BFP8 runs rough

My 2002 BFP8 starts like dream, idles a treat and runs sweetly enough UNTIL I put some power on, then it wants to bog (even when done gently) and for extra throttle it runs very lumpy, noisy, vibration and precious little extra power UNTIL I pull the choke open a bit and off she goes. The local Honda man thought it was resins from fuel left in the carby to evaporate that have blocked the galleries and the carby needs a strip down and clean. I left it with him for 7 weeks and it was still not done when we next needed it so I have brought it home to have a go myself. I'm reasonably handy, though a stranger to outboards. From what I've read the usual problems are with starting and idling: not the case here. Before a strip down I would like to have a fiddle with some jets if that is possible to check that those are not blocked or misadjusted. I always put clean new fuel in the tank every trip, but have not been draing the carby. I will do so in future. I have not been able to find any hints where to start with carby adjustment. Can anyone help, please? I have heard that a new carby is only $100 and that is likely a lot less than a couple of hours Australian tradey time. If I strip it down I'll need some new gaskets. Are these readily available, like maybe a service kit from Honda? Thanks in advance for advice and suggestions.

Hi Isabella

All the symptoms you describe do sound like it is running lean which means either a blocked carburettor (most likely) or a vacuum leak. I would give the carburettor a clean before adjusting anything. Here is a vid I made on doing that: https://youtu.be/ye_Ui9D8dBE

Although people will tell you not to, you can often put a carburettor back together without any new gaskets. If they are obviously damaged replace them, but otherwise don't sweat it.

Stuart

Thanks Stuart. I've had a look at your vid: excellent and clear advice, well done. I'll be having a go. Must admit I was hoping to try an adjust first but as seems straightforward enough it's probably good to give it a proper service. Good for me to learn my way around my motor.

Most carburettors don't have a way to adjust the richness of the mixture other than for idle. You can affect this by changing the height of the float sometimes, but in most outboards I have seen it is fixed and can only be corrected by replacing it.

Don't be daunted by doing a clean. Just be sure to put everything somewhere safe and even take photos as you go if your memory is anything like mine.

Stuart

I need to run it first. I brought it home without the fuel line (duh - left it on the boat) so I'm picking up a newie tomorrow. Clean the salt out. I wonder if there is any point running it in a bucket of radiator anti-corrosion stuff? The anodes look a bit furry. How do I know whether to replace them? They are quite expensive! Like most Honda "bits". Your vid is good - makes it look straightforward. Well done.

I rebuilt these little carbs professionally for about 7 years. I would suggest that you AT LEAST purchase the gasket set listed as item #1 in the parts page link below. The reason is that you may find it VERY difficult to locate suitable replacements for the small orings that go to the emulsion tube... IE: "jet-set" (item #11) and the idle mixture screw at your local hardware store. Both are very critical to the proper operation of this carb and both are likely to be damaged now (your symptoms) or, on removal. Also, it is VERY easy to damage them during install so be extra cautious when putting things back together. Use a mild lube, like WD-40, to get them to "slip in".

http://www.boats.net/parts/search/Honda/Outboard Engine/2002/BFP8D2 LHA/CARBURETOR/parts.html

Good luck.

OK point taken - I will do that. Thanks for the advice.

An update: It is fixed. Stripped the carby and during the process found that one of the mounting bolts was loose and the subsequent movement had caused the paper gasket to flog and disintegrate letting air in at the joint. During the big service we had done when we bought the boat looks like they reused the "Do Not Reuse" paper gaskets ( if they had, I'm sure I would have been charged for them) and failed to properly tension one bolt. It would have been sucking extra air, hence running sweet with extra choke. Otherwise the carby looked fine and it test ran fine once put back together Have just returned from first trip with rebuilt carby and it started first pull (nearly every time) and ran like a dream. I have rather lost faith in taking things to the Professionals, and certainly learned in this story that there is a lot that is not rocket science and any reasonably competant dummy with simple tools can do a proper job ..............sometimes
Only criticism of our motor is that it has an annoying resonant buzz in the tiller at anything higher than fast idle, can see the end of the tiller vibrating. Silenced by holding it. Any suggestions?
Thanks for the input from you people. Gave me the confidence to "have a go".

Great update! Always good to hear about a "sweet success".

I will say though that not ALL "pros" are unworthy of faith. I considered myself a bargain when I was wrenching on these daily and I know I saved most of my clients BIG $$$ many times over. Also, we have at LEAST a couple of resident pros right here on the forum that I would refer anyone to at ANY time.

But, I know how you feel. We've seen too many instances of "shysters"....passing themselves off as "HONDA TECHS" and sometimes causing more problems than they solve. All the while CHARGING for the "experience".
So...that's kinda....sorta....why....this forum is here and works so well for MOST of the people that land here looking for assistance.

ANYWAAAAAY....

As for the "buzz" or vibration....it's likely there to stay. These twins, having diametrically opposed cylinder timing and, therefore, combustion events that are as far apart as they can be....will always vibrate a bit.

I think that's why they "seem" to run so smoothly on just one cylinder when a plug fouls. The harmonics are probably close to being the same whether it's firing on one hole or both.

However, you may want to take a look at your timing marks and the condition of the belt before resigning yourself to "living with it". If the valve timing is off a tad or the ignition timing isn't spot on...you may be able to make some "adjustments" to smooth things out a bit. And, a stretched or old, dry belt is a must to replace before it jumps and leaves you flat with bent valves. We've seen some discussions lately about that very subject here on the forum.

Although....with the engine "starting right up on the first pull almost every time" and running "like a dream"... I predict that you won't find much out of order there.

Here's wishing you continued success!