Logo
FULL SITE MENU

Honcda 9.9 4 Stroke

B

brotus

New member
My 9.9 will start fine. Idle up and down fine for a about 2 minutes then it drops to a very low idle and then quites. I've taken off the carb and thorouly cleaned it. To me it seems like a thermostate problem, if thats even possible. The engine did take a hard knock to the lower end but is still pushing out water very well. Any help would be greatly appriciated.
 
Since you make no mention of "futzing" with the choke, I'm assuming it is a 9.9D and has a bystart (electric choke) enrichment system. Doesn't matter much if it does or doesn't, I just throw that out for discussion.

It's the carb. When you cleaned it, did you:

Remove the idle mixture screw and clean the low speed passage and replace the oring?

Remove the float chamber and clear the "tunnels" in the bowl?

Remove the intermediate and low speed emulsion tubes (jet set) and clean them replacing the oring for the small tube?

Clear the accelerator pump passage, making sure that the delivery tube will eject a 6' (six foot) stream out the back of the carb throat with the throttle plate propped open?

If the answer to ANY ONE of these questions is no, then you have more work to do.

Not trying to be a smart @$$ but these carbs are a bit finicky and that, no less, is what it takes to get the outboard to "purr" when the carb gets a bit of dirt and scale built up inside.

I just walked a guy through his 9.9 and he had it on and off three or four times even with me tutoring him because he THOUGHT he had done enough and got it clean. When he finally did get it right, he was one happy systems analyst and I was really glad not to have to keep typing anymore.

The Honda carb manual is $39.95 from Helm Inc. if you really want to do it right. Find it here;
http://www.helminc.com/helm/Result....r=&Category=&Keyword=&Module=&selected_media=

I'll be happy to walk you through the procedures if you want.
 
Yes. PLEASE. Half the stuff you mentioned I don't even know what they are. Also I bathed the carb in carb cleaner for 24 hrs and there was still varnish on the bottom of the bowl. Do you have any suggestions on what might work better. Thanks
 
That can be a problem, not knowing what or how these things work. Understanding how they work is key in getting them clean again. If you don't want to purchase the Honda carb manual, then be prepared to be confused over the next several days. Before I started with you, I would urge you to commit to buying at least a rudimentary list of replacement components. Trying to clean a carb and then reassembling it with defective, used seals is folly.

I have some questions that we need to get out of the way. Do you know if yours is a 9.9A or 9.9D or, is it a pre 2001 or 2001 and later model?

Do you have a manual choke or an "auto choke". The electric start motors have auto choke.

And, what type of "carb cleaner" did you bathe the carb in? There are some harsh cleaners that cannot be used on these carburetors. If you just soaked the bowl, you would be ok but if you put the main body in the wrong solution, we might already be "done". Not the end of the world by any stretch but just the end of this particular carb. I will explain after I get your response.

Get back to me a.s.a.p. with all that and I can shoot you a prospective parts list and "options".
 
Well, that stuff looks like it is pretty mild so I don't think that's an issue.

I'm going to ask you one more thing. On the side of your carb that faces outboard, there is a little rubber boot or bellows looking thing with a stainless steel pin coming out of the top of it. The pin goes up and into a little black plastic "ball" socket that is part of a linkage "arm" connected to the throttle plate shaft.

OK, here's the question: When you operate the throttle and the cable pulls the throttle open does the black plastic linkage push the pin and bellows down? And, when you release the throttle, does the pin, bellows and black plastic "arm" go back up? Or, does the arm, pin and bellows just remain where they are? Get back to me when you can about that.

Here is the list along with a link to the page you can order them from. It's about the cheapest place to get Honda parts.

Item #1 in the link...gasket set...$9.12...buy one

Item # 4..screw set, idle mixture $6.34...buy one

Item # 19.......gasket, mounting $2.21...buy two

I usually recommend that anyone doing this for the first time replace item # 15, jet set...$20.13. But, if money is tight, it can be reused. THAT IS, IF YOU CAN GET IT SURGICALLY CLEAN AND IF IT DOES NOT HAVE A SMALL CRACK IN THE TUBE AS THEY SOMETIMES DO. Personally, I replace them every time because they've given me so much trouble over the years. Let your pocketbook be your guide.

And, if that little black boot or "bellows" is torn in any way, it is mandatory that you replace it.
That is Item # 11, cap...$7.23 If it is not torn, you must NOT tear it when working on the carb.

Here's the link:
http://www.boats.net/parts/search/H.../BF9.9DK0 LHA /CARBURETOR (MANUAL)/parts.html

You may notice that this page is for a 2007. The reason is, the carbs are the same for 2001 on up and the parts page for your year has some typos on it that I thought would confuse you. Use this page and you'll be ok.

Other than that, you will need AT LEAST one large can of WD-40 and Two or Three cans of spray carb cleaner or brake kleen. Sometimes you can buy brake kleen cheaper and it works just as well. I leave that up to you.

If you can find some multi stranded automotive electrical wire that you can take the insulation off of and separate the wires, that makes a good tool for cleaning out some of the passages in the float chamber. If you have an air compressor and a SAFETY tipped blow gun, that helps too. A good #0 phillips head screwdriver a #1 phillips, A small pocket, slot screwdriver and a soldering iron will also make the job go smoother. I use dental picks alot for manipulating things and careful cleaning. But, if you don't have any, you can make do with something else.
 
Parts are all ordered. Even the jet set. Figured might as well save myself the headaches. Is there anything I can start before they get here?
 
Ok, that's a good start. Yes, we can do plenty to get ready for the new parts.

Please get used to me asking you questions and then, please, respond. I will be asking you many during the process and your response will pretty much dictate how we get on.

There is an outstanding question at present. It is about how the accelerator circuit and linkage responds upon throttle application and decel. I need your feedback to decide what to emphasize.

Here is another question: In your opening statement you said; "My 9.9 will start fine. Idle up and down fine for a about 2 minutes then it drops to a very low idle and then quites."

Starts fine with the choke pulled? No choke? Idles up and down? Do you mean you are doing something with the throttle or the choke or is it "up and down" on it's own? Please give ma a little more detail about that.

Also, do you have the soldering iron?

Ever use a two way radio? OVER.
 
Hi sorry for the slow replies. Here are the answers to your questions.

1.) Concerning the throttle application and decel. It seems to work fine. freely and smooth up and down.

2.)No choke needed for starting. With in 30 seconds I can turn the throttle wide open and run it like that till it drops to a low idle and stops or I can start the motor and keep it at a low idle and around the same amount of time it drops to a low idle and stops. The motor doesn't surge at all during the tests. It start on the first pull, no choke, stays at what ever speed I set it at and then drops to a low idle and stops.

3.) Yes I have a soldering iron

** hope you don't mind the 123 for the questions. I just find it easier


Thanks again for the help
 
Don't worry about being slow. I'm slow too. As a matter of fact, I'm leaving town today and probably won't respond again after this until tomorrow. The 123 format is just fine. Anything will work as long as we're communicating. Sorry to say I wish I had this info prior to giving you a parts list since this sounds more like a fuel supply problem than a carb problem.

So, here come some more questions.
After it shuts off as you say above, how long is it before it restarts? Do you do anything special to get it to restart?
Have you replaced any fuel line items such as the tank, the hose, the primer bulb or the hose to engine connector?
 
I got your message in time and stopped the parts order.

I can start it again in a matter of seconds. I haven't replaced any fuel line items. I do have a brand new fuel line and might try that tonight and see what happens. It would be VERY nice if that was the problem. fingers are crost.
 
ok. Did a bunch of tests on the motor. Tried the new fuel line and got the same results
as before. But, on the new line the bulb wouldn't stay completely hard. So I tried pumping
the bulb continuesly and the engine lasted a little longer. Tried starting again as soon as
the engine died. It would last 20 to 30 seconds. Did this afew times. same results. Then I
let the engine sit for 1 minute and restarted. This time the engine lasted much much longer.
I hope this info helps in finding the problem.
 
That's great! I was feeling a little bad that I might have unnecessarily had you spend money. Definitely jumped the gun on this one. I just figured that if you were already taking the carb off and cleaning it you had covered this ground already. My mistake.

Anyway, this "symptom" sounds just like a fuel line that might be sucking air through a pinhole or a tank vent that is not open or that is clogged. You didn't say what, if anything you did to get the engine started, like squeezing the primer bulb because it goes soft. That sort of thing. Check those things out and we'll see where you stand.
 
I tried the primer bulb but couldn't get it to completely go hard. Also tried continously pumping the bulb while the engine was running. This made it last a little longer. The best result was to let it sit for 1 minute and then restart. This made it run twice as long. I did try the engine with the cap of the tank so there wouldn't be a problem with tank. Could it be the hose conections on the ends?
 
Hmmm. Interesting. The bulb should get hard. If we figure out why it's not, then that will probably be the fix. First thing is... are there any leaks under the hood? Make real sure there are no leaks anywhere when pumping the bulb. If not, you could just have a bad check valve in the primer bulb. It would be crazy if it were that simple and we've done all this typing :).

One thing that always worries me about the fuel pump on these is that it could leak and dilute the oil. I've only seen one in 6 years that did that but it's something to keep in mind. I'm hoping it's the bulb. They usually only last three or four seasons so if yours isn't new and you don't see any leaks, get a new one and try it.

Anybody else out there watching got any ideas here? All suggestions appreciated.
 
Did some more tests. I bypassed all fuel connections up to the fuel pump intake. The primer bulb stayed hard through all tests but I got the same results as before. Even tried pumping the bulb more during the tests. Same result. Did notice the oil level was higher then the full mark, but oil looked like new on the stick.
 
I'm confused now. You say the bulb stays hard now and it wasn't getting hard before but you still have the same symptoms?

How long have you had this outboard? Did it always start without pulling out the choke?

I guess what I'm asking is... if you've had this motor for a while, what has changed from the way it used to be when it ran ok? Lets sort of start over from the beginning and see if we can't get a baseline.
 
I Think I may have forgotten to mention that I switched back to the original fuel line and primer bulb. On the other primer bulb it seemed like the primer bulb was made of really soft rubber and that it just seemed to never get hard( if that makes any sense). The engine does need the choke on for the first startup but after the first no choke needed. I've owned the motor for 4 years never really had a problem with it other then the impeller needing to be changed. Im going to try another test I heard about to see if the fuel pump is working correctly. Aslo I went over the engine and can't find a leaking hose anywhere.
 
Did you check the crankcase vent hose to make sure it is not plugged with debris?

One test of the fuel pump is to connect the line from the fuel bulb directly to the carburetor and have someone continually squeeze the fuel bulb (gently) to act as the fuel pump to keep the carb bowl full. Plug the hose from the fuel pump with a bolt to keep fuel left in the system from shooting all over. If the motor runs good, then it is either fuel pump, fuel chamber (if it has one), fuel filter, or something in the fuel line on the motor collapsing.

If that does not identify the issue, crack the cap on your fuel tank to assure that the tank vent is not plugged in that either.

One other test for the carb, would be to pull the choke back out some, when the engine is dying, to see if it picks up. If that helps the problem, then the carb still has issues. The choke, actually, allows more fuel to flow through the carb.

Mike
 
Ok, we're moving in the right direction. Yes, check to make sure the pump is pumping. It should make around 2 1/2 to 3 psi pressure. That means when the line to the carb is disconnected and put in a container, while cranking the engine over, there should be a SMALL stream or "gurburble" of fuel coming out. Doesn't take much at all to keep these babies fed. Use the kill switch while doing this to avoid accidents and fire. If that checks out, I think we're back to tearing down the carb and proceeding with a good clean out.
 
Did some more tests on the engine. I started by disconnecting the line from the fuel pump to the carb. Lots of fuel came out of the hose. Just wish I had a pump tester. I also removed the extra oil from the engine and brought it down to the full line. Here's the strange thing. The motor ran three times longer than it did before. But gave the same results as before, once it warmed up. It is a really cold day here, about five degreases. Is there a chance this could be a temp sensor gone bad. The way it reacts just seems so mechanical. When it drops to a low idle it doesn't miss at all or hick up and die. Just a thought. Are there any sensors even in it that could make that happen?
 
Yep! You might be overheating, thermostat stuck closed or the temp sensor is bad.

If you see water flowing out of the telltail, most likely your impeller is ok.

In your first post, you thought it might be a thermostat issue. Did you ever check it? Just remove it, replace the cover, and run the engine and see what happens. You should not run the engine on an ongoing basis without a thermostat but for testing purposes, it is ok. The idle may not be smooth, but it the motor keeps running, you should replace the thermostat.

The temperature sensor is located just to the right of the thermostat. It's resistance varies with temperature. About 5000 ohm at freezing and near zero ohms over 250 deg F. I am not sure if the motor runs if you pull the connector off...never tried it.

The above may be a wild goose chase, but it will not cost anything but time.

Mike
 
o.k. we might have something here. I pulled the thermostat and what a mess. The thing is all rusted and coroded. Did the boil test on it and no movement what so ever. Orded new thermostat and o-ring. My question is, is there a way to clean all the garbage out of the motor before installing the new thermostat. Other then just regular flushing.
 
It looks like persistence wins out. A thermostat stuck closed will cause that motor to shut down.

As for the flushing.... is it salt build up? Normal junk from fresh water?

Many on the forum suggest Salt a Way. Never used it...being in a fresh water area.

When Jimmy gets back, he will surely have an opinion...or someone else will chime in.

Mike
 
I have no opinion about Salt Away. I've heard good and I've heard bad. I have never personally used the stuff.

Get what you can, as deep as you can with mechanical means. Scraping, chipping. blowing out.

BUT! Scale will actually embed in the metal and if you get too aggressive, you can start chinking out pieces of the engine. The worst part is what you can't see and can't get to. It's in the head and the block. Sooooo....

After that, I would try this; CAUTION...THIS IS EXPERIMENTAL...DO SO AT YOUR OWN ...whatever. You get the picture.

Prestone makes two products for cars that are HIGHLY effective. One is...COOLING SYSTEM FLUSH and the other is...COOLING SYSTEM CLEANER. Problem is, they're made for cars. Oh, I already said that.

Since the stuff is for cars, they designed them to be used with systems that contain 1.5 to 2.5 gallons of water. I have a unique can I can put the lower end of an outboard in and fill up to the water intakes. But, even though it's a tight fit and skinny, it still takes around 5 to 6 gallons to cover the intakes. So, the "recipe" has to be doubled. The good part is, these products aren't all that expensive.

You use the COOLING SYSTEM FLUSH first. Just follow the directions but use enough to treat the amount of water you have in your tank or you will just be peeing in the breeze. FLUSH and rinse with the T Stat removed.

Then, use the COOLING SYSTEM CLEANER. This stuff is powerful and breaks down scale off of the metal. Same precautions as with the flush then rinse thoroughly. THOROUGHLY!

When you open up the housing to reinstall the stat, it should be sparkly clean. Note that I say "should be". Why do I say "should be" you ask?

It's because I've never done this. See warning above. I intend to do this but I have NEVER ACTUALLY DONE IT YET!

Soooooooo,...I don't know...well there are many things I don't know. As you have probably already figured out by typing with me for days and days.

Anyway, What I don't know about this is what this stuff will do to a rubberized water pump impeller. I have used this stuff to clean AUTOMOBILE radiators and cooling systems for years and it works GREAT on those. Turning old, scaly, clogged radiators to shiny and gleaming clean, almost new looking inside.

But, what it will do to the impeller or, more importantly, what it might do to the seal in the power head where water enters the block from the water tube, I just don't know.

I had intended on doing some "trials" on this stuff and how it affects rubber components but I never got around to it what with meeting all the new friends I have now since I got old. Mostly MDs.

So, you're on your own there but I thought I'd throw it out there in case you might want to be the guinea pig. It would save me a whole bunch of time and effort. And, if you won't do it for me, what about mankind?:)

Alright, SO WHO"S NEXT HERE!
 
Big Thanks!!! to jgmo and hondadude for all the help. Changed the thermostat and ran it for a half hour. Just like a new motor again.
 
Good deal! Thanks for the feedback.

Wish there was some way to highlight and showcase all of Jimmy's explanation on how to clean the carburetor though. There is a lot of excellent info in his posts. His finger tips must be pretty worn down.

Mike
 
Well, on this one, I can say I kept brotus busy until Mike came up with the solution. So, I take full credit!
Seriously though brotus, good onya for hangin' in there and gettin" the dang thing runnin' again. I'll remember this one and maybe be a little more cautious about ripping a carb off a guy's engine...but probably not:)
 
Back
Top