Honda 90, misses at low rpms, water in gas

igiveup1

Recruit
Joined
Jul 30, 2008
Messages
3
After running a 6.6 gal tank low and drawing a small amount of water into the fuel filter the engine now runs rough at under 1500 rpms. Mid range and full throttle runs fine. I suspect some water passed the filter and remains in carb bowls. Changed out the engine fuel filter and now installed a Racor separator filter with bowl. I just added an isopropyl alcohol fuel additive from auto parts store and intend to try to eliminate water from bowls simply by running engine normally. Does this sound like a reasonable attempt to fix?
 

AGENT 37

Petty Officer 1st Class
Joined
Mar 2, 2007
Messages
319
Re: Honda 90, misses at low rpms, water in gas

Drain the fuel bowls from the plug on the bottom of each carb to get the water out. I like to pull the output lines from the fuel pump(s) and spray brake cleaner in and then follow it with compressed air. I don't recommend leaving the brake cleaner in there for long I usually close up the drains and pump fresh fuel in immediately after. I then run for 15 - 20 minutes to make sure that all of the cleaner is out of the system because it is hard on gaskets and seals. The whole process is easy and only takes less than an hour. Don't accidentally turn the carb adjustments when you do it, make sure that you're on the fuel bowl drain plug otherwise you'll have a miss that will only get fixed by a link n sync.
 

hondon

Lieutenant Commander
Joined
Jun 11, 2001
Messages
1,922
Re: Honda 90, misses at low rpms, water in gas

Remember that you will now have water contaminated fuel from that tank all the way to the engine so you will have to purge that fuel delivery entirely.Easy enough to do.#1 change the engine mounted fuel filter and while you do that pump fuel from the primer bulb into a translucent fuel safe container,like you get at the auto paint store,before you reinstall that inlet hose to the filter.Do that until you get clean water free fuel out of that inlet hose.#2 purge the fuel pumps.Same idea but a little trickier as you have 2 fuel pumps with 4 outlets.Do'nt overlook this step though or you will be right back where you started.#3 purge the carbs,each one has a drain and a nipple that drains it.The bottom carb is a callenge to get a screwdriver on but it can be done.Do all that then hope for the best.
 

igiveup1

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Joined
Jul 30, 2008
Messages
3
Re: Honda 90, misses at low rpms, water in gas

So far, no good. After running dry gas through in 3 - 6 gal tanks of fuel and draining all the carb bowls (without getting any water out) the engine still misses badly under 2000 rpms. Local Honda shop says this is very typical of dirt in carbs. They see it all the time. I have rebuilt many carbs over the years but the shop says I won't be able to synch them without special vacuum instruments, etc. (And about $350.) So now I am on their waiting list.
 

igiveup1

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Joined
Jul 30, 2008
Messages
3
Re: Honda 90, misses at low rpms, water in gas

I had the carbs rebuilt and it now runs fine. Problem now is what the shop tells me about the ethanol issues. He says my 10 micron Racor filter isn't good enough to keep out the fine particles created by ethanol use. A 5 micron filter is required to keep my carbs from fouling again but no one makes a 5 micron filter. Anyone else have experience with this?
 
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