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2002 Honda 90 tough to start, idles finesm coughs at 1400rpm

C

Chris Williams

New member
This outboard has 400 hours on it, definitely had a lot of time in salt water. It had a fuel/wat serparator on it, but changed it and installed a Racor. Also all new gas in it now, but it is somewhat tough to start, I use the choke a lot and lately the only way I can get it to fire easily is with a little throttle in neutral. I don't know if this is normal or not. The engine seems smooth mostly when it is running but around 1400rpm when idling i hear the motor cough and it just keeps going, after a little revving and running its fine.

One other odd item is that the max rpm I can get with a new 3 blade prop is about 5400 rpm.

I pulled a wire off every cylinder as it was running and each one definitely made it run badly, so I am firing on all cylinders,

But I am wondering if maybe I have a slow jet clogged on one cylinder, not enough to cause big troubles, but I dont have those, just a little tough to start and the occaisonal coughing.

I would really appreciate any experienced you have with this motor.

I am wondering about pulling the carbs off and installing new jets and orings, cleanign them all up, but it looks hard on this motor.

Thanks in advance sorry for the very LONG post!
Chris
 
First...to start the 90 with carbs, you have to give it throttle in neutral. Give it a fair amount, but be ready to pull back when it starts. When it is cold, you will also need to continue to apply short bursts of choke until everything settles down. It is just the way they are.

The motor cough at 1400 may be a sneeze back through one or several of the carburators. If it is doing this when cold, but not when it is warm, then it is normal.

If it does it all the time, you may have one or more of the transition ports blocked. Try using some Sea Foam in the fuel with a little heavier dose than they recommend for normal use. It may clean out the blockage. You may also need to richen up the idle mixture. If it is a current motor, the screws have locks on them. If it is an earlier version with no locking caps, turn the idle mixture screws out about 1/4 turn. See how that helps the sneezingl

It may also be sneezing since your prop seems to be a little too big in pitch (assuming the motor is otherwise running ok). You should be able to run about 5500 - 6000 rpm fully trimmed out. If the prop the same size that you took off? Did the rpm's change?

If you put on a 17 pitch, a 15 pitch should get you closer to where you should be.

Mike
 
I have a 90, Honda dude is exactly right,w e have to give it throtle in nuetral to start.

Its great running motor if you don't leave fuel in it in winter, and arent good about keeping your fuel clean and add the stabilizers.

The good news is that if you do have to take the carbs off, its not that hard but is scary looking when you first start.

The factory service manual iss nice. I just bought the carb manual also and its nice to have.

Please let us know what you have discovered. Honda dude and the other guys here are Great!
 
davidnolan,

Thanks for pointing out the availability of the carburator manual. I thought it was only available to dealers. It provides great detail, step by step, with great pictures as to how to clean every type of marine carburator that Honda has. It also has great pictures showing the fuel and air flow through each carburator from idle, transition, and full throttle. Great to have if there is an issue at one of these points of operation.

For those looking in...the number at Helminc.com is TM044. It runs about $40 but is well worth it.

Mike
 
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Honda dude I can’t thank you enough! I just got this boat and have been struggling with the start. By doing it just like you said, she basically starts instantly! What a difference. Thank you again.

Give it some throttle, a little choke and left off once she starts, perfect! Thank you again!
 
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