Smoking Honda

[CAVU]

I recently noticed that one of my 2002 40HP Hondas puts out a lot of smoke during a cold start. After about 15 sec it goes away and seems to operate normally. The other engine does not do this. Always happens after sitting overnight during cool weather. Has anyone else ever seen this problem? Or is it really a problem?

[Sea Wolf]

Ken-

I'm no engine mechanic, but the following is what I've been able to learn about this subject from 4-5 different discussion groups:

Sounds like the rings in that one engine or single cylinder may not be as tight against the cylinder walls as the rest. Have you been advised to use Ring Free or Techron in your fuel to avoid carbon build up in the rings? My Yamaha Owner's Manual specifically recommends the use of Ring Free, and the sales contract/warranty agreement has a place where you initial that you've been advised of the recommendation to use it regularly.

One of the problems with outboards and the fuel mixtures we're getting today with all the by products of the catalytic cracking process is carbon build up in the combustion chamber, as well as deposits in the fuel system itself, particularly if the fuel gets old from infrequent use. The problem is much worse in outboards compared to cars because of the lower operating temperatures in outboards due to the fresh water cooling.

To combat this, some engine manufacturers recommend the addition of Ring Free or Techron (both contain naptha, a carbon solvent as well as other solvents) to the fuel as well as a fuel stabilizer, such as Stabil, to stop the breakdown of gasoline additives as well as the unstable catalytically cracked molecules, and also to dissolve existing fuel system deposits. It is said that seized rings due to carbon build-up will dramatically shorten engine life.

A compression check when the engine is cold might show some difference between the smoking cylinder(s) and the others in that engine and the other engine as well, depending on how far the condition has progressed.

Techron, Ring Free, and Sea Foam are all carbon solvent fuel additives that can alleviate the ring seizure problem. They can be used in "shock treatment" doses to free up existing problems as well as added to fuel regularly in preventive doses. The shock treatment directions are on the cans. If after reading the directions you feel unsure about the procedure (big smoke producer) your engine dealer/service mechanic can do this procedure for you.

Hope this doesn't sound too alarming, but if what I've read about the subject is true, this is the advice that would be derived from it.

I would think that motors that are used for trolling a lot (lower temperature operation) should be especially closely monitored.

Joe.

[C-WEED]

Ken no boat motor expert here either and certainly not written in stone. But: Usually on a four stroke a puff of smoke on start-up is usually an indication of a valve guide seal seep. The reason you only see it on start up is because the oil seeps down thru the valve guide seal into the cumbustion chamber where it pools as the motor cools after use and the oil tries to drain down to the lower end of the motor from ontop of the valves. When you start the engine again the smoke seen is the oil being burned off. As the seep increases you may notice smoke during operation. It may or may not be leaking much during operation, as sometimes combustion pressure can keep the oil from seeping past the seal when it expands from heat and if the leak is slight.

One of the best ways to detect this is to get a bright light from astern on a dark night. With the engine at operating temp just look back over the engine towards the light. Smoke is usually easy to see under this condition. (just like when you look in the side mirror of a vehicle at night when another car is following. If your driving an oil burner you can see the smoke when driving or sitting at a red light).

A worn piston ring will usually smoke a bit more and at a more constant smoke rate as the oil gets past the piston rings to be burned on a constant basis as the motor is operated.

Is it anything to loose sleep over? Not really. Yet.... If ever. You can pull all four plugs (or is it three?) and look for carbon deposits on any plug. With the plugs out you should be able to see the piston tops with a flashlight. Rotate the engine if you want to bring each piston to top dead center (TDC) piston closest to top of spark plug hole. My engine piston tops with 180 hours look clean and basically brand new. If it is just one cylinder you may see carbon/oil deposits on the piston top. Also, closely monitor your oil level both before and after every full day use. See if you can detect any oil usage. If the smoke and oil usage is not excessive I don't think there is much concern. Of course Les may say you need a total rebuild. Then I would sound kinda dumb. And a compression check/leak down test while a little more involved can pinpoint the problem, also.

Good question Joe: Does Honda recommend some kind of de-carbon fuel additive? I have read else-where this need is due to all the fuel additives in our new gasoline mixes and outboard operating temperatures seem to be running cooler than cars. Hence no need for the additive in cars.

[gljjr]

Ken,

What color is the smoke? If it is "blue/grey" it is likely burned oil as indicated above. However if it is black you have an overly rich condition and should have the cold start system checked out (IE: choke on a carbs). If it is black I would definitely have it checked as you will eventually have problems starting it due to fouling the plugs. Since it is short lived and you don't indicate that the motor is running rough the problem isn't bad enough to foul the plugs completely yet.

Chris's post is very accurate on the valve seals. However I would be VERY surprised to see an outboard with this problem simply because there is little way for the oil to pool around the end of the valves like it does on a car as the engine is basically sitting verticle in comparison to a car. Of course the only outboards I'm really familiar with are the older Honda 4 strokes and my old Johnson and Merc 2 strokes. I guess that is why I opted for a 350 Chev in my North River. I sure with C-Dory had an IO option! At least I know how to work on them

[CAVU]

Thanks guys for the replies. The smoke is white and smells like my old two strokes. I pulled the plugs and they all looked normal to me (had a very light dry tan color on all three.) I couldn't really see the top of the cylinder in the bright daylight, I'll try again after dark and try to find a better flashlight. I rechecked my owner's manual and the shop manual and can find no reference to fuel additives being required or recommended. I guess I'll give the dealer a call and see what he says.

[gljjr]

OK, a white smoke could indicate that you have a blown head gasket or water getting into the cylinder in some way. I would DEFINITELY take it in and have it checked!

[Larry H]

Ken,

Here is a link to the Evinrude motor care products. I have used Engine Tuner to decarbonize outboards for many years. Follow the directions on the can.

Decarbonizing is a low cost way to start solving your problem. The process does produce lots of smoke and smell, though.

With the motor idling on a flusher or in the water, spray the Tuner through the carbs. Try to load up the cylinders evenly until the engine stalls, or is smoking heavily and then shut off the motor. Let it soak for an hour, then restart and run the motor for a least 5 min after the smoke clears.

Here is the link

http://parts.evinrude.com/info/parts/engine.html

[CAVU]

I've read posts before from people who have used these products. I'm not totally convinced they are needed or necessary. I have never read anything indicating that Honda recommends their use. My motors are 2002 but I have only about 87 hours on them. Does anyone else use these decarbonizing products? Does Honda sell a specific product for their outboards?

[C-WEED]

Ken: as Gary pointed out, white smoke is usually indication of water entering the internals of the engine. Three most comon ways for entry would be cracked or blown head gasket, cracked head or cracked cylinder wall. Not sure about the thermostat housing on these engines but there may be other ways as well. As water enters the combustion chamber it is burned and looks more like steam/smoke as you see coming out the tailpipe of a vehicle on a cold day.

This of course would be easier to see running the engine on a garden hose instead of submerged exhaust as in a lake. While it is possible for the crack to close when the engine gets hot one would think it normally would continue to smoke all the time instead of just after start-up as you indicated after a long sit. Usually the water ends up in the oil. Look for increased oil level, water bubbles on dipstick when cold or milky, thinning appearance. If the engine runs long enough to get good and hot the moisture usually evaporates off and no increase in oil level is detected.

If you are interested in do it yourself detection. Invest in a good compression gauge( around $30 can basically be used on any engine) and a repair manual. The tests are straight forward. Check each cylinder as per instructions. The cylinder with the leak will usually be appearant by lower compression as the pressure build on the compression stroke is vented out thru the crack into the cooling jacket. Another indication is an engine miss, rough running or power loss from the bad cylinder or cylinders. Sometimes the motor may run good as water injection has been used for years on aircaft for increased horsepower at take-off in a controlled manner.

[Sawdust]

Even easier IMO is a leakdown... any dealer will have the necessary equipment.

Dusty

[CAVU]

Thanks again for all the replies. I have an appointment with the dealer to have it checked out. I noticed a recent post from Halcyon noting that they have over 1900 hours on their 40hp Hondas. I hope I can reach that level with mine.

[digger]

Hi Ken, Ron here also in Spokane. I wouldn't have a tremendous amount of faith in some of the dealers here in Spokane. At the Honda shop I had asked if my 8 HP could be converted to remote throttle and shift, and they said "no". It took my talking with Les to find out that it could, in fact, be converted. I ordered my parts from Les and did the conversion myself. Also, Skipper Bill's, the Mercury dealer does not do any internal work, I found out, when I needed parts to overhaul a 6 hp Merc. I ordered them from Lake City Marina on the north side to get parts, and did the work myself -- learned mechanicing from my dad, and from years of reading manuals, and doing the work myself. There are dealers, and then there are dealers and service people who know their stuff. Seems like there aren't very many of the latter around any more. Ron

[CAVU]

Ron,
I know what you are talking about. So far I have not needed any service, but I would think they could do a compression/leak down test. I think I could do it myself except I don't have the tools. We'll see.

[C-WEED]

Ken: I am destined to be poor for life. So saving money is always important. Not to dog any shops or mechs out there but I have seen/been shafted/gouged enough times that I developed a habit over the years. Paying good money for parts that where never changed and bolts not being tight after a repair just kills me... I compare the price of that "special tool" to the price a shop would charge and the difficulty of the repair. Usually the tool/repair manual and parts are much cheaper. And my labor rate is free. The tool can usually be used on several applications. Use a tool more than once? Really makes it valuable. This is how I collect my tools. And the education is free that I learn along the way. The advent of the internet has made picking up tricks and tips easier than ever. I could bore you for ever on my experiences and an automatic transmission for example is usually something I would leave to an expert.

Having said that here are two recent examples: Wifes 1989 chevy cosica auto trans began to stall at stop light. Traced problem to the valve that locks and unlocks the lock-up torque convertor at 40 mph. Since it would not unlock, the car would stall at a stop sign. Any shop wanted over $500 to fix it. On the web I discovered the part costs $20. Side cover comes off trans. One bolt holds in valve. Remove and reinstall valve and hook up two wires. It took an hour and I took my time. I felt like superman

Toyota truck owners with 5speed manual listen up. My 1984 truck with 185,000 began to pop out of third gear. And a bit of a grind when shifting into third. (common problem) I was sure the shift forks where wore out and the synchroniser was shot. A quick scan on the internet and I learned a common problem. Remove the shifter, change the nylon ball on the end and most important, replace the disentigrated rubber "CUP" shaped seal under neath the shifter. Toyota dealer stocked the parts, no special tools, easy fix at about an hour. A rebuilt trans? $2000. This fix? $17.50. Shifts like a new truck. I can't help but wonder how many shops would say a rebuild is what I needed when they new of a cheap quick fix...

I guess my point in all this ramble is if you have the slightest curiosty as to what goes on inside that motor or anything else. Get a manual and study it. Librarys are a good place to look for free! Take your time, get the tool if needed and a friend with a cold one always helps. Auto Zone has lots of "special tools" you can borrow for free. If you think your over your head and don't feel comfortable go with a shop. But by educating yourself this way you can smell when a shop if BSing you. Just in talking with them they can detect that you are more informed and won't even try the dishonest route with parts you didn't need...

Just to keep this on boat topic. Just Saturday I go to get two sets of extra trailer bearings. I haven't had any trouble, but the best insurance is to carry extra sets in the glove box. I went straight to the most reputable parts place (CarQuest) in town in search of USA made bearings.

I take in the old bearings the seal and the hub. The guy breaks out a special tool. (Dial caliper) to measure the stuff. And he assures me of USA made bearings. I walk out with two small outer bearings, two large inner bearings and three seals. One seal to put all old bearings back together and two spare sets for the glove box.

When I got home I almost tossed the bearing sets in a zip-lock bag in the glove box for when needed, if ever. On a whim I broke out my dial caliper JUST to double check. I found bearings made in "ROMANIA". I found the two large bearings were 1/4 inch too large. And one of the three seals weren't even close. Imagine being on the side of some busy highway, in the dark two years from now trying to change this stuff. The one finger salute icon would explain my displeasure. (Can we get one???) My biggest fear is having to leave the CD on the side of the road unattended with trailer issues. The new generation thiefs roll up. Cut the cables with bolt cutters. Pull out a rechargable SawZall. (A demolition saw that cuts thru about anything) And they don't unbolt your outboard. They just cut the back of the boat off around the outboard. In about two minutes they are loaded up and gone. You end up with a ruined hull and a stolen outboard.

Well off to the parts place...

[gljjr]

Ken,

At this point I would do as suggested above and run the engine in question on the ear muffs. At least that way you will be able to verify if the smoke looks like "steam" or Blue/Grey oil.

As stated above you should be able to pick up a compression gauge from your local NAPA for a lot less than you can pay to have the job done. Then simply warm up the engine and pull all the spark plugs. Put the gauge in and crank the engine over 3 or 4 times. All cylinders should be within 5-10lbs of each other. I would expect them to be up around 130lbs or more. If 1 cylinder is low squirt a small amount of engine oil in the cylinder and test it again. If the pressure comes up then it is more than likely you have a bad ring on that piston. If it remains the same then the valves aren't closing properly.

At this point you can do a leak down test. Basically a leak down puts compressed air into the cylinder through the spark plug hole with the piston on TDC. You then listen to where the air is going. A leak down tester is not an inexpensive tool. It requires an air compressor and a special gauge that compares the pressure going into the cylinder against the pressure coming into the gauge. It is a pretty neat tool and works very well to help diagnose engine problems.

Oh, as for a remedy to remove carbon from the combustion chamber of an engine. When I was working as a mechanic in the late '70s there was an old guy that also worked there. One day I was doing a tune up on an old Mustang and he said it sounded like there was carbon buildup on the pistons and I should fix it. He then proceeded to grab a coffee cup and filled it with water. We took the air cleaner off started up the motor and put it on a high idle. We then slowly poured the water down the intake. While doing this you could see a lot of black smoke coming from the tail pipe. After 3 or 4 cups of water the exhaust was turning white and we stopped. The engine was noticably quieter and ran better. There was no need for any special chemicals. This of course requires careful administration of the water as too much could end up causing a hydrualic lock on the cylinder and in drastic cases could even damage the piston or connecting rod. In later years I did the same water injection but used a spray bottle instead. It took longer but still did the trick. Oh, and don't even think of doing this on a 2 stroke! It would very likely cause bearing failure as the air/fuel mixture is what lubricates the inside of the engine. The water would nullify the oil in the mixture causing major problems.

Another note of caution. Removing carbon deposits can actually cause more harm than good. If you had a large carbon deposit let go and start floating around in the cylinder it can really cause some damage. It is far better to try to eliminate the build up in the first place. Also, most of todays engines run lean enough that they should have very little problems with carbon deposits. Plus the additives the gas companies put in the gas helps to prevent this as well. I REALLY don't think carbon is your problem. Your engines are only 3 years old. It would take several hundred hours of a very rich mixture (by todays standards) to cause a carbon buildup. And even then the carbon buildup wouldn't cause the smoking you are seeing IMHO.