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1999 Honda BF90A BBBl-1005669

I

illtww

New member
HI All.. Wanted to get some input on reviving this motor.


Situation:
1999 BF90a has been sitting for years... and years.... :( ***Fuel in carb bowl looks like molasses when I pumped new gas through. *** NOT GOOD!


Relevant Stats on Motor:
Compression PSI: (top of motor down) -- 181-171-171-180
NGK Plugs cleaned and replaced
Fresh Oil and Oil filter
Lower Unit In good Shape (Oil Replaced)
Hot Battery

Motor behavior:
It will turn over and TRY and run on 1 or 2 cylinders for 15 or 20 seconds but dies.

What I think it needs:
All 4 carbs Rebuilt / Replaced
Both Fuel Pumps rebuilt replaced

Do you know where I can purchase a rebuild kit for the fuel pumps or replacements that are reliable and or reasonably priced?
Donovan marine has a rebuild kit for the carbs. (Is that acceptable to use that kit? looks pretty simple)
 
I've done a bunch of these "resurrections", and the first place to start is a very careful cleaning of the carbs, followed by a total service. Oil change top and bottom (regardless of hours), oil filter and fuel filter. The carb cleaning can be a pretty daunting task for the uninitiated. Not because it's terribly complicated, because they aren't! You just have to patiently confirm every hole everywhere is clean/open! The "kit" isn't much. A couple of 0-rings (necessary) and the float bowl to carb. body gasket (also necessary). The "kit" does NOT include new float needles! Those are optional, kind of expensive for what they are, and thankfully are not a "must have" like the pieces in the kit. It's not REAL unusual for guys to have to go back through a set of carbs because they got in a hurry or were sloppy during the cleaning process. I've done a BUNCH of these, and STILL have to go back through a set on occasion! I'd say if you are reasonably handy, can muster up a healthy dose of patience, they make a good DIY project.

Fuel pumps don't have replacement parts available, making the fact they are pretty reliable a good thing!
 
Last edited:
Alan Hicks said:
I've done a bunch of these "resurrections", and the first place to start is a very careful cleaning of the carbs, followed by a total service. Oil change top and bottom (regardless of hours), oil filter and fuel filter. The carb cleaning can be a pretty daunting task for the uninitiated. Not because it's terribly complicated, because they aren't! You just have to patiently confirm every hole everywhere is clean/open! The "kit" isn't much. A couple of 0-rings (necessary) and the float bowl to carb. body gasket (also necessary). The "kit" does NOT include new float needles! Those are optional, kind of expensive for what they are, and thankfully are not a "must have" like the pieces in the kit. It's not REAL unusual for guys to have to go back through a set of carbs because they got in a hurry or were sloppy during the cleaning process. I've done a BUNCH of these, and STILL have to go back through a set on occasion! I'd say if you are reasonably handy, can muster up a healthy dose of patience, they make a good DIY project.

Fuel pumps don't have replacement parts available, making the fact they are pretty reliable a good thing!
Click to expand...

Hey Allen thanks!!

I will give it a whirl:

My Questions/concerns:

1. How to I "sync" the carbs after they are clean? Gauges or some other trick?
2. How do I get a part # for these fuel pumps? Can the diaphragm in them be rebuilt at all? They have to be smoked after looking at that fuel...
 
You'll need a vacuum gauge bank to sync the carbs, but may be able to skip that step if nobody screws with the settings during the rebuild. There is NO good reason to do that, but if you'd like to double check, there are cheap 4 gauge banks for less than 50 bucks on Amazon. I would give the pumps a try. I've had very good luck with them, even old ones. This site is pretty popular with a lot of guys - Boats.net Fair prices, most parts in stock, and quick shipping. See #12 here for pump assy. https://www.boats.net/catalog/honda...in-bbbl-4000001-to-bbbl-4099999/cylinder-head
 
Alan Hicks said:
You'll need a vacuum gauge bank to sync the carbs, but may be able to skip that step if nobody screws with the settings during the rebuild. There is NO good reason to do that, but if you'd like to double check, there are cheap 4 gauge banks for less than 50 bucks on Amazon. I would give the pumps a try. I've had very good luck with them, even old ones. This site is pretty popular with a lot of guys - Boats.net Fair prices, most parts in stock, and quick shipping. See #12 here for pump assy. https://www.boats.net/catalog/honda...in-bbbl-4000001-to-bbbl-4099999/cylinder-head
Click to expand...


Do you just do a clean on the old fuel pumps and run them. Seems like they may be pumping fuel into the crankcase slightly.


All the replacements are plastic pumps now. :/
 
Clearly there is a possibility that fuel could leak into the oil through the pump, but that hasn't happened to me yet. If I have a motor mixing gas with the oil, it's been a carb issue. No cleaning of the pump necessary. Try them as is....
 
Thread Update!

Rebuilt carbs (sonic Cleaned everything and all 4 carbs) and fuel system (new OEM lower filter and external Fuel/Water separator)..

IT seems to idle fine and rev ok in neutral on the hose (kind of lazy) [no backfiring etc]

New Problem:
Once in the water and under a light load it wont really rev past 3600RPMS.. It seems VERY LAZY as it revs up, also. There is no Honda Service Dealer within 1.5 hours of me so I am doing my best, here.

I did call the closet dealer and talked for afew mins with the head tech.

He seems to think it is the "High Speed Jets CLOGGED" Now I didn't run any wire through them or anything so I can pull them back off is that is recommended.

Question: Should I pull them back off and wire clean or air clean the high speed jets? Replace them all together?

Thanks!
 
Last edited:
illtww said:
Thread Update!

Rebuilt carbs (sonic Cleaned everything and all 4 carbs) and fuel system (new OEM lower filter and external Fuel/Water separator)..

IT seems to idle fine and rev ok in neutral on the hose (kind of lazy) [no backfiring etc]

New Problem:
Once in the water and under a light load it wont really rev past 3600RPMS.. It seems VERY LAZY as it revs up, also. There is no Honda Service Dealer within 1.5 hours of me so I am doing my best, here.

I did call the closet dealer and talked for afew mins with the head tech.

He seems to think it is the "High Speed Jets CLOGGED" Now I didn't run any wire through them or anything so I can pull them back off is that is recommended.

Question: Should I pull them back off and wire clean or air clean the high speed jets? Replace them all together?

Thanks!
Click to expand...


First thought is welcome to the club! Having to BACK through a set of carbs is NOT that unusual, even when you know what you are doing...

That's generally where I would start. THIS time, verify all openings are clear visually and with air pressure and carb cleaner. PROVE to yourself that opening is clear! Depending on a sonic cleaner to do that for you has come back to bite your butt.

That's still no guarantee to fix your issue though. The cleanest carbs in the world still will not tolerate low fuel pressure and problems with sucking air.
 
Alan Hicks said:
First thought is welcome to the club! Having to BACK through a set of carbs is NOT that unusual, even when you know what you are doing...

That's generally where I would start. THIS time, verify all openings are clear visually and with air pressure and carb cleaner. PROVE to yourself that opening is clear! Depending on a sonic cleaner to do that for you has come back to bite your butt.

That's still no guarantee to fix your issue though. The cleanest carbs in the world still will not tolerate low fuel pressure and problems with sucking air.
Click to expand...

When you say "sucking Air" Is that reference to the car gaskets or the intake gasket? Can you test that by spraying some carb clean close to them while running?
 
Sucking air past the intake gaskets is generally going to be noticed more as an idle issue, but sure, spraying WD-40 or carb cleaner works good to detect those.

By sucking air, I meant junk gas line fittings (quick connects in particular, look for wet/fuel stained), lines broken off inside the gas tank, fuel lines that have collapsed internally that won't flow enough fuel, etc.
 
Are you positive it's a 1999? The frame number you listed came up as 1997 on boats.net.
Not that I think it makes a big whoop as far as what you're doing with the carbs. You'll probably find the part numbers are the same for the 97 thru the 99 years.

https://www.boats.net/catalog/honda...a-vin-bbbl-1000001-to-bbbl-1099999/carburetor

The above parts page is for your frame number.

Make sure that you clear the low speed and high speed air jet passages as Alan recommends by physically blowing cleaner through them and following up with compressed air.

In case you don't know, those air jet passages are located at the forward flange of the carb body just above the throat opening. They are often overlooked by beginners.

I always recommend "backflushing" the idle, transition and high speed orifices with carb spray. Especially on neglected or long stored carbs. As was mentioned, you can't always rely on sonic cleaning to clear all the crud out.

From your compression numbers I'd venture to say that you've found yourself a winner!

Good luck.
 
Funny, when I was backing out of the parts page listing I noticed that it had a 1995 heading. WHAT THE???

But the listing only shows 1997 to 2007.

So, I went ahead and checked and the carb assembly part numbers are the same 1995 through 1999.....according to boats.net

Good luck.
 
jgmo said:
Funny, when I was backing out of the parts page listing I noticed that it had a 1995 heading. WHAT THE???

But the listing only shows 1997 to 2007.

So, I went ahead and checked and the carb assembly part numbers are the same 1995 through 1999.....according to boats.net

Good luck.
Click to expand...


I hope so! does anyone havea lnk to the service manual for this old beast? Want to also rule out the Coil Packs/CDI by checking OHMS range etc..
 
illtww said:
I hope so! does anyone havea lnk to the service manual for this old beast? Want to also rule out the Coil Packs/CDI by checking OHMS range etc..
Click to expand...

if not the service manual or a reliable place to buy one. A good way to TEST honda Coil packs? voltages values to look for?
 
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