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Honda 50 Hp wot stumbling

shart777

New member
Let me share with you my woes … Bought an engine from a “real good guy.” Nothing he said about the engine to this point has been true ie thaty he replaced water pump just tuned, carbs cleaned etc ….
I bought an electro static cleaner for the carbs. Did those until you could eat out of them. Checked the tubes b/c everyone talks about cracks. Put them back together. Set the various screws to where they were when I took it a part.
Balanced the carbs to within a hair of their lives with my manometer.
Great idle, but when run-up it would die. So, I started backing out the mixture screws. It got better and better and then kinda not so much. I was making the adjustments on the water and running it up after each 1/8 turn out.
What is the starting point on the number of turns out on the screws? AND am I barking up the right tree? Thanks Scott
 
Idle mixture screws control air/fuel mixture at idle and transition to higher speeds.

If it is a 50A (that has a choke that can be activated)....the initial setting is 1 turn out for the idle mixture screws.

If it is a 50A, will the engine perc up and keep going if you momentarily activate the choke? If so, there is still a carb issue.

If it is a 50D, then there are other items to discuss

Squeeze the fuel bulb as it fails to see if the running improves.

Check your fuel for water.

Make sure the engine is coming up to temperature. If it is not to temperature, it will not idle well and could fall on its face.

Make sure the oil level is just below the full mark...not over filled.

Spark plugs new? NGK DR7EA ?

Checked compression? Could have a bad cylinder.

Have valve clearances been checked lately?

Make sure you put the manifold vacuum screws back in.
Make sure you have closed all three carb bowl drains.
These two seem obvious, but we all have forgotten...at least one time.

Just a few things to check.

Mike
 
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Mike .... Thank you for your help. More words work better for me than less.

I just went out and looked at the engine. When I left the boat ramp, I did not run the carbs dry. Will the fuel in them make its way into the oil crankcase? My dipstick has a higher reading then when i started out. It may smell a bit like fuel, but not positive.
According to the brief JIT "fuel pump or t-stat" is what I read in some older posts.
I noticed the fellow I bought this from removed the t-stat. So, there is none in there right now.
What type/viscosity oil is usede in bf50a 1998?
Anything special I need to know when/if I replace fuel pump diaphram?
Anything need to know about putting the t-stat in?
 
No, the fuel will not leak from the carb bowl to the crankcase. The oil was probably higher due to incomplete combustion and possibly carboned up rings.... both from running too cold. Your fuel pump diaphram could be leaking, but no thermostat is definitely a problem that needs to be fixed. It may not be the only problem....but it is a problem. If the bolts are hard to remove, you may have to use a blowtorch on the area to get them out without breaking them off.

First thing to do is put the proper thermostat in the motor. You should order parts # 9 and 11. They are the thermostat and the gasket. http://www.boats.net/parts/search/Honda/Outboard%20Engine/1998/BF50AW%20LRTA%20VIN%23%20BAZL-2000001/CYLINDER%20BLOCK/parts.html

Once you do that...it is time for decarbonizing...
Get a can a Sea Foam and mix the whole can in 3 gallon tank. Run the motor on that mixture. Hopefully, you can get it above 3500 rpm....run it good!

My guess it, your spark plugs are black by now. You should change them too. Use only NGK DR7EA. No substitutes...I do not care what the Autozone guy says.

Use SAE 5W30 oil (you could also use 10W30) but the owner's manual says to use 5W30. Page 79 http://marine.honda.com/pdf/manuals/31ZW4600.pdf

If you still think that your fuel pump is leaking...you can pull it off the motor...leave it hooked up and squeeze the fuel bulb until hard. See if it leaks. If it does, you will have to change the pump...it is not serviceable. If you order it be sure to get the o ring also (#22) http://www.boats.net/parts/search/H...TA VIN# BAZL-2000001/CYLINDER HEAD/parts.html

Mike
 
Mike Thank You very much. I just arrived home with t-stat and will begin working on it. It will be a few days before I can get on the water. I will post results then.
Scottt
 
Put t-stat in and engine runs better. It isn't stumbling now at wot. However, Now as I transition to wot it dies, unless I open throttle very very slowly - any thoughts?
 
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