K&B 3.5 cc Outboard questions

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K&B 3.5 cc Outboard questions

Postby HappyOne » Fri Sep 25, 2009 9:59 am

I recently aquired an unused model #8906 and I have a few questions that I couldn't find addressed on the website.

1) What are the differences between the models, (8906, 8907, 8935 & 8950)?
2) Where can I get a glow plug wrench that fits the head of the 8906?
3) What glow plugs should/can I use? The LHS seems to only have OS ones. Is a #8 OK?
4) Is there anyone still around that does tuned pipes for these?
5) Anything special I should know about this engine?
6) How can I get some K&B stickers for my hull?

Thanks for your help
HappyOne
 
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Joined: Fri Sep 25, 2009 9:49 am
Location: Kitchener, Ontario

Re: K&B 3.5 cc Outboard questions

Postby SteveM » Fri Sep 25, 2009 12:18 pm

HappyOne wrote:I recently aquired an unused model #8906 and I have a few questions that I couldn't find addressed on the website.

1) What are the differences between the models, (8906, 8907, 8935 & 8950)?
2) Where can I get a glow plug wrench that fits the head of the 8906?
3) What glow plugs should/can I use? The LHS seems to only have OS ones. Is a #8 OK?
4) Is there anyone still around that does tuned pipes for these?
5) Anything special I should know about this engine?
6) How can I get some K&B stickers for my hull?

Thanks for your help


I'm not an expert but I did race the 3.5cc outboards for years with the Ottawa club as part of IMPBA District 1.

The original outboards had the exhaust throttle and the short skeg. Later changes went to the black carb and the longer skeg with an improved lower prop drive. There were purple carbs, red carbs (from the .45 inboard) and lastly the gold carbs over the years. The cylinder heads went from water cooled to the gold anodized air cooled version. Irwin as well as Magic Mufflers (Australian) were popular and there were a few others but can't remember the names off hand. I used McCoy MC-59 or MC-55 plugs, but you had to be sure the head button accepted long glow plugs as earlier versions used short plugs. Your local hardware store sells nut drivers and you can use one of these as a glow plug wrench. Most hobby shops have hobby specific wrenches in a pinch.

I ran Byron 25% nitro fuel and tried 40% but couldn't justify the added cost of the higher nitro fuel as the speeds weren't much different. Racers in my club found that it helped to drill a 1/16th hole in one side of the lower unit so that they could squirt some oil into the lower shaft area. This helped disperse water and keep the shaft lubed. The newer versions come with this hole drilled at the factory.
SteveM
 
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Location: Ottawa, Ontario, CANADA

Postby MECOA » Mon Sep 28, 2009 9:37 am

1) What are the differences between the models, (8906, 8907, 8935 & 8950)?

8906 had short skeg
8907 has long skeg


2) Where can I get a glow plug wrench that fits the head of the 8906?

you have to grind the OD of a 5/16 nut driver down.


3) What glow plugs should/can I use? The LHS seems to only have OS ones. Is a #8 OK?

K&B 7321 short plug for the 8906
K&B 7311 or 7300 for everything else
http://www.mecoa.com/acc/glowplug/glowplug.htm


4) Is there anyone still around that does tuned pipes for these?

Irwin made them but I don't know if he is still around.

5) Anything special I should know about this engine?

here is the owners guide
http://www.mecoa.com/kb/89/8907-og.pdf

6) How can I get some K&B stickers for my hull?
request them at
http://www.mecoa.com/email.htm
MECOA
Site Admin
 
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Joined: Mon Jun 30, 2003 9:48 pm

Postby HappyOne » Tue Sep 29, 2009 7:32 pm

Now I am starting to wonder about which version I actually have. The skeg looks pretty long to me. The serial number on the side of the engine is J0048055

Can you tell me which one it is and what year of manufacture?
HappyOne
 
Posts: 11
Joined: Fri Sep 25, 2009 9:49 am
Location: Kitchener, Ontario


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