Honda BF 8 conversion to 10 hp

[Emery]

I have a 2005 BF8 outboard on my 14 ft. aluminum boat. Runs great and always starts.

I've looked at the specs of both the bf 8 and bf10 and I've noticed the following:

both motors have 222cc displacement, and all other specs are also exactly the same. Only thing that's different is the bf8 producing 8hp@5000 RPM and the bf10 producing 10hp@5500 RPM.

I've heard and read about the possibility of converting my 8hp into a 10hp by removing a restrictor plate inside the carb?

I guess I would like the extra power of having a 10hp if that's possible.

Does anybody know more about this and if it's a good idea or not?

Many thanks from Holland!

Emery.

 

[lexi]

Re: Honda BF 8 restrictor plate

Re: Honda BF 8 restrictor plate

Don`t know anything about the new engines. 25 per cent power increase for 500 revs sounds like a lot so check it out thoroughly to make sure that power is available by simply opening the carb. Of course if you look at it the other way it could be like engine is really a 10 but detuned to an 8.

Alex

 

[Emery]

Re: Honda BF 8 conversion to 10 hp

Thanks for your reply, lexi. I think the 8hp is just a detuned 10hp like you said.

Here's the specs about the 8 hp:

ENGINE
Type 4-Stroke OHC Twin Cylinders
Displacement 222cc (13.5 cubic ins.)
Bore & Stroke 58 x 42 mm (2.30 x 1.65 inches)
Full Throttle RPM Range 4500-5500 RPM
HP Rating @ Propshaft 8HP @ 5000 RPM
Induction Scavenging SOHC
Valves per Cylinder 2
Fuel Delivery Single Venturi
Ignition System Programmed Ignition System
Starting System Manual/Electric
Lubrication Wet SumpWater Cooled
Cooling System Electric 12 Amps (148 watts)
Alternator Manual 6 Amps (76 watts)
Trim Range 5 Stage 4?-8?-12?-16?-20?
Tilt Range 71?

DRIVE
Gear Ratio 2.33:1 (12/28)
Gear Shift F-N-R
Propeller BF 4 Blade Aluminum (S/L) 9 1?4 x 8 inches
Propeller BFP 4 Blade Aluminum 10 x 6 1/2 inches

And here the specs of the 10hp:
ENGINE
Type 4-Stroke OHC Twin Cylinders
Displacement 222 cc (13.5 cubic inches)
Bore & Stroke 58 x 42 mm (2.30 x 1.65 inches)
Full Throttle RPM Range 5000-6000 RPM
HP Rating @ Propshaft 9.9HP @ 5500 RPM
Induction Scavenging SOHC
Valves per Cylinder 2
Fuel Delivery Single Venturi
Ignition System Programmed Ignition System
Starting System Manual/Electric
Lubrication Wet Sump
Cooling System Water Cooled
Alternator Electric 12 Amps (148 Watts) Manual 6 Amps (76 Watts)
Trim Range 5 Stage 4?-8?-12?-16?-20?
Tilt Range 72?

DRIVE
Gear Ratio 2.33:1 (12/28)
Gear Shift F-N-R
Propeller BF 4 Blade Aluminum 9 1/4 x 8 inches
Propeller BFP 4 Blade Aluminum 10 x 6 1/2 inches

As you can see everything is exactly the same except for the HP rating@RPM.

My guess is that they put a restrictor of some sort in the carburator to downsize the 10 to an 8hp so that they can use the same block wich would be cheaper for them to manufacture instead of a completely different block.

anyone else got more info/ideas before I examine the carb?

 

[Emery]

Re: Honda BF 8 conversion to 10 hp

bumpity

anyone else have more information/suggestions?

 

[wake_rider]

Re: Honda BF 8 conversion to 10 hp

bump

Anyone?