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Need a little more power

Frank dej

New member
I have honda 8.4 BF8A sr# bzbc-1501106 Can a larger hp carb be installed to increase the hp.
If so need part number and cost of carb.
 
Horsepower is the result of several things coming together to work in "harmony" in and on the engine. The carb CAN be asked to deliver more fuel by increasing JET SIZE but the engine may not be "tuned" to take advantage of the increase and then you would be in a "RICH MIXTURE" state....wasting fuel and building carbon deposits on the pistons and valves.

Typically, when a bump in fuel delivery is done to increase power, the engine's camshaft "lift", "duration" or both is changed as well. This sometimes necessitates altered timing too. Increasing HP is usually just not as simple as bolting on a new carburetor.

But, if you wanted to try it, you can look at the parts page link below and see there are 6 different jet sizes for an 80's 8hp.

The STANDARD size is, interestingly enough, the LARGEST at 88. This is because the engines are NORMALLY sold to operate at SEA LEVEL. The carburetor can be re-jetted to compensate for altitude and, thus, the various smaller orifices are offered to adjust for about every 2,000ft. of elevation.

Interesting also, your lack of horsepower MIGHT be because you have an engine that was already re-jetted and,
possibly, the standard jet may be all you would need to give it a "kick". It may have a smaller, "optional" jet installed. The only way to find out is to take the carb apart and look.

Another thing to think about is that, over time, a main jet can "erode" and become larger. This can have your engine "over fueling" and running rich which will actually cause a LOSS of horsepower. Also, uninformed people "mucking around" with the jet could have it oversized because they tried to clean it a bit too hard. YOU MIGHT BE GETTING TOO MUCH FUEL ALREADY. Replacing a "worn" jet with the proper size could actually increase power.

Making sure the throttle linkage is adjusted for MAX carb opening is another consideration along with running a prop that optimizes the power that the engine makes.

Having the outboard properly placed on the transom with the cavitation plate near the same level as the keel is also important for experiencing the best from your outboard.


http://www.boats.net/parts/search/Honda/Outboard Engine/0/BF8AK LA/CARBURETOR/parts.html

Just some things to think about.
But, sometimes it just comes down to you need a bigger outboard to go fast.
Good luck.
 
Ditto to all the above.

One other thing to check is the timing marks. There is one on the cam that should align with the mark on the block while the "T" mark on the flywheel should align with the mark on the mount for the recoil starter. In reality, since you can not see the mark without taking off the recoil starter...as long as the "T" is in line with the cam marks, the timing should be good.

One notch off of the timing belt will allow the engine to run and idle good, but it will be lacking in power. A muddobber or similar critter nest can easily cause it to jump timing.

Mike
 
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