Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 19-09-2008, 10:21   #16
Registered User

Join Date: Sep 2008
Posts: 2
awesome, im gonna give it a shot. Thanks for the quick responses.
__________________

__________________
dutch45 is offline   Reply With Quote
Old 19-09-2008, 11:11   #17
Registered User
 
Sunspot Baby's Avatar

Join Date: May 2003
Location: New Bern, NC
Boat: Prout Manta 38' Catamaran - Sunspot Baby
Posts: 1,521
Images: 14
I went to a bigger dinghy (my old one was stolen) so I needed more power. It definitely made a difference. With our Advanced Inflatable 11' catamaran dinghy we do 15 kts with the two of us (about 375 lbs total) in perfect conditions. Can't plane with 4 adults.

George
__________________

__________________
She took my address and my name
Put my credit to shame
Sunspot Baby, sure had a real good time
Bob Seger
Sunspot Baby is offline   Reply With Quote
Old 19-09-2008, 15:01   #18
Senior Cruiser
 
Roy M's Avatar

Cruisers Forum Supporter

Join Date: Feb 2007
Location: Southwestern Yacht Club, San Diego, CA
Boat: Searunner 40 trimaran, WILDERNESS
Posts: 3,041
Images: 4
Chuck, I was being cute about the decal.
__________________
Roy M is offline   Reply With Quote
Old 21-09-2008, 00:08   #19
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
We also have 9.9 HP outboards in NZ that are mainly produced for the Ozy market. In Oz, you have to have a licence or registration or something like that for 10Hp and up. So hence 9.9Hp.
There is not a lot of point in making a dedicated 9.9Hp when there are already 8Hp motors. It's also the reason why the weight difference between 8Hp and 9.9's are such a big step.
Reject or replace the carb and away you go with a 15Hp.
One could ask why the price should be different between the 9.9 and 15 though. Surely they should be the same.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 26-04-2009, 09:56   #20
Registered User

Join Date: Apr 2009
Posts: 3
hey sorry for bringing up an old thread but i have a 1988 merc 9.9 and i've heard to convert it to a 15 you need a carb, possibly intake manifold and exhaust tube/manifold can anyone confirm this for me
__________________
wpg_snowboarder is offline   Reply With Quote
Old 26-04-2009, 10:21   #21
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Quote:
Originally Posted by Sunspot Baby View Post
Sonny:

The reason I pursued this was that in another life I had an Evenrude 9.9 that could be converted to 15 simply by changing carbs. A prop with more pitch took advantage of the 50% increase in power. I lived on a private lake with an HP limit of 10. Being able to make a stealth 15 out of my 9.9 was a very appealing option. Driving a 16' pontoon boat that extra 5 hp made a big difference. Still the little john boats with 8 hp ran off and left me.

George
Given the cost of outboard parts, would it have been cheaper to buy a 9.9 engine cover and put it on your 15? I would imagine its exactly the same size. I went and priced out the difference...its only $145. I cant imagine getting those parts for less than that.

As far as the original question goes, I would be more inclined to sell the 9.9 and buy a used 15. The difference for two new engines is only $145. I bet the parts are going to cost more than that. Your time to do the conversion is also worth something as well.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 26-04-2009, 10:41   #22
Registered User

Join Date: Apr 2009
Posts: 3
trying to find a good used 15hp shortshaft im my city is almost imposible and theyre quite a bit more than 9.9s i got a minty looking fresh rebuilt 9.9 from a small engine mechanic down the street from me for a good price. he's done the conversion on omc motors and its just the carb but he's not sure about the merc. i can get used parts for almost nothing and being a millwright i love tearing stuff apart and workin on it so doing the work on the motor is no problem
__________________
wpg_snowboarder is offline   Reply With Quote
Old 26-04-2009, 11:02   #23
Registered User
 
Celestialsailor's Avatar

Join Date: Nov 2006
Location: In Mexico, working on the boat
Boat: Hallberg Rassy 35. and 14ft.Whitehall pulling skiff.
Posts: 8,013
Images: 5
Quote:
Originally Posted by David M View Post
Given the cost of outboard parts, would it have been cheaper to buy a 9.9 engine cover and put it on your 15? I would imagine its exactly the same size. I went and priced out the difference...its only $145. I cant imagine getting those parts for less than that.

As far as the original question goes, I would be more inclined to sell the 9.9 and buy a used 15. The difference for two new engines is only $145. I bet the parts are going to cost more than that. Your time to do the conversion is also worth something as well.
This is quite true and if you buy a 15, it should be a 4 stroke especially if you are on a lake. The pollution of a 2 stroke is devastating to the fresh water environment. I would imagine one of the reasons to limit hp to 10 is for pollution reasons as well as speed.
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"

http://wwwjolielle.blogspot.com/
Celestialsailor is offline   Reply With Quote
Old 26-04-2009, 21:39   #24
Registered User

Join Date: Apr 2009
Posts: 3
im not going on any lakes that have horsepower limits on them so im not worried about it making look like a 10hp i would love to run a 4stroke motor but my little boat wont handle the weight, my 4hp 4stroke kicker on the big boat weightes the same as my 9.9 so i 4stroke would weigh way to much to make the boat safe
__________________
wpg_snowboarder is offline   Reply With Quote
Old 23-04-2010, 09:54   #25
Registered User

Join Date: Apr 2010
Posts: 1
Yes you can do it. I have a 92 merc 9.9 that has been half way converted. the carb has been changed but i need to change the exhaust tube (which I am having a hard time finding because of the age) the carb is around 200 but the tube is cheap, like 30 bucks or so. on mine the 9.9 tube is 1/8 of an inch smaller than the 15. converting makes a big difference. for us folks with little boats 4 strokes are not an option they are just too heavy.


If anyone has any tips on where to find that part i would appreciate it. the part # is 41344a-3
__________________
flipit is offline   Reply With Quote
Old 24-04-2010, 17:12   #26
Registered User
 
Sunspot Baby's Avatar

Join Date: May 2003
Location: New Bern, NC
Boat: Prout Manta 38' Catamaran - Sunspot Baby
Posts: 1,521
Images: 14
Just to restate the original need. I had a dink with a max HP rating of 10. I bougth a 9.9. Went with 2 stroke for the weight advantage.

That dink was stolen. The new one was rated at 25 HP max, but I didn't want to pay the $$ for a new engine and felt that if I could bump my 9.9 to 15 it would be money well spent.

I bought a new carb and gained significant HP increase. Money well spent.

Local parts guy researched part numbers of both engines and found no difference on exhaust side and/or ECM. Carb only.

Still running that little hummer and happy as heck.
__________________
She took my address and my name
Put my credit to shame
Sunspot Baby, sure had a real good time
Bob Seger
Sunspot Baby is offline   Reply With Quote
Old 27-05-2010, 08:06   #27
Registered User

Join Date: May 2010
Posts: 4
Quote:
Originally Posted by Sunspot Baby View Post
I bought a new carb and gained significant HP increase. Money well spent.

Local parts guy researched part numbers of both engines and found no difference on exhaust side and/or ECM. Carb only.
I have the same motor and was hoping that I could just replace the jets and get the same result. I may be oversimplifying: more fuel = more power?
__________________
elmcken is offline   Reply With Quote
Old 27-05-2010, 09:45   #28
Registered User
 
Sunspot Baby's Avatar

Join Date: May 2003
Location: New Bern, NC
Boat: Prout Manta 38' Catamaran - Sunspot Baby
Posts: 1,521
Images: 14
The part number on the carbs are different. It could be only the jets, but it could be venturi or throat diameter which I suspect. You need more air, not just more fuel in the air you have.

George
__________________
She took my address and my name
Put my credit to shame
Sunspot Baby, sure had a real good time
Bob Seger
Sunspot Baby is offline   Reply With Quote
Old 06-07-2010, 14:08   #29
Registered User

Join Date: May 2010
Posts: 4
Quote:
Originally Posted by Roy M View Post
My assigned motor was a Mercury 9.9. The difference is the jet in the carburetor. All the other goodies are the same engine.
Sorry to reply to an old thread, but I was wondering if you think I could just change the jets in my 2002 Mercury 9.9 2-stroke carb to get more power. I posed the same question in another thread and Sunspot Baby thought the carb itself might be different allowing for more air intake.
__________________
elmcken is offline   Reply With Quote
Old 15-10-2010, 17:56   #30
Registered User

Join Date: Oct 2010
Posts: 1
I'm looking at doing the same thing to my 9.9 but was told it woudn't give any more power. Also it would seem to me that a new prop would be in order. Where did you find the Merc parts diagram?
__________________

__________________
kddunn is offline   Reply With Quote
Reply

Tags
2 stroke

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
OMC 2-Cylinder 15hp 2-Stroke Sail Drive Engine Van Engines and Propulsion Systems 7 17-04-2010 07:19
Shear Pin in 2-Stroke 15hp Yamaha Outboard... beachgirl1952 Propellers & Drive Systems 3 18-01-2010 16:35
2 stroke vs 4 stroke? Shaft length? Piper'sGirl Engines and Propulsion Systems 6 06-06-2008 15:08
4-Stroke vs. 2-Stroke Outboards The_PIRATE Engines and Propulsion Systems 17 05-10-2007 05:37
Yanah 15HP vs. Tohatsu 18HP (2-Stroke OB) The_PIRATE Engines and Propulsion Systems 2 28-08-2007 13:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:13.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.