Reply
 
Thread Tools Search this Thread
 
Old 08 August 2008, 16:43   #11
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
Uprating Evinrude's 10 to 15 HP

Reading profiles, posts, most Ribnetters are using Yamaha, Suzuki and Tohatsu engines, but least of all EvinJon's, in the portable range, so if any sibber out there wishes to make this tricky uprate to his own engine, this is the correct factory procedure.

Short story:
Bought a brand new second hand Evi 9.9 HP 2 strokes engine including it's service & parts manuals and a OMC 305 strongan sib made by Zodiac in the year 1996. Years latter, sold the OMC 305 changed to larger/wider Quicksilver 330, but retained the 9.9 engine. 3 years ago changed to a Sea Rider 360 much wider/longer than the 330 but in complete doubt as if it would move my 360 properly. Why even try as the sib manufacturer recommended a 20/25 HP engine.

Having the parts manual, ordered the 15 HP cover gasket which sits horizontal between the 2 piece carb assy and a wider 46 High Speed Orifice, the plug through which gasoline passes through inside carb. The idea: to force more air and gasoline intake to the engine, stripped the whole carb down, made the conversion, at ide was ok, but at full throttle trying to plane fast was dissapointing. Lost almost all of it's power.

Under trial & error, tried placing back the original 9.9 horizontal gasket and a 40 intermediate size high speed orifice, this time ok at idle, still dissapointing at wot, ended up placing the original 9.9 high speed orifice which was 36. Performed as usual.

Asked the frustrating conversion issue directly to a USA Evinrude engineer who came down here to train local Evi distributer mechanics. The conversion is: You must change the complete Leaf Plate Assy and the complete carb assy for the 15 HP model. The 15 HP plate has slight wider gas passages intakes and better chrome platted layers on leafs (reed valves) compared to the 9.9 model. The 15 carb has wider air and gas internal passages than of the 9.9. The combination of both and some minor gaskets changed around the plate assy ,will give you a final well converted engine.

Have been reading lately some tech confussions about "you have to change the complete engine manifold" in 2 strokes, 2 cylinder carburated engines, you have to change just the complete internal Leaf Plate Assy which sits in between the engine block and the manifold, being the manifold just a cover lid onto which the carb is bolted to. The same prob too about CD (Power Pack) most share the next larger HP model, 10-15/25-30. Though, will have to check that info out in the spare parts catalog of each engine brand to see if they match.

In my case, having the engine from new, perfectly well maintained and impossible to look for a new 15 decided to go for the conversion, the total cost in USA just in spare parts was $ 220 for the complete carb assy and $ 80 for the complete leaf/reed valve assy, a total astonishing $ 300 including my own hand labor which was free.

Conclussions: Don't go for this triky conversion as will cost a lot, unless you cannot find/purchase a factory new/used 15 HP, you love so much your well kept engine, or plan to fit your next lenght sib with same engine without spending so much on a new one. The converted one has a better final top speed, better hole shot and can transport more weight, mates than before, with same prop.

Bottom Line. Don't ask direct conversion issues to the factory, unless you are a direct distributer, cause will give you back answeres as: It's against the factory policy to uprate engines as a matter of owners security; other users will not know they are conducting a modified engine not stated on the engine cover and could lose boat control.

Happy Sibbing
Attached Thumbnails
Click image for larger version

Name:	Reconverted 9.9 HP.JPG
Views:	1087
Size:	104.6 KB
ID:	36814  
__________________

__________________
Locozodiac is offline   Reply With Quote
Old 09 August 2008, 12:42   #12
Member
 
Country: UK - Wales
Town: West Wales
Make: Vipermax 5.8, SR4.7
Length: 5m +
Engine: 150 Opti, F50EFi
Join Date: Sep 2005
Posts: 6,298
So you need to change the carb and reed valve on the 9.9 Jonnyrood. What year is the motor - 1996?
__________________

__________________
Downhilldai is offline   Reply With Quote
Old 10 August 2008, 11:37   #13
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
Quote:
Originally Posted by Downhilldai View Post
So you need to change the carb and reed valve on the 9.9 Jonnyrood. What year is the motor - 1996?
Yeap, need to change complete15 carb & reed valve plate assembly, not just reed valves alone, as the 15 plate has slight bigger portholes passages than of the 9.9 model. Is a 1996 RED-10/9.9 short tail model as in the posted pic. Running perfectly updated, much better than when a 9.9 model. A Bit expensive to convert though, Tohatsu engines 25 to 30 & 30 to 25 and hope other brands, converts for peanuts as compared.

Happy Sibbing
__________________
Locozodiac is offline   Reply With Quote
Old 10 August 2008, 21:57   #14
Member
 
Country: Canada
Length: 3m +
Join Date: Jul 2008
Posts: 6
Hi all,
I have done quite some extensive fiddling with the 1985-89 jonrude 9.9/15 engines.
here is a link to a posting that covers a few of you questions:
http://forums.iboats.com/showthread....ight=Snowdrggn
Due to the length I would prefer not to edit an post my entries here.

Cheers,
Snow.
PS: make sure your set up and prop are as close to perfect as possible to get the maximum benefit from your efforts. Also if you use Boyeson reeds, they idle much nicer and seem to start better, but will not tolerate a lean "sneeze", so run your idle mixture a bit on the rich side!
__________________
Snowdrggn is offline   Reply With Quote
Old 14 August 2008, 09:25   #15
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
Quote:
Originally Posted by Snowdrggn View Post
Hi all,
I have done quite some extensive fiddling with the 1985-89 jonrude 9.9/15 engines.
here is a link to a posting that covers a few of you questions:
http://forums.iboats.com/showthread....ight=Snowdrggn
Due to the length I would prefer not to edit an post my entries here.

Cheers,
Snow.
Snow,

Was reading your posts, If not mistaken, the 1996 was the last tech updated 10/15 model , that is, no other technical updates were done after next years models. Both reed valves has plate leaf & shim on top. To convert will need to replace also 2 main gaskets from plate assy, will prob break apart when removed as will be solded with use & time.

Happy Boating
__________________
Locozodiac is offline   Reply With Quote
Old 17 August 2008, 02:40   #16
Member
 
Country: Canada
Length: 3m +
Join Date: Jul 2008
Posts: 6
Loco,
The 96 year may have had the last of the tech upadates. My experience lies with the 87-89 years, which seems to have followed through to 95 as far as the exhaust tuner goes.
We try to use the 89 ignitions as they have the 7000 rpm rev limiter built in (UDL-2 ). I apologise if I mislead anyone.

Cheers,
Snow.
PS: For any given year, go on to the BRP parts site and verify what parts are different, that's what we did at the start of the project.
__________________

__________________
Snowdrggn is offline   Reply With Quote
Reply

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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 19:58.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.