problem with honda 90

i have a pontoon with a honda 90 hp. i rebuilt the carbs last spring and it ran fine last summer, but this spring i noticed it would not start unless i set throttle about half way and when i tried to throttle down to idle it would die. the other day i was messing with it and raised the motor trim up to about 45 degree angle to work on it, for some reason i started it and it idle great, but when i started lower the trim back down it shut off and would not start back at idle until i raised the trim back up. i am miffed on this and any help would be appreciated, i dont know if there is a sensor or what is causing this problem. thanks for any help

There are no sensors on the 90 that vary by tilt angle except for the trim and tilt sensor. It only sends signals to the trim meter.

This is an interesting problem...here is a real wild a-- guess...

It is possible that one or more of your float valves are stuck and one or more of your carbs are flooding. As they flood, the engine runs poorly. That may also be why you have to advance the throttle so far to start it.

Now here is the stretch.... as you are tilting up your motor, the excess fuel may be coming out the front of the carb/carbs instead of being sucked into the intake. There may be a point where gravity is "metering" your fuel just right and allowing the motor to run ok.

Take off your hood and squeeze your fuel bulb and watch around the carbs for any fuel. If my "wag" is correct, you will see evidence of fuel coming out of the carbs.

If this is not the answer, then I hope I put a smile on someone's face today...

Mike

First let me say that I have only experienced this "phenomenon" with a fleet of 20 hp Hondas with trim tilt and have never worked on a 90. But, what you describe is exactly what I experienced with a customer that refused to keep their fuel tanks out of the rain.

These engines (20 hp) have a black, rubbery thing attached to the engine oil dipstick tube. It looks like some sort of large, inline, fuel filter. Honda calls it a "fuel resevoir". I think they put it there as a water separator. I can tell you it works great as a water separator because that's what I find in there with water contaminated fuel. If you have one of these contraptions, take it off and shake all the liquid out before trying to start your motor again.

What is happening (in my opinion) is that you have gotten water in your fuel and it has pooled in your float chamber bowls. The carb picks up fuel from the bottom of the bowl but if there is water there, you are feeding it water and no start. When you tilt the motor, as you say, and it starts, it's because you are sloshing the gas that is floating on top of the water, over and giving the carbureator a brief "gulp" of fuel. You need to check your tank for water contamination and drain the carbs and all lines including the fuel resevoir that I described.

Sadly, Honda carbs do not do well after ingesting water and it is also my experience that you will still very likely have runability issues until they have been thoroughly cleaned. But, you may have caught it early and a good fuel system flush and a dose of Sea Foam in the tank may be all that you need.

To verify water in the tank, I use a fuel line assembly with a primer bulb but with no fuel connector on the outlet. Since any water in your tank will pool at the bottom, water will be the first thing the in tank "dip tube" will pick up. The tank needs to sit undisturbed for a few minutes for the fuel to settle. If you pump several millileters into a glass jar and let it set only a few seconds, you will see the water and fuel separate. This isn't the only way to do it but it is my way and always yields results that I can show my clients. I feel like Merlin the Magician each time I hear the "audience" gasp when they observe the water that they have been unknowingly carrying around.

If you find water, you then need to find out where it came from. Sometimes it can be as simple as humid air condensing moisture into the tank. Or, it can be like my group leaving their tanks out in rainstorms with the vents open. If you suspect that the place you purchase fuel from is where you get it then you kinow what to do.
Good luck

jgmo has a good idea - he always does... The device he is referring to is a fuel chamber. The 90 HP's do not have them, they are unique to the 8HP - 20HP.

Drain your carbs into a glass and see what you have.

Mike

Thanks for all the suggestions!!!! I will try some of them this weekend and let you know. If anybody else has any ideas please let me know because i am open to anything!!!! Thanks again and in advance!!!!

now the starter went out so could not try these suggestions is the starter the same one that is on a car since it is the same block that is on the honda civic just wondering

I am not sure if the starters are the same. I doubt it. The Honda brand starter for the 90 is over $600. There are several aftermarket versions. Here is a link to an ebay site. http://cgi.ebay.com/ebaymotors/ws/e...6ffbaa1b1&rvr_id=&ua=WXI7&itemid=330428274438
I do not know anything about this starter or who is offering it, but it does list several part numbers from other manufactures that you can also check into.

The 90 HP starter will easily burn out if the motor is cranked for a long time. I always tell our customers...if the motor does not start or at least try to start in less than 5 seconds, do not keep cranking...something is wrong.

Mike

ok im getting a new starter and i am going to take carbs off and rebuild them again last year i put new orings in and cleaned carbs. this time i want fix any problems, would somebody please recommend the parts that would be subject to clogged or worn that need to be replaced in carbs. i want to get to the bottom of this problem and be done. thanks for any help!!!

sbryant,

We have a starter/alternator shop in town that rebuilds car and marine starters and alternators, trim motors, etc. My friend is an independent marine mechanic and uses them all the time with no customer complaints. It is a LOT cheaper than a new one. You most likely have a shop like that in your town. Might be an option for you.

My mother-in-law has a Honda BF90A outboard motor on her boat. At two of the (what I think are) Carberators, gas is leaking out. The gas is leaking out between 4 and 5 o'clock from the round, silver, piece of metal that's almost the size of a quarter. I would never attempt to fix anything on this but before we try to find a Mechanic I want to be sure there is actually a problem and that we didn't simply flood it.

She typically started the boat every couple of weeks through the winter up until her battery was acting up and died in January. There was a battery problem and we fixed it. New battery working great but engine won't start it does turn over though. Please help!!

Thank you,
Carl

It appears your floats in those two carburators are sticking open and allowing them to overflow fuel out the vent (where you see it).

It is flooding, but you have to get the float valves to seat before it can run right.

There may be other portions of your carbs that are already gooed up too.

Here is one thing that you can try. Sometimes it works for simple goo...sometimes not.

Get a can of Sea Foam and mix it in a small fuel tank.

Drain all the carburators and flush the entire fuel system using this tank leaving the carburator drains open until you are sure the fresh mix is getting to the carbs. Close the drains and sqeeze the bulb until it is hard. Let it sit overnight.

Then take a small block of wood and a hammer. Put the block up against where the carburator bowl and the carburator join together. Give the wood a couple of sharp taps, hoping that you will jar the float valve (needle) loose.

Drain the carbs again.

Then take your wood and hammer and do your tapping thing again. The first time was to jar it loose using the floatation of the float to push up the needle. The second time was to jar it loose using the float's weight to pull the needle down.

Now hook up some fresh gas and do some gentle tapping as you are squeezing the fuel bulb.

If you see no fuel leaking out, you were successful....but not necessarily out of the woods.

Try to start the engine. You may have to advance the throttle a lot more (maybe all the way) to get it to start. Be ready to pull the throttle back quickly if it does start. You may or may not even need to use the choke or you may have to use it a lot to keep it running.

This is a long shot. If you did not get it to start, at least you know you do have some issues with your carburators when you take it in. If you have to keep activating the choke to keep it running, you have some other blockages in one or all of the carburators. Be sure to let the mechanic know what you tried to do, so he (she) has at least a point of reference.

Hope it turns out to be simple.

Mike

alright thanks everybody for the help got the carbs. straightened out and she purrs like a kitten. now i was on a voyage the other day when the motor shut down and a sensor beeped , so i shut off the motor and discovered the was no water flow. i cooled the motor with some water and got towed back to my dock. i guess th impeller went out so i need to replace, could any body tell me the parts to replace in this situation and how difficult it may be and could it be done in water without pulling boat out since i dont have trailer. the local boat shops wont touch a honda so i have to do most of the work!!!! thanks in advance

It depends on your model. If you do not know the model, shoot me back your serial number and I will let you know.

I would recommend changing the entire water pump...not just the impeller. If you ran it for any length of time before the motor stopped, the housing and/or o rings etc are probably melted.

See the last page on this Honda Web site. http://marine.honda.com/pdf/accessories/ml.rerap45a.MAC_Water_Pump.pdf

You are going to have to drop the lower unit. I guess it can be done in the water if you have a dingy. It will not be easy. There are bolts and washers that are easily dropped.
At least I know that I would drop them.

Once it is off, there are probably missing parts of the impeller. You will need the backflush the system from the thermostat to hopefully, get those little pieces out of there. While you are at it, you should replace your thermostat if you have not changed it in a while.


Mike

Thanks hondadude you r a great help !!!! the sreial number is bbbl-4000667 i have a seloc honda manual that describes the rebuild and any help you can suggest is appreciated greatly!!! thanks again in advance

You have a BF90AX model. It is the cheaper of the two water pumps. Use the
06193-ZW1-B03 water pump.

Nothing real complicated about it. Just follow the manual as to how to take it off. If you can not find all the impeller pieces, you should look between the water intake and the water pump. Sometimes they just fall into the bottom part of the pump. Try to reconstruct your old impeller (if it is in pieces) so you are relatively sure that you got all the pieces.

Do not forget the backflush and check of the thermostat.

You should be able to find these parts on boats.net.

Mike