bf 90 carbs

hey all . I'm new to the forum and have been sitting here for nearly two hours reading through archived posts. This seems to be a great place for advice on repairs. I posted yesterday about the main nozzle removal on my bf 90. Still no replies. It probably sounds like a stupid question but i'm going to ask it again. How do you remove the main nozzles to gain access to the slow jet. Maybe mine is just so corroded that it is frozen. I considered using a easy out. there is a small thin tube that will spin but will not pull out. any help?????

Sometimes they are gooed up so bad that you may have to destroy them.

On the stubborn ones, I usually put the carb in an ultrasonic cleaner for a while to help loosen some of it up. If you do not have an ultrasonic cleaner (doesn't everyone?) use some Sea Foam or carb cleaner.

The skinny tube (jet set) is held into the upper part of the carburetor by an o ring. Generally, if you have a small screw driver, you stick it between the upper carb barrel and the little ring on the jet set. Then twist the screw driver slightly and the small tube should pop out of the top of the carb. Then, if lucky, you can use the screwdriver or maybe one a little bigger to push the small tube out, and the small tube pushes out the nozzle.

Do not use a needle nose to grab the jet set (small tube). It will most likely mess up the small holes in the tube.

This is just the beginning in getting these things clean.

Mike

Thanks for the reply. I'll try to find time to get the carbs back off today. On another note,this is the first four stroke that ive owned.i use it for recreational fishing and commercial trawling. I pull a 25 ft net. It seems to me that this thing is lacking ump on high end. I reproped,went from a 15 three blade to a 13 four blade. I expected to be thrown in the floor during acceleration.not so. Very little if any difference.this is on a 19 ft carolina skiff 198 dlx. Do you suppose it is carb related? After a good hard pull the plugs are very light tan color.seems lean to me. I dont know. Thanks again for the reply. I'll see what i can do.

Hi, welcome to the forum,

I'm not sure I would expect ANY 90 hp engine to "throw me in the floor" of a ANY 19' fiberglass boat. It would have much to do with how much gear and people load you expect it to carry. What does your transom rate at? 115? Now THAT will probably throw you! But if you are heavily loaded even the additional 25hp might be a bit of a disappointment.

I agree that the prop change should have made SOME difference but prop performance gain is something of a voodoo science if you get it right the first time every time. Most of us mortals have to "fish" around with trial and error prop swaps to hit the sweet spot.

Have you experienced a "fall off" of performance? Or, are you searching for some additional oomph? I didn't see your first post so I don't know why you are pulling your carbs to clean them. Your description of the spark plugs sounds pretty normal to me but if you are having performance problems then, yes, you could be a tad lean.

But, a lean condition is not always a fuel system issue. Have you checked the valve clearances? Verified correct valve timing? Those are two BIG horsepower thieves so be prepared to go there if you don't get much from carb service.

THANKS for the reply. I really don't know really what to expect from a four stroke. I guess that I was hoping someone would tell me some magic performance mods. maybe changing jets? I will do one thing at a time. The reason for carb cleaning is missing and coughing at idle and very sluggish transition from slow speeds to half throttle. It seems to idle great with the choke pulled 1/2-3/4 out.push it in and with the idle adjustment screw about maxed out, it will shake and eventually shut off. I bought the boat 2 years ago . it never seemed to me that it idled as smooth as it should have. previous owner said he just had carbs rebuilt. so,not knowing any better, i thought that was just the way it ran. i didn't have the coughing and spitting issues untill this spring. I have to admit that I was lazy when it came to fuel maintenance. lesson learned... thanks again for the advice. it makes me feel not so worried about trying things having a support group

Well now, THAT does sound like carb problems so you're probably on the right track. You got lucky enough to attract hondadude's attention so you will have GREAT help and, with some effort on your part, probably come out a much happier boater. I'll pitch in where I can too so,
Good luck.

Didn't have time today to pull carbs. I will keep yall up to date. Thanks again

Since you are unfamiliar with cleaning these carbs, I recommend the Honda Carb Manual....Especially for this motor. The manual has a lot of pictures and shows you, step by step, how to clear the idle passages as well as the intermediate passages (which most people miss).
It also covers vacuum balancing, which is the last thing you do, once you put all the carbs back on the motor. Balancing makes a ton of difference at idle.

I think I saw someone say that the carb manual is out of stock right now, but I would still try... http://www.helminc.com/helm/product...=&from=result&Style=helm&Sku=TM044&itemtype=N

JimmyD also found they are sold on ebay. One left http://www.ebay.com/itm/Honda-Marin...anuals_Literature&hash=item3a7e14a296&vxp=mtr

The manual is well worth the $39. A carb job, done right, with final test in water is generally around $800 - $900, depending on parts needed. I always change the jet set (skinny tubes)...they are impossible to be sure that they are clean.

You mentioned changing jets and mods.....the only reason to change jets on a Honda is when you operate the boat several thousand feet above sea level. There are normally three different jets to use. The one thing I have found with outboards, is if you try to change from the factory standards, the motor will not last as long as it should.

Once you get the motor to idle, etc properly, then you need to see what your full throttle, trimmed out, rpm is. Then you can determine if the prop is correct or not. Once you get the overall performance zeroed in, then you should consider a small pitch prop for when you are pull the net or a load. It will essentially give the outboard a little lower gear (so to speak) for the pulling. It will overrev at top end if you try to go full throttle.

In general, 3 blade props are best at top end. 4 blade props are good for heavy loads and take off...getting the back end up quickly. Changing from a 3 blade to a 4 blade with the same pitch, generally will lower top rpm by about a 50 - 100 rpm. Changing the pitch but keeping the same number of blades changes the top rpm by 150 - 200 rpm.

Before spending a lot of time on the carbs....be sure that the compression is good on all cylinders and there is spark on all cylinders. Also check the timing marks to be sure they are in alignment. You are probably right on, thinking it is the carbs, but you will kick yourself, if, after you go through the work to clean the carbs, you find that you have a bad cylinder.

Mike

I just purchased that last carb manual off ebay. Alot of good useful info here .thank you. on a totally unrelated subject, i am rebuilding a 70 hp evinrude. lost #3 piston. had block bored .030 over.bought 1 rod and a power head rebuild kit from WSM PERFORMANCE. everything looks good in the kit EXCEPT the upper rod bearings. the original bearings were a cageless design with spacers/thrust washers on ether side of needle rollers. the new brgs are a caged design with no spacers/thrust washers. it is a direct replacement for my oem #. i am concerned that they are cheap replacement junk. having little experience with marine parts. what do you think? have you ever dealt with wsm performance? am i overreacting?

Never dealt with them. Usually only deal with Flagship Marine on Evinrude rebuilds. Your questions on WSM might be better on the Evinrude forum. Honda does not sell any oversized pistons, so that type of rebuild is generally not done with a Honda.

Mike

hondadude, i have a question for you regarding cleaning the carbs. i am considering buying a ultrasonic cleaner. there are sooo many makes and models out there. do you have any recommendations.

also, i am considering doing some boat repairs on the side. i enjoy getting them to run RIGHT. i need a supplier of parts and some recommendations on where to get vacuum gauges ,digital tach, etc.

There are many ultrasonic cleaners on the market. Get one big enough to handle several carbs at once and one that is heated.. Something like this one. http://www.ultrasonicsdirect.com/ul...d=ultrasonic-cleaner-sh100-3l&channelid=FROOG

The test equipment to get will depend on what motors you are going to work on. Your basic tools will be compression gauge, spark tester, Peak Reading and Voltmeter/VOM. CDI Electronics http://www.cdielectronics.com/ sells a package of the basic test gear. They also sell software packages to analyze many different manufactures' motors (Mercury, Yamaha, Suzuki, OMC, etc) not Honda. The package is not cheap.

You can probably find a set of mechanical vacuum gauges on line (they are used by motorcycle dealers too) Something like this http://www.ebay.com/itm/Motorcycle-..._Automotive_Tools&hash=item5656b218db&vxp=mtr or if you have a lot of money and do a lot of carbs The Tec Mate http://www.tecmate.com/d_vacuummate.php It works great!

Stevens Instruments, is also a good source for test gear and tachometers. http://www.stevensinstrument.com/

Most dealers get their software directly from the manufacture that they represent....and have to pay a yearly fee for updates and support.

boats.net is as good as any for getting parts on the internet....but if you actually establish yourself as a business, with business license, tax ID, etc., you may want to establish a relationship with a local dealer to provide you with parts. If you can show that you are a business, they may give you parts discounts that are the same or near what boats.net will give you, without the shipping expense. Plus, they may have it in stock.

You are more likely to get some discount, if you provide them with the part numbers. If you are wrong on your diagonsis and have purchased the wrong part, do not expect a refund.

Also, you may get referrals from them for units that they do not work on or can not get to quick enough (if the boat owner needs something done right away).

We have several independents like that and they get a lot a referrals from us for the older outboards, Jet skis and I/O's that we do not work on.

Good luck!

Mike

thanks for the info , hate to sound so stupid, but i just purchased a ultrasonic cleaner. what solutions do you recommend. i've read about using tide,simple green, vinegar. i dont want to defeat the purpose of buying the us cleaner by destroying the carbs.???????

Wow, an Ultrasonic -cleaner is only $280!!! I would have never guessed......cheap.

here's an update, FINALLY got us cleaner from ebay. (what an ordeal) cleaned carbs and all parts. replaced slow jets with new.motor runs absolutely GREAT. just wanted to take a minute to thank everyone for YOUR expert advice.this would have been an expensive repair without the help. __THANK YOU__ David