BF8 High Altitude Jet

[drstressor]

I have a 1998 Honda BF8 engine and I used to routinely swap out the carburetor jets when I moved the boat from sea level to 6000+ feet. I have somehow lost track of which jet is currently in the engine. One has "88" stamped on it and the other has no marking at all. I would think that the unmarked jet is the stock (low altitude) jet and the one marked "88" is for high altitude.

Does anyone know if that is indeed correct?

 

[sbbloom69]

Re: BF8 High Altitude Jet

I'm in the same boat with my BF75 (7.5hp). My main jet is the 88, so I think that is the sea level main jet.

The Keihin carb site lists the range for the BC carb as 72 to 88. So, I'm going to order an 84 and a 80, try each and go with the one that works the best. I sail in New Mexico (5800 to 6800 feet).

Stu
Los Alamos

 

[eipeldau]

Re: BF8 High Altitude Jet

Stu,
Could you please post Keihin's website address, from which you found info about your carb? I have a BF20D motor and would like to have that source of info too.
Thank you!

Henrique

 

[sbbloom69]

Re: BF8 High Altitude Jet

Hi,
Try this link.

http://www.keihin-us.com/am/tuning/

Look for the link for the "jets list.pdf". Open the pdf, and they show all the various jets for keihin carbs.

The #88 out of my BC carb out of my BF75 Honda matched the "8.5mm" jet from the column labeled 99101-124. Its not a sure thing, but the #88 jet looks like that column, and their is a #88 in that columns list. The list doesn't cover the BC carb (probably too old).

I did find an #84 and a #82 on the parts list at

http://www.boats.net/parts/search/Honda/Outboard Engine/parts.html

I hope its OK to post a link to a competitor site. Go to the "pre-1997" list, and drill down through the Model and serial number links. You will get to the Carb list with exploded parts diagram. In there were the listings for the stock #88, and some smaller ones that were "in stock". I ordered the #84 and #82 for testing.

Stu

 

[eipeldau]

Re: BF8 High Altitude Jet

Thank you very much, Stu!
Right now I'm not in need, but I always like to have all the possible info sources in hand.
Thanks again!
Henrique

 

[MechBRR]

Re: BF8 High Altitude Jet

This is good info as I'm planning to do some lake boating at higher elevation, but I'm still confused on the sizing? Would the larger number jet #88 be used at higher elevation, or would the lower numbers (#72, #78) work better at elevation? Should I adjust the air needle as well?

Thanks