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older honda outboard help

T

troupster

New member
does anyone know the year and hp of my Honda 4 stroke motor. serial # is B100S-1503465.
was told a 10 hp. I am having problems with power, runs and idles good in trash can, but slow moving on water.
its like running on half throttle.
thanks jake
 
It is a 1983 and the model is a BF100D.

As for the running at half throttle.....there are several things we need to know to help zero in....

What size boat are you trying to push?

As you actually getting full throttle at the carburetor? You can normally tell by seeing if the lever on the top of the carburetor goes all the way to the stop on the carburetor. With the motor not running, you will have to turn the prop by hand and then shift into forward. Then advance the throttle lever to full throttle. It is limited when in neutral.

What spark plugs are you using and are they new?

Do you have good fresh fuel?

Do you have a clean fuel filter?

Does the speed pick up if you squeeze the fuel bulb?

Does the speed pick up if you pull the choke out? (starting at 1/4 then little by little go all the way out in short bursts) Holding the choke out all the way for more than a few seconds may stop the engine.

Is your tank properly vented? Check by just loosening the fill cap to allow air into the tank.

Is this motor new to you or has it run ok before?

See......lots of questions.....no answers yet.

Mike
 
hi mike and thank you
its a 14' alum. john boat. throttle seems to be working fine.
plugs are 4-5ears old, seem to both be in good shape, but I just ordered new ones to install. they are ngk dr5hs.
fresh gas with sta-bil added. engine dies when I pull choke and speed does not increase when I squeeze bulb.
it does not have a fuel filter on it, unless its internal? don't think so. I have removed carb several times and cleaned jets.
it ran great till end of last season, took it out month ago ran slow for a while then spit and sputtered and took off, ran good rest of
day. out last week ran slow the whole day. it start in 2 pulls and will idle all day.
well I hope I gave you some answers, thanks again
jake
 
"ran slow for a while then spit and sputtered and took off" likely indicates you have something getting into the fuel passages of the carb.

It clears out and the engine runs good. Then it "dirts out" again. The fact that you don't have a fuel filter could have something to do with that.

These outboards came with a small, inline fuel filter between the fuel pump and the carb. But, this old girl has been around for a while and someone probably thought she didn't need it at some point. I would plumb one back in as well as at least think about installing another in the fuel supply hose from the tank just as an added measure of "security".

They do not have to be anything fancy. Just some inexpensive. in line. fine screen filters that you can pick up at any lawn mower repair shop.

While you have the lines off, pump the bulb and squirt some of your fuel into a glass jar and let it sit for a time. Look at it closely to see if you may have any debris in it. The old metal tanks that came with these engines are all starting to break down internally and you may want to go plastic if your fuel is being contaminated by your tank.

Sorry to say it but you will probably need to clean the carb again if dirt has been the problem.

There is a chance the fuel pump is weak and perhaps pumping erratically. Unlikely but possible.

Also, another thing that would make an outboard "sputter for a while and then take off" might be;

Leaking intake assembly where, after the engine warms up, the metal expands and sort of seals up the leak automatically. This happens sometimes when a guy has been taking the carb off and putting it back again with the old gaskets when he's trying to sort out running issues. New gaskets are always advisable but we all know not always possible. Again, pretty unlikely but it could happen.

Who knows? Your new plugs might do the trick so try them first. These do run on only one cylinder and be down on power as you describe. But if that doesn't do the trick, consider some of my points.

There's some stuff to look at,
I hope you figure it out.
 
Some of the fuel lines on the older motors start to collapse internally and block the fuel flow.
So you may want to inspect carefully.

Also...try running it without the hood and see if the problem goes away. If it does, then you may have an exhaust leak of some sort.

Mike
 
well at this point in time I am trying everything,l thanks for advice I will look a them.
and it runs the same with hood off.
thanks again jake
 
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