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2006 Honda 30 BF30D Ser# BAUJ-1200xx rich idle

G

Glenn Clark

New member
I recently purchased 2006 30hp (BF30D Ser# BAUJ-1200xxx) that has the enrichment system (no choke) that tends to 'load-up' while idling. I have to put it in neutral and rev it a bit then it's good for another 5 to 10 minutes of idling along. It runs good at anything above idle.

From reading other forums by doing a google search, someone mentioned checking to make sure the motor oil hasn't been overfilled. I noticed mine is. As soon as I can get a new filter I'll be changing the oil and refilling it to the proper level. I'll post back if I see any improvement.

I also noticed by pulling the plugs that the top two seemed to be running rich as they were black. The bottom plug had the proper 'tea' color.

How can I troubleshoot this Fuel Enrichment system?

What else should I look for?
 
Looks like you are doing pretty good as a solo act.

It does appear that the bystarter is opening pretty good.

One other way to see if it is doing what it is supposed to......when you start the engine, the idle should be pretty high, then slowly come down to the proper idle speed...which should be 950 plus/minus 50 rpm in neutral.

Let's get back to basics...

You said that you were going to change the oil. When you do, be sure to use 5w-30 or 10w-30 mineral base oil (not synthetic oil). Make sure that the oil level comes to about 1/8" or so below the full mark.

Make sure your spark plugs are NGK DR7EA. No substitutes.

Perform a compression check, to see if there is anything going on in the cylinders or valves. You may now have carbon buildup on the exhaust valves and they may not be opening up enough to let all the exhaust out.

See if the oil is fuel diluted and see if the level increases with use of the motor. If so, the rings may be carboned up.

Check the thermostat to be sure that it is not stuck open, causing the motor to run too cold. If you have an infrared temperature gun, check the temperature of the engine. A cold engine will run rich.

If anyone has taken the carburetors apart already, the idle mixture screws may not be set correctly.

The carburetors may need to be vacuum balanced. If you have the gauges to do it, be sure to pinch off the two vertical hoses going between carb 1 to 2 & 2 to 3. And pinch off the hose going over the top of carb 1. You should have to increase rpm to keep the motor running, when you do....by turning the throttle stop screw. After you balance them and remove the pinching tools, you will need to reset the idle.

I know that I zipped through a bunch of stuff, but any of them could be the cause of your trouble.

Depending on what you find with the compression test, you may have to decarbonize the engine to clean up any carbon build up on the valves and/or rings.

Most of this is covered in great detail with great pictures in the Honda Marine Carburetor Manual. Well worth the money. http://www.amazon.com/Honda-Marine-C...A14VJQOXKKYWSY

Mike
 
hondadude said:
Looks like you are doing pretty good as a solo act.

It does appear that the bystarter is opening pretty good.

One other way to see if it is doing what it is supposed to......when you start the engine, the idle should be pretty high, then slowly come down to the proper idle speed...which should be 950 plus/minus 50 rpm in neutral.

Let's get back to basics...

You said that you were going to change the oil. When you do, be sure to use 5w-30 or 10w-30 mineral base oil (not synthetic oil). Make sure that the oil level comes to about 1/8" or so below the full mark.

Make sure your spark plugs are NGK DR7EA. No substitutes.

Perform a compression check, to see if there is anything going on in the cylinders or valves. You may now have carbon buildup on the exhaust valves and they may not be opening up enough to let all the exhaust out.

See if the oil is fuel diluted and see if the level increases with use of the motor. If so, the rings may be carboned up.

Check the thermostat to be sure that it is not stuck open, causing the motor to run too cold. If you have an infrared temperature gun, check the temperature of the engine. A cold engine will run rich.

If anyone has taken the carburetors apart already, the idle mixture screws may not be set correctly.

The carburetors may need to be vacuum balanced. If you have the gauges to do it, be sure to pinch off the two vertical hoses going between carb 1 to 2 & 2 to 3. And pinch off the hose going over the top of carb 1. You should have to increase rpm to keep the motor running, when you do....by turning the throttle stop screw. After you balance them and remove the pinching tools, you will need to reset the idle.

I know that I zipped through a bunch of stuff, but any of them could be the cause of your trouble.

Depending on what you find with the compression test, you may have to decarbonize the engine to clean up any carbon build up on the valves and/or rings.

Most of this is covered in great detail with great pictures in the Honda Marine Carburetor Manual. Well worth the money. http://www.amazon.com/Honda-Marine-C...A14VJQOXKKYWSY

Mike
Click to expand...

Thanks Mike... Manual is on order (I love Amazon Prime :) )

The motor isn't idling high during warm-up like I think it should. It starts then tends to 'load up' requiring me to 'blip' the throttle to keep it from stalling.

The oil will be mineral 10w30. No synthetic allowed in any of my engines (that is another story for another day).

All three spark plugs are NGK DR7EA. I cleaned them but have new ones on order. I'll perform a compression check when installing the new plugs.

What pressure should register during a compression check? I'm thinking 130 but I haven't been able to confirm.

I do have an infrared temperature gun, I'll check the temps just downstream from the thermostat. Let me know if there is a better location to test.

Previous owner said the carbs were "gone through" by the dealer about 1-1/2 to 2 years ago. The gaskets look brand new compared to other gaskets on the engine. He said he forgot to run the carbs dry and it sat all winter gumming them up. I have no reason not to believe him.

It also has new non-ethanol fuel in the tank although the fuel that was in it smelled fresh. New hoses, bulb and a new 10 micron boat-mounted water separator / fuel filter.

Glenn.
 
I usually don't like the phrase "the carbs were gone through" when being presented what sounds like a carb problem. But, oh well.

Not sure I would wait to at least DRAIN the excess oil or even do an oil change without the filter.....wouldn't hurt a thing....except the friday night beer kitty a bit. And, if you plan on using the outboard until you can replace the filter you shouldn't run it overfull.

Another thing you can do while waiting is to check the timing. It's visual and not hard to do if you have a manual for reference. One tooth retarded will give you this symptom. If the belt is pretty slack it's about that time to freshen it up.

You've got Mike's attention so you'll get it sorted out.

Good luck.
 
Check the compression with the throttle in in throttle only and full throttle. If your shifter (depending on the one you have) does not allow you to get to full throttle, disconnect the throttle linkage to the bottom carburetor. Pop the plastic piece (#2) holding the throttle rod (#3) onto throttle cam (#8). Then you can have someone hold the throttle cam in the wide open position.

Compression should be in the neighborhood of 128 plus/minus 14 psi.

Mike
 
hondadude said:
Check the compression with the throttle in in throttle only and full throttle. If your shifter (depending on the one you have) does not allow you to get to full throttle, disconnect the throttle linkage to the bottom carburetor. Pop the plastic piece (#2) holding the throttle rod (#3) onto throttle cam (#8). Then you can have someone hold the throttle cam in the wide open position.

Compression should be in the neighborhood of 128 plus/minus 14 psi.

Mike
Click to expand...


I went to do a compression check and realized mine doesn't have an adapter small enough. I'll get one asap.

I used my heatgun to check the thermostat and once the temps reached ~160°F it wouldn't get any hotter. Is this normal? I expected at least 180°F

After a good warm-up, I drained the oil and although the dipstick showed the level too high (above the cross-hatching), between what came out the drain and what little came from the filter all added up to almost 2 quarts which according to the owners manual is correct.

I installed a new filter and added exactly two quarts of oil and the dipstick again shows the level as being too full. This is with the motor about as dead center vertical as I could tell with my old eyes.

Also, before starting I made sure the bulb was pumped all the way up good and tight. I then started the motor (it started on the 1st try) and it did idle a little high for half a minute or so then noticeably slowed down a bit. I was also watching the by-starter with the heat gun during this time and it peaking in temps and the motor idling down all correlated. So maybe I just didn't have the bulb pumped up tight enough before when I said it didn't seem to idle high when started cold. I'll put this in the 'Aha!' file to do from now on because I usually run the carbs completely dry after every use. It still seems to be running a bit rich at idle, but I'll check again as soon as the new plugs are installed.

Thanks, Glenn.
 
Guess what? It is not a perfect world. If the specs say 2 quarts of oil, put 1 1/2 in and slowly work up to the point 1/8 - 1/4" from the top mark.

There is always some left somewhere in the motor.

Mike
 
Yeah, I haven't had one come out dead on the full mark in a long time. I've learned to "parse" it in a bit at a time when I know that I'm close.I always seem to end up with a small part of one quart being left over after an oil change. Same thing happens with my late model Kia. But it was ALWAYS dead on when I used to change oil in my old Chevys and Fords.

Just so you know......you are NOT "running" your carbs dry. You are only running the fuel level down to the point that the engine quits because the vacuum siphon in the main jet is lost.

If you want your carbs put away dry (as they should be) you must make use of the drain screws in the bottom of the float chambers that Honda provides for that purpose.
 
jgmo said:
Yeah, I haven't had one come out dead on the full mark in a long time. I've learned to "parse" it in a bit at a time when I know that I'm close.I always seem to end up with a small part of one quart being left over after an oil change. Same thing happens with my late model Kia. But it was ALWAYS dead on when I used to change oil in my old Chevys and Fords.

Just so you know......you are NOT "running" your carbs dry. You are only running the fuel level down to the point that the engine quits because the vacuum siphon in the main jet is lost.

If you want your carbs put away dry (as they should be) you must make use of the drain screws in the bottom of the float chambers that Honda provides for that purpose.
Click to expand...

I'll keep that in mind on the carburetors and I'll remove the extra few ounces of oil.

So is 160°F normal or is the thermostat malfunctioning? I expected at least 180°F. Heck, I'll just go ahead and replace it anyway, cheap insurance. ****Edit, I did a search and read the thermostat should be fully open by 160°F.

Thanks, Glenn.
 
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My guess is that your problem with idling is going to end up being carb "related". But you make an excellent point about operating temperature. I would be hesitant to tell you anything is wrong with your tstat though. I don't know how much you ran the engine or exactly where you're shooting the reading. I don't have the specs for your engine but I think that, ultimately, your instincts are good and she should be up in the 180 f. range. hondadude hss the correct answer. And your "cheap insurance" comment warms the cockles of my heart. Because....it's just so......RIGHT!
 
The 30D thermostat should be fully open at 158 deg F. Sounds like you are right on the money if you are measuring at the thermostat.

Idle mixture screws should be a 1 7/8 turns out.

Also, as Jimmy suggested...check the timing marks on the top of the powerhead. There is a T on the cam pulley to align with the T on the top of the powerhead while the mark on the flywheel with the mark on the cover mounting boss.

Mike
 
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