Honda gummed-up carb fix?

[cbhinkel]

I recently put my Honda BF50 back together after an extended period of just sitting around and waiting for a part from the "slow as molasses" Boats.net. Unfortunately, I had left my fuel line attached to the carbs for over two months and not practicing what I preach here on this board. (In my defense, I was only expecting a two week down time)

When I was doing some speed tests, the engine was definitely down on power and one cylinder was missing badly. However, the longer I ran the engine, this condition slowly improved and I suspect that at least one of the carbs was suffering from some clogging in the fuel circuits.

When I got back from that trip, I bought a 20oz can of carb cleaner.that looks to contain toluene, methanol and acetone amongst other things. Also, I ran the engine dry of gas when I was doing the flushing procedure. Next, I remove the fuel tank fitting on the gasline and placed the tube into the can of carb cleaner and used the primer bulb to fill the engine with the carb cleaner. I then started the engine and ran it to I was sure the fuel mixture consisted mostly of carb cleaner. The choke needs to be partly on during this as the carb cleaner chemical make-up consists of a higher level of oxygenation than straight gas. After that, I let the engine sit for about an hour to let the carb cleaner do its magic. I then put the fuel tank fitting back onto the gasline, hooked it back onto the gas tank and ran it so that it would be 100% gas again as the fuel source.

As the result, before I did this, the engine would not make it up to the rev limiter when in neutral and at WOT. After this carb cleaning process, my outboard would easily bounce off of the rev limiter (only momentarily!).

-Chris

[Tony D-26X_SusieQ]

Sounds like you have come up with a great fix there.

[Tom Root]

Thanks Chris!!!

I must openly tell the board, you always helped our local club, VYCSD, with informative and useful material!

Sounds like a good thing to know!

[cbhinkel]

Tom,

You are welcome! I've noted how much time and money it takes to fix this problem and tried to come up with an alternative for people here. (This doesn't even take into account a rip-off Honda repair center like JeffS' Woods situation!) It's problably not a 100% guaranteed fix, especially if there are corrosion issues too, but it's at least worth a try before moving forward with the carb rebuilds. This could also be incorporated into the yearly maintenance for the Honda outboard.

BTW - I used Berryman's B12 Chemtool carb cleaner as it's supposedly the best one out there. A word of caution though, I would recommend to not soak the carbs for more than an hour due to the higher level of solvency of the carb cleaner in comparison to straight gasoline.

-Chris

[argonaut]

Doesn't that stuff eat the paint off of the carbs?

[cbhinkel]

Sorry, when I said to soak the carbs, I meant to have the carb cleaner only to be inside the carbs, delivered through the fuel line. There shouldn't be any paint on the inside of the carbs, only bare metal.

-Chris

[craiglaforce]

Not to be as negative nelley, but just be careful since the carb cleaner will remove all the oil that lubricates the engine, while you are doing this. Kinda like running your car with no oil in the crankcase. Seems like a risky procedure.

[Sloop John B]

If I did this I would expect the motor to explode. You know, like when you overload it with ether starter fluid when it's 30 below. Might be better to mix this stuff with a little gas and run it. I'm sure somebody has an opinion.

For sure, if you had a two stroke, you wouldn't want to do this for what craig mentioned.

[dennisdl]

Hate to date myself - BUT, when I was younger and car engines were "simpler" - we used to do our own 'tune-ups' - change plugs, air filter, and do timing with a 'light', set the 'carb' by ear and occassionally used carb cleaner! When I did 'that'; for several minutes after starting (sometimes relunctantly on the motor's part) the air would be filled with blue smoke, and then white smoke - but LOTS of it !!!
Are those "symptoms" still there ???
Nevertheless, it seemed to work!!! I'm sure that is still the case....

[John McDonough]

Every last sail of the year, I pull my gas line frommy Honda 50 and let the motor idle at 1500 rpm till it runs out of fuel.. When I get home I also open the small screw onthe bottom of the carb to get the last few drops out. 10 years old now and still no problem yet, but I haven`t used my boat yet this year. I would suggest that after using all those chemicals, I would change the oil. Anything that leaks past the rings ends up in the oil.. 25 years ago I blew my cars engine by putting a engine-cleaner in the oil. It said to add 8oz to 5qt of oil. I didnt read the rest of the directions,, it said run engine for 15 minutes and drain, I put it in and started a long trip, after about 50 miles I noticed that going up hills it was losing power, I looked in the rear view mirror and saw a smoke cloud. I called a mechanic, he said it was totaled. all the seals leaked. If it isn`t broke don`t fix it or at least read the directions correctly.

[cbhinkel]

All good feedback and concerns which I will respond to.

craiglaforce: By the time the carb cleaner is in the cylinders, it is finely atomized as a fuel/air mixture which I strongly believe wouldn't be capable to remove the oil coating from the metal surfaces. Also due to some residual gasoline in the fuel line, it's never probably at 100% anyhow. Lastly, the engine is run at a no load condition during the entire process which doesn't last that long to begin with.

SJB: I'm curious why you would think it would explode? I'm just substituting once fuel source for another in its existing metering device that just has higher oxygen content. It's not like I'm haphazardly dumping the carb cleaner down the carbs or using nitro-methane! FWIW, if you go and pay $50-$100 for a fuel injection cleaning at your local monkey garage, they will disconnect the fuel rails from the gasline and inject a carb cleaner type of solution into the fuel injection system and run the engine, very similar to what I propose here. However, they will use a cleaner that lacks methanol as that harms catalytic converters.

dennisdl: No smoke or anything and the engine ran like normal once I slightly put the choke on to compensate for the lean burn from the oxygenated fuel. However, the exhaust odor was slightly different hinting to the carb cleaner being burnt inside of the engine. I made sure the choke was not overdone here though as you don't want to dump raw carb cleaner solution into the cylinders for the reasons that craiglaforce mentioned above.

John Mc.: I don't think any or a very small indetectable amount of the carb cleaner (the Berryman B12 stuff can also be used as the crankcase engine cleaner too) made it into the oil since this is done with a small amount of cleaner relative to the hundred+ gallons of gas that is run through the engine between oil changes. The little bit that might have made it would probably evaporate anyhow by the time the oil came up to operating temperature due to the higher vapor pressure of acetone and some of the other components. In your case, you physically dumped a significant amount of the cleaner into the crankcase, and I'm sorry to hear about your demise. Today, I test ran the engine again and it felt strong like yesterday. Also, I just change the oil last week with fresh Mobil1 5W30 full synthetic. I pulled the dipstick and everything looked and smelled normal. I finished up the maintenance by synching the carbs and once I get a lower pitched prop, I will try again to see what my Mac19 is capable of.

Overall, I feel I'm an accomplished mechanic and that this procedure could be beneficial for certain people if done correctly. It defininitely worked for me. However, if you're risk averse and/or don't even know what a "Vise grips" is, I would suggest for you to pony over the $500 or so and have your Honda dealer rebuild the carbs. In addition, I agree that 2-stroke owners should NOT utilize this process.

-Chris

[jklightner]

I've done basically the same thing. Mix a can of "Sea Foam" with a gallon of gas in a small gas can and run it through, let it sit, then run regular gas thru to flush out the cleaner. Then I do my 50 hour maintance which includes oil and filter change, lower unit lube change, and plugs clean and regap or replace. No damage to hoses or other parts. I run it with the prop off, because I pull it to grease and re-torque also, and in a tub of water that covers the lower unit and the hose muffs on. Mine is a Mercury/Mariner 50 HP Big Foot.

[craiglaforce]

Don't know why I was thinking you had a 2 stroke. Duh, its a Honda, so 4 stroke. Never mind, there is oil in the crankcase.

[Rich Smith]

Speaking of gummed up carbs...

First, let me say that I consider it a major accomplishment for me to winterize my Honda 50 myself which will give you some idea of my level of competency around outboards (not much!)...

However, I came accross an interesting theory about winterizing to prevent the carbs from getting gummed up. I have always followed the manual instructions including the step where I unplug my gas source and allow the motor to run out of gas...

However, last winter I needed some other stuff done to the motor that is beyond my comfort levels so I took my boat to a licensed Honda Mechanic and had him winterize it while he was doing the other work...He told me that he no longer runs the engine dry but adds some gas preservative to the gas and runs that through the engine so that there is gas and gas preservative in the carbs all winter...He said that he'd had problems in the past with Honda carbs getting gummed up when he followed the manual and that once he switched to his method he'd never had a problem (he'd been doing this for years)

Well, I was a little sceptical but he's the mechanic...When this season started, I closed my eyes and turned the key half expecting problems but I must admit the engine started on the second try...

Any comments on this method?

[jklightner]

I too add Stabil to the tank and run it thru the carbs. I also run my engine once a month in the driveway during the winter.