We use a Honda long shaft 8 HP on BlewDaze. It works fine for us.
However, the Yamaha engine has a nice feature that General Boats
incorporates into tiller engine control. They use the optional
remote handle kit mount it on the tiller. It gives you both throttle
and shift control on the tiller. If we did not have a reliable
engine, we would be in the market for that one. I believe it is a
9.9 hp and GB also sets up a rudder link to the motor to pivot the
motor in parallel with the rudder. Of course, since it has a rather
large prop, it has to turn with the rudder or it will hit the
20 Aug 2000
I have the newer Honda 9.9. I checked the shop manual and I cannot
find the right screw. Any idea where to look for it? (I always
thought the throttle had a short distance of travel.)
Also I called Michigan Wheel, their advice was to use the 9.75 x 6.5
prop, when making the modification, should I use a larger one like
9.5 x 8 so I do not over-rev? It's for a 22ft. sailboat, 20 LWL,
3200# displacement and 4000# displacement loaded.
Thank you in advance for the time this will take. And I am big boy
who will not hold you responsible for the advice, looking for
Remove the hood from the motor and stand (or sit in the boat) facing
the motor. With the engine NOT running, grip the throttle with
your right hand.
As you twist it (with the motor in neutral to reduce the travel)
look for the black plastic bellcrank that is moving (it will be
very close to the front of the engine and a bit to the right (your
right) of center). Once you locate that bellcrank you will see a
yellow painted screw; that's the one!
If you move the gear shift to forward (again with the motor off)
and twist the throttle to full speed you will see where that screw
contacts the stop to limit throttle travel.
Just remove the yellow painted screw and you will have the 13.2 HP
I would use the larger prop for a 22-foot sailboat. You will over-rev
with the 6.5" prop and once you get the boat moving you will feel
like you're stuck in second gear.
The 8" prop will get your boat moving just fine and you'll have a
better cruising speed without pushing the rpm on the motor so high.
Oak Harbor, WA
The old (blue & white) Honda BF75 and BF100 were essentially the same
engine with the aforementioned changes in cam and carb. The 'new'
Honda BF9.9 and BF15 are an entirely different design. Furthermore,
the old BF100 is still made and now marketed as the BF8. Prior to
about 1988 the horsepower was designated by the FLYWHEEL horsepower,
after that, it was designated by available horsepower at the PROP;
thus the old BF100 really put about 8HP at the prop.
There is no economical or practical way I know of to hop-up the old
BF100 (at least not in the way of parts swaps). The new BF9.9
actually puts out 13.2HP (at the prop). It is limited to 9.9HP (for
legal reasons on small inland lakes requiring "less than 10HP") by a
stop screw in the throttle system. Removal of this screw gives you
13.2 HP engine with a power curve that puts the max torque a little
lower in the power band as compared to the BF15.
Various props can be used on the Hondas. There are several
available thru Honda and Michigan Prop. Size depends on what
you're trying to accomplish. The props are all the same (from a
fit standpoint) for the BF75, the BF100 and the BF8. They are
quite different for the BF9.9/15 as it uses thru-the-hub exhaust.
Les Lampman (the Honda Dealer)
I was wondering if anyone else has come across this. I was at my
Honda dealer the other day to pick up a fuel filter and plugs for
my 9.9. I was telling how much I was enjoying the motor and he said
he wanted to show me something that he said a Honda rep had shown him.
We walked over to a new 9.9 and he removed the cowl and pointed to
the throttle stop screw, which comes from the factory with yellow
paint (to show if it has been adjusted I assume). He says the screw
can be adjusted or removed to allow the throttle to open up more.
According to the Honda rep, the 9.9 would produce something like
12.6 horsepower. Supposedly, the only difference in the 9.9 and 15
is the carb jets.
Although my motor does sound like it has some more RPMs to go, I
would be reluctant to do this without knowing what the max RPM is,
if it is indeed above what is set at the factory. Any outboard is
capable of turning more RPM than the max recommended by the
manufacturer I guess, but holding up is another story.
Anyone with a 9.9 or 15 ever heard of doing this?
I don't know about the 9.9 hp but I have an 8 hp with two adjustments
on the carb. Have been curious about what they are. Does anybody know?
I can't say about your idea on the 9.9 and 15hp. Is this for the
newer block design or the older ones from the mid 80's? The bf75 to
bf100 is the same bore and stroke, the difference being the carb.
The two screws you refer to on the carb, the one at the top is your
throttle stop screw, idle in neutral should be 1200rpm +/-100, the
second screw, located just above the mounting screw is your idle
pilot screw, adjust it to obtain your highest idle, then readjust
the stop screw. Wide-open throttle adjustment is fixed.
Yes, Virginia, the 9.9 is a 15 in sheep's clothing. The only
difference between the newer Honda (97) 9.9 and the 15 is the
throttle stop screw and the two jets in the carb. The newer jets
are 52s with the old being 48s. I have done this on my 9.9 and
it is much happier now. Your local Honda dealer should be able to
order the jets for you. The two jets are @$20 for both and well
Anyone have any ideas on which is better motor? Yamaha or Honda?
Can you ask a loaded question or what? It's a bit like asking if a
Ford, Chevy or Dodge truck is better. Regardless of your personal
biases it would be hard to pick a bad truck these days.
I sell and service both Honda and Yamaha. Either is a great engine
and if maintained properly will give a whole bunch of years of service.
I don't personally like the choke system on the Yamaha as well.
It has an enrichment circuit for starting that is always "on" until an
electric coil heats a special plastic to the correct temp. If that
gizmo fails the 'choke' is always on. A bearcat to run that way, and
its internal circuits are more complex than the Honda's.
On the Honda you grab a knob, give it a pull and the choke is on;
push it and it's off. But that doesn't make the Honda 'better' or
the Yamaha 'worse', just different. The Honda has a bigger
displacement and is actually 13.2 horsepower right out of the box.
It's says 9.9 on the cowl and there is a stop screw on the throttle
bellcrank to limit rpm to the 9.9 hp level. This is to keep folks
in lakes that require less than 10 hp legal. For the rest of us
removing the stop screw (which does NOT mess with your warranty)
gives us more rpm and the aforementioned 13.2 hp.
If you're going to run the engine with remote control that's easier
done with the Yamaha (because of the choke thing) and if you want to
utilize the twist throttle remotely Yamaha makes a kit to do that.
On the Honda you have to use a regular remote control box that is
If you absolutely must have massive push then go with the Yamaha
high-thrust version. Keep in mind they get this the same way you
get pulling power in a pickup. They change the rear-end (lower
unit) gear ratio. It's like putting 4.11's in. You get more
pulling (pushing) power but you give up on the cruising/high speed
end of the stick. Unless the boat just isn't going to move without
it, stick to the standard model of the Yamaha or the Honda. Here
the Honda has the edge due to its higher displacement.
Well, that's my version ... hope it helps.
Oak Harbor, Whidbey Island, WA
Hope this provides some answers on the Honda B75, BF75, BF100, BF8,
BF9.9, & BF15.
The B75's (7.5 hp) were first, starting in 1973. They're completely
white. The BF75 (7.5 hp) was an improved version of the B75 and started
in 1978. The BF100 was introduced at the same time with bigger carb
jets and different cam for 9.9 hp. In 1987 they started rating hp
at the prop instead of the flywheel.
The BF75 was dropped (it puts out about 6 hp at the prop) and the
BF100 was given the new designation of BF8 to reflect the 8 hp it
put out at the prop. It is still available and the oldest continuous
model in Honda's line up: 1978 to present.
With the BF100 (the 9.9 of the time) becoming an 8, Honda needed a
new 9.9. That came in 1987. They engineered it as a 15 hp engine,
the BF15, and detuned it by changing the cam and carb jets. When
they did this they only got the engine down to 13.2 hp.
To keep the folks in lakes that require LESS THAN 10 hp legal and to
legally go on boats rated at 10 hp they put a stop screw in the
throttle bellcrank to limit rpm. That screw is there to protect
the consumer, not Honda. Remember it's really a 15 hp-engineered
engine. So if you remove the screw (which does NOT affect your
warranty) you get the full rpm (still a little less than the 15)
and get 13.2 hp.
So the differences between the BF100 & BF75 are carb jets and
camshaft. The differences between the BF9.9 and the BF15 are also
carb jets and camshaft. The peak torque of the 9.9 comes lower on
the power curve than that of the 15 for more pushing power at lower
rpm's. The marketing idea for the 9.9 is as main motors on sailboats
and kickers on powerboats. The 15 is marketed toward main engines on
small fiberglass and aluminum skiffs and inflatables.
Oak Harbor, Whidbey Island, WA
But seriously folks ... it's not really a boost. You're removing the
artificial limit Honda used to legalize the engine for lake use & boat
hp rating (as a dealer I can't remove the screw if the motor is on a
boat rated for 10 hp. What the owner does, I can't control). They make
sure all the dealers know about it so it can be removed for customers
that could use the extra ooomph. Even without the limit screw the 9.9
still turns less rpm than the identical 15. Besides, it helps them
sell against the Yamaha!
I'm picking up my Rhodes 22 from Stan and crew in May. I'll have
to do something about an outboard pretty soon. I'd pretty much
narrowed it down to the four-cycle Honda 8 or the four-cycle Yamaha
9.9 high thrust. I'd like to see your diatribe on starting and
maintaining a Honda.
S/V New Song
- 1) The biggest no-no is not burning the gas out of it after
each use. What I mean by this is to disconnect the fuel line and
let the motor use up all the fuel in the carburetor. The Honda sips
fuel and has very small jets in the carburetor. If you allow the
fuel to evaporate (a day or even few hot hours is enough) what is
left is the "gum" that clogs up the works. Keep two cans of old
fashioned carburetor cleaner on the boat, the one in use and the
replacement for when the first runs out. I suspect this applies to
all the small four-stokes. (also see the fuel diatribe)
- 2) The Honda 8 hp thermostat likes salt, as in salt water and
seems to surround itself with it. You have to keep yearly eye on
it (as in take it out and clean it) and try to flush with fresh water
often (easier said than done). Most people do not bother. The 8 is
hard to flush on the boat, but since a sailboat auxiliary gets fairly
low hours of use, the annual service check should be enough. Be sure
to give it a real long flush at the end of the season (the cooling
passages need it too).
- 3) Read the owner's manual, change the oil, gear lube, lube the
parts, change the plugs etc. yearly. The impeller and value
adjustment (after the first 20 hours) most likely can be done every
4 years (talk to your dealer, I do not want to go on the hook for
this), we are talking sailboat usage here.
- 4) There are 3 fuel filters on the motor, in the fuel tank, in the
fuel line before the fuel pump and at the base of the carburetor. If
in doubt change them.
- 5) My fuel sucks! It seemed like storage life changed after MTBE
was added to the gas, plus it seems that the refiners changed the mix
to add more alcohol. The problem is that alcohol likes water, the fuel
shelf life seems shorter, and the carburetor mix seems changed (i.e.
carbon in the engine). I also have a second problem with the marinas
around me having old pumps (and I am assuming old pipes and tanks) with
some crap / dirt in the fuel. I cannot say I am right about all this
or that my cure is correct but here is what I do:
- a) I use only 89 octane but avoid the higher grades because they
might contain more alcohol. If I remember correctly, the manual
- b) I installed a Rancor 2-micron filter and water separator in
the fuel line (lots of black stuff in it at year-end)
- c) I have 3 tanks on board - 2 six-gallon primaries (in use and
next up) and a 3-gallon reserve. I try not to fill them from the
same place at the same time and use them in rotation.
- d) I add a cocktail to the gas: fuel stabilizer, de-carbon and
Marvel Mystery oil, following mfr's rates and directions, I don't
want to over do it :`)
- 6) Make sure to open the tank vent! Remember to close it at day's
- 7) I keep a spare fuel line setup with priming bulb on board.
It only takes a small air leak in the fuel line to play havoc with
the engine (and makes me look silly at the motor shop, mechanic
shrugs, saying "It works fine for me.").
- 8) At the end of the year (and sometimes mid-season) I spray a
can of 'de-carbon' through the system. Works wonders!
- 9) I use synthetic oil, it's only one quart and it seems to make
starting easier, plus it makes me feel better about not changing it
during the season.
- 10) Starting the motor (8 hp) first time for the day:
- a) Set the motor height so the pull is straight back and impeller
is covered, in my case it was the plate just in the water)
- b) Gear shift in neutral!
- c) Choke about 3/4 out
- d) Turn the throttle to the maximum neutral stop.
- e) Did you open the vent?
- f) Prime it until heard no more fuel is going into the carburetor
and the bulb is firm.
- g) Pull, pull etc.
- e) If it did not catch, check the prime and c, d & e!
- h) When it starts, adjust the choke in for max rpm and adjust down the throttle to a fast idle (with practice this happens pretty fast, a cold motor turning fast is not healthy)
- i) After a minute or two, push the choke fully in and adjust the throttle to idle.
- j) Give the motor about 10 minutes to warm up before going anywhere. It will help to keep scratches off your boat and other boats. Cold motors love to stall at low speeds in gear (and they seem to know the worst times to do it).
- 11) If you are restarting the motor after the first time do
(a) and (b) from #10 and pull; depending how long the motor has
been stopped, apply the steps from 10 (you will get a feel for it
after a while), BTW remember the carburetor cleaner comment from #1.
- 12) If you are still have a problem, take the motor in.
Sometimes it is simply an adjustment to cable/linkage/settings.
Things change, cables stretch or something works lose over time
(or maybe no one adjusted it to begin with). Someone who knows
the motor and how things should be set can get it adjusted in short
Most people put Sta-Bil in their gas when they get ready to winterize.
It stops the lacquering that takes place when gas sits to long. One
thing they don't realize is that the summer heat can actually do more
damage than the winter storage. I keep the stabilizer in my tank all
year since we sail all year. I've never had a problem with the gas.
A short story about a Honda 8 hp;
Last weekend I did the season tune-up on my motor (oil, sparkplugs,
gear lube, valve adjustments, fuel filter, etc.).
The engine started fine, except it did not pee (check the water
tube). OK. I picked through the parts, replaced the impeller, no
luck. When I replaced the thermostat I found the area encased in
salt! Since everywhere else was checked, it looks like the passages
inside the engine are choked with salt. Well, the motor is in the shop
now; the guy laughed and said something about paying the rent when
I asked how much.
The moral of the story is flush the engine more than I did (kicking
I flushed my Mariner 8 with an old bucket after every run and rest
assured that I will flush my new Yamaha after every time out,
particularly in salt water usage.
17 Mar 1999
I know the Honda 8 hp motor. The difference between long and extra
long is not the standard 5 inches. From the Honda Website:
||8.0 hp Honda
||9.9 hp Honda
||(S-type): 1,010 mm/39.8 inches
||1,050 mm/41.5 inches
||(L-type): 1,160 mm/45.7 inches
||1,180 mm/46.5 inches
||(X-type): 1,240 mm/48.8 inches
||1,320 mm/52.0 inches
||(S-type): 422 mm/16.6 inches
||440 mm/17.3 inches
||(L-type): 572 mm/22.5 inches
||570 mm/22.4 inches
||(X-type): 648 mm/25.5 inches
||710 mm/28.0 inches
Just a reminder that short, long, extra long are not standardized terms. Also General Boats has changed their motor mounts over the years. The older one is the 6:1 that needs the motor tilted up. The newer one is the 8:1 that will lift the Honda long shaft out of the water without tilting, and I think gets the motor a tad deeper. I also believe a Honda 9.9 was used in the design of the new system.
- 8.0 hp Honda long shaft, mail-order: about $1600
- 9.9 hp Honda long shaft electric start, mail-order: $2400-$2500
- 9.9 hp high thrust Yamaha (four stroke), long shaft,
electric start, local dealer: $2400.
23 Nov 1998
OK, I'm basically convinced I should get the 8hp Honda.
Now, the question is where? Mike, you mentioned about $1600
mail order. Could people send me contact info? Company names,
URLs, phone numbers, etc.
I have the West Marine catalog, but they only have Nissan listed.
I thought I found a Honda site with prices listed on the web
somewhere, but now I can't seem to locate it! And I thought I
was bookmarking all the good sites. *shrug*
30 Nov 1998
Best prices I've found for Honda equipment is:
AAA Rental Center
390 Garden of the Gods Rd.
Colorado Springs, CO 80907
I know they had a website, but not sure of address. They ship
internationally, and claim to be one of the largest Honda dealers
in the U.S. We saved over $400 on a snow blower from them, and
when spot-checking o/b prices, found out I could have saved a bunch
buying from them (don't ya hate it when that happens!).