engine: Honda 225 K3
MMSI: 232018159
Join Date: Oct 2012
Posts: 108
Quote:
Originally Posted by mhb100 View Post
Dave I gave just read an excellent article which describes exactly your problem. I can't seem to copy the link. Attachment 122152Attachment 122153 here is the start of that post.
Yes - this is exactly the issue, and now appears to be a 'well known' flaw.

Their recommendation of just lifting the throttle to ~1600RPM for a little while before slamming it open is exactly what I do. Although I had to laugh at their view that it is a problem seen getting the boat onto a trailer - I can't imagine using sudden blasts of full throttle for this (I tend to glide onto mine with the engine still in low revs to help wind it on).

Anyway, it seems that it is just one of those things to live with, but that a smaller prop would help a bit - so that's my plan... Know and avoid the issue, keep the carbs clean and drop a prop size for skiing.

Thanks all to those contributing - and especially those offing alternative props. As usual you guys are brilliant!
__________________
totallydave is offline   Reply With Quote
Old 07 October 2017, 13:32   #46
Member
 
Last Tango's Avatar
 
Country: UK - Scotland
Town: Denny
Boat name: Highland Bluewater
Length: 6m +
Join Date: Mar 2013
Posts: 1,647
Quote:
Originally Posted by mhb100 View Post
Also checked the prop I had on my Bf90 that rowed skiers fine. It was a laser stainless 20'.Attachment 122154Attachment 122155 confident props not your problem.
Bear in mind that the Laser II is a vented prop so gives you the best of both worlds.... A bit of slip a low speed to let the revs come up and the hydraulic effect stopping it venting a planing speeds means you can still go for the optimum pitch for top speed.
__________________
Last Tango is offline   Reply With Quote
Old 07 October 2017, 13:33   #47
Member
 
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 3,745
Must be a Honda issue across the range the two 50s I did, one already had the anti tamper caps taken off the mixture screws the other I had to remove them but once I had the carbs fully cleaned and adjusted the idle mixtures the engines ran satisfactorily.
A friend of mine used to be a Honda agent and he fitted a 50 to a boat and it had the problem from day one after a lot of time and effort, new carbs altered set up etc Honda eventually gave the customer a new engine under warranty which cured the problem. So maybe some engines are different out of the box.
A vented stainless prop like the laser 11 mentioned would probably help as it induces some slip to allow the engine to spin up I'm surprised the article didn't suggest that rather than mention the standard ally prop allowed some slip.
You may find a smaller prop that allows the engine to rev out further will make little difference to max speed at wot.
People mistakenly think that an engine held back from higher revs is better off than a one that is free to rev to it's max when actually the opposite is true
__________________
beamishken is offline   Reply With Quote
Old 07 October 2017, 14:06   #48
Member
 
Country: UK - England
Town: Basingstoke
Make: Ribeye 785s
Length: 8m +
Engine: Honda 225 K3
MMSI: 232018159
Join Date: Oct 2012
Posts: 108
Quote:
Originally Posted by mhb100 View Post
Also checked the prop I had on my Bf90 that rowed skiers fine. It was a laser stainless 20'.Attachment 122154Attachment 122155 confident props not your problem.
mhb100 - tried to PM you about maybe borrowing the prop but not sure you are getting the messages. Try to PM me and we can exchange email addresses.
__________________
totallydave is offline   Reply With Quote
Reply

Tags
outboard

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT. The time now is 00:37.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.