carb issue help needed

trying to adjust the carbs on my 1995 BF25 3 cylinder.
Only makes any idle change with the top carb.
I can screw the air scew all the way in on the middle and bottm carb with not any change in idle. I screw in air screw on top carb and it stalls
any ideas?
I have sea foam in the tank but only have had it idle fast for 1 or so hrs .

thanks

now i found that when i choke each carb individualy the idles changes/faster. this seams to tell me the carbs are in play.

but when i pull the plug wire on middle and bottom cylinder the idle stays the same but when i pull top plug wire it stalls out.

ive moved the plugs around and the same thing happens so the plugs seam fine. the wires are fireing on all 3 cylinders.

also will not take more throttle with the choke off. idles without choke but when given more gas it stalls

when on the water i have to run choke untill getting up then when the choke is pushed off it slows down some.

seams to me like carb issue but when each carb is choked by itself it changes idle speed.

before removeing the carbs,looks somewhat difficult, i would like to be sure that is what it needs

any help/advice appreciated

Well...it's hard to believe that it is running on just one cylinder...but that is what your description sounds like. What I suspect may be happening is that it is running MOSTLY on one cylinder with the two bottoms probably firing sometimes.

With your description of what you see...plugs ok...coils firing....idle mix screws on two carbs make no difference....but the choke on each does...
...It sounds like gummed up carbys to me. I think you probably have deposits in the low speed circuits of those two carbs and that means the top one is not far behind.

Bottom line? I think they ALL need to come off and get hosed out. That is what I think.

I would also want to know...on an engine of this vintage....what the valve lash is on all cylinders. Although, I still think the carbs need cleaning.

Taking off the carbs can be difficult...but putting them back on correctly...from memory is even MORE challenging. If you attempt this yourself....you need to go VERY SLOWLY and TAKE MANY PICTURES. Having a video camera running might help too. It should be that all three can come off together as opposed to taking them off one at a time.

Cleaning them is fairly easy once they are off but you should have all the appropriate gaskets on hand before you even begin. I would also recommend replacing the three "jet-set" tubes as opposed to trying to get the old ones serviceable again. That way you should have no issues after everything is back in place.

http://www.boats.net/parts/search/Honda/Outboard Engine/0/BF25A LHSA/CARBURETOR/parts.html

In the parts link above you will want to buy all six #22 gaskets....the #38 "muffler gasket"....all three #3 "gasket set(s)"....all 3 #19 "jet-set(s)" and POSSIBLY gasket # 35 gasket, intake manifold IF you take them all off together (the easy way)

I would also recommend buying the #1 "metal anode" and replacing that while you are in there. Especially if you boat in salt water.

If buying all this stuff is "cost prohibitive" for you...it IS possible to do without new jet-sets and the muffler gasket. But if you put it all back and it doesn't run correctly...you will be left wondering if you didn't get one of the jet sets clean enough. WHICH ONE?....Well....that's why I replace them each and every time.

Hopefully someone smarter than me will help answer your questions.

jgmo your exactly rite. I decided to take the carbs down and with a utube video it was pretty easy. I did find the 2 lower carbs jet sets were clogged. so that's my problem for sure.
I cold not find the parts so the link you gave me is what I need,Thank You.

got it back together,runs a lot better. the jet sets cleaned up good so no need to replace. discovered it has an electric choke so planning on putting it on a switch,cool find. can't wait to take it out.

thanks:suzzie

That's good news! I hope your "road test" goes well. I do hope that you can also find the time to CHECK the valve adjustment at some point. If they are all ok, then that will give you "peace of mind". If they are tight though. and you get them adjusted, the engine will likely run better and you will avoid any potential breakage that tight valves can cause.

Good luck.

is checking the valves complicated to do?

thank

Not as complicated as taking the carburetors off and cleaning them! The only disassembly involved is removing the valve cover.

BUT...it is somewhat "technical" in that you must make sure that the valve being checked is completely closed and that the cylinder piston is on top dead center or TDC. Once that has been established, it is simply a matter of inserting a feeler gauge of the proper thickness between the end of the valve stem and the tip of the rocker arm that actuates that valve. So it does take a fundamental understanding of how a four stroke engine operates.

Most times, on a running engine, The VALVE STEM TO ROCKER ARM CLEARANCE will be within specification. But, on an engine that has been in service for many years and the valves have never been adjusted the "gap" between the valve stem and the rocker arm will be too tight. This is because as the engine wears, over time, the constant up and down of the valve head on it's "seat" will slowly start to deform the softer seat and the valve will tend to nestle down deeper into the seat when the valve spring brings it closed. Pretty much like looking at an overstuffed chair after it has been sat in for many years. The "sitter" sits deeper than they did when the chair was new.

This "sinking" of the valve down into it's seat will cause the valve stem to "move up" and be closer to the rocker arm. This can eventually have a negative effect in that, if the valve and rocker arm get to close to each other or actually stay in contact all the time, the valve can be opened too early or be held open....when it should be closed. This can lead to the valve face being burned during ignition and combustion or the piston actually slamming into the valve, bending it or damaging the piston crown or both.

Any owner that has a service manual and is of a mind to do their own maintenance SHOULD learn how to perform a valve adjustment CHECK. If you find the valves are "out of spec" you may choose to have a QUALIFIED mechanic do the adjustment. But again....the adjustment is fairly simple.... if not somewhat tedious

Adjusting the valves involves loosening a locking nut on the valve rocker adjustment screw and then opening or closing the screw to obtain a proper clearance as seen with the proper thickness feeler gauge.

It sounds simple but the "tedium" comes in when you tighten the lock nut and find that your adjustment has changed when you do a FINAL CHECK of the clearance. It can be aggravating. Your first adjustment will take a lot of time to get it right.

But with a little knowledge and holding your tongue "just so"....it's just more "nuts n bolts".

I took my boat out this morning and it starts and idles great. BUT it still will not take throttle. It takes a little gas and then Blaaaaaaa.

I noticed the pump ball gets rock hard but after running awile and I check it it is soft. shouldn't it stay hard? ive tried cap tight and loose for vent,same.

I didn't soak the carbs in cleaner, didn't look all that bad but shoud I do it again and soak?

any way to know that its not the fuel pump?

I will check the valves today

thanks

Yes, the bulb should stay hard.

And no, don't do anything with the carbs until you sort out why the primer is going soft. All your runability problems could be because of that.

Will it "take throttle" if you pump the primer while giving it gas?
Will it run somewhat normally with part choke applied?

The answers to those questions could indicate how you should proceed.

It sounds like you have eliminated a tank vent problem. If your hose or bulb are a few years old, it's possible there is a tiny hole somewhere that is sucking air. It can be hard to find. Sometimes it's easier to just replace the old fuel line and primer. If it's not those, check all the connections including the one at the engine quick disconnect. That wears out over time due to hamonic vibration.

The connector pin and plunger "faces" wear down and the valve can't fully open. The engine is starved for fuel as a result.

thanks for the info. when the ball is hard i don't see any leaks. I just replaced the hose and upgraded the connector at the motor but not the ball or the connector at the tank so I will do that .

the valves were good

Thanks for the help jgmo

I read a post abought pump balls and discovered mine was faceing slightly downward,fixed and gets harder,maybe fixed, but I see that the filter doesn't fill completely full. it has an air pocket. tried loosening the drain screws on the carbs and pumping it out but still will not fill completely.
Is this normal? if not what to do please.

Thanks

If you're talking about the clear "lawnmower" filter under the engine cover...it never will be completely full. That is normal.

I should have told you to check your fuel pump for leakage while you had the valve cover off. The pump can leak under the valve cover and gasoline will contaminate the oil.

If it's not leaking...it could still be a weak one. They only make about 5 to 7 psi and so most people don't have a gauge that is accurate enough to check them.

One way is to just disconnect the fuel line going to the carbs, pull the kill switch, and turn the engine over a time or two. If you get a sort of "moderate" stream of fuel then the pump is likely ok. Be careful doing this as a simple static spark could cause a fire....especially on a hot summer day!

They sell rebuild kits for the pump...I believe....so if you are unsure....that's a way to go.

You may have already solved the problem with repositioning the primer bulb. They do work better when angled slightly upward so the little check balls inside can seat and prevent siphoning back into the tank.

suzzie said:

I took my boat out this morning and it starts and idles great. BUT it still will not take throttle. It takes a little gas and then Blaaaaaaa.

I noticed the pump ball gets rock hard but after running awile and I check it it is soft. shouldn't it stay hard? ive tried cap tight and loose for vent,same.

I didn't soak the carbs in cleaner, didn't look all that bad but shoud I do it again and soak?

any way to know that its not the fuel pump?

I will check the valves today

thanks

Click to expand...

I did wind up takeing the carbs off again and soaked them in Gunk carb cleaner and all is fixed. runs like new. I will never take a carb off again and not soak.

That is GREAT news! While I'm not a big fan of soaking these plastic clad carburetors in cleaner....it seems to have worked out ok for you this time. You obviously used a solvent that isn't as "strong" as some that ate available. I only mention this because anyone reading should be aware that SOME "immersion" type cleaners are capable of melting the plastic and turning a carb into a pile of "slag"

Congratulations on getting it fixed!

jgmo said:

That is GREAT news! While I'm not a big fan of soaking these plastic clad carburetors in cleaner....it seems to have worked out ok for you this time. You obviously used a solvent that isn't as "strong" as some that ate available. I only mention this because anyone reading should be aware that SOME "immersion" type cleaners are capable of melting the plastic and turning a carb into a pile of "slag"

Congratulations on getting it fixed!

Click to expand...

Your rite, you need to take the carb all apart so no plastic is in the liquid. I used Gunk brand in a gallion can from Advance auto parts , $25.00 but can use over and over.

thanks