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Discussion Starter · #1 ·
As part of a separate transmission cable replacement issue, I decided to hire a mechanic to rebuild my gunked up carburetor. In hindsight, I wish I had done it myself, but that is another story.
The engine now fires up on the first crank, but it wants to rev up high, and there is a lot of blue smoke coming out of the exhaust. There is also what appears to be a gas slick forming on the water behind the exhaust. And it sounds like it is spark knocking.
The oil pressure is 40 psi. No water in the oil, and the level hasn't dropped. The plugs look ok, except for two that are a bit black and dry(I am assuming from having to run it for an extended time with the choke, from a gunked up carb?).
Now the cabin of the boat smells like gas, and there appears to be a gas-like residue on the OUTSIDE of the carb and underneath it. The mechanic swears that there is a valve or piston problem and that the gas slick is an oil slick, but I know for a fact that it wasn't smoking/knocking/slicking before the repair.
I would greatly appreciate any insight on this problem. I will be checking the compression on the next trip down to the boat.
 

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burning rich, very rich. Float not set properly and idle/mixture not set properly. Don't waste your time on a compression check.

Be VERY careful with "the boat smells like gas" as vapors/fumes can cause problems.

Get it fixed, properly or do it yourself. At this point you would be better off ordering a new carb and replacing it yourself, than to give this person more money to "repair" what he has already broken. No more money for him, till it idles smoothly. He is not a mechanic.

While you may have a valve or piston problem, that is secondary to the carb getting repaired.
 

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burning rich, very rich. Float not set properly and idle/mixture not set properly. Don't waste your time on a compression check.

Be VERY careful with "the boat smells like gas" as vapors/fumes can cause problems.

Get it fixed, properly or do it yourself. At this point you would be better off ordering a new carb and replacing it yourself, than to give this person more money to "repair" what he has already broken. No more money for him, till it idles smoothly. He is not a mechanic.

While you may have a valve or piston problem, that is secondary to the carb getting repaired.
http://www.sailnet.com/forums/gear-maintenance/165858-drain-not-drain.html

I also loaned him my 2HP Honda 4 stroke, same result. Even after I cleaned the carb twice, I could never get it to run spot on. A $100 new Honda carb did the trick.

Paul T
 

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Rebuilding a carb is more like watchmaking than general mechanic work. And even carb shops seem to screw them up more often than not. A whole new carb can be expensive, but if you can get a "major overhaul kit" for the carb, that's often ~$100 and with a gallon of gumout and an afternoon of patience you can put it back in new condition.

The overhaul kit usually includes detailed instructions, Some drill bits of wire gauges and a small steel ruler to make adjustments precisely are required, nothing exotic. Some needles or fine brushes to clean out the passages, all easily procured. The hardest part is just being patient and methodical. Take the phone off the hook, use some boxes or bags so the small parts can't run away, and take pix with a cell phone or digicam if there's any doubt about how a stack of things go together.

When it is done, if everything is rosy again, you keelhaul the alleged mechanic.
 

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Rebuilding a carb is more like watchmaking than general mechanic work. And even carb shops seem to screw them up more often than not. A whole new carb can be expensive, but if you can get a "major overhaul kit" for the carb, that's often ~$100 and with a gallon of gumout and an afternoon of patience you can put it back in new condition.

The overhaul kit usually includes detailed instructions, Some drill bits of wire gauges and a small steel ruler to make adjustments precisely are required, nothing exotic. Some needles or fine brushes to clean out the passages, all easily procured. The hardest part is just being patient and methodical. Take the phone off the hook, use some boxes or bags so the small parts can't run away, and take pix with a cell phone or digicam if there's any doubt about how a stack of things go together.

When it is done, if everything is rosy again, you keelhaul the alleged mechanic.
Good points. I have been successful at doing what you described many times.
Had I known the Evinrude carb was $400 I would have pulled the old carb & brought it home with me for a try. But, due to distance & logistics, I just bit the bullet & ordered a new one.

You really don't have much to lose by trying a re-build/cleaning first, except you won't know if it worked until you re-install & test it, which takes time.
A new carb should work properly right out of the box, needing only low speed mixture & idle speed adjustment, as compared to a couple of hours "cleaning" it.

I like to lay out the parts, "up" side up, in sequence from left to right, in order of dis-assembly, on a large, clean towel to be reversed on assembly. Even if you have a good parts diagram or a good shop manual, good, close up digital pictures would be a big help. Suggest you "go slow" & be gentle. Some carbs have small spring loaded "check balls" most difficult if they spring out onto the floor. :D

Paul T
 

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Barquito
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How could the machanic suggest that there is anything wrong with the carb, other that what he just did to it? It ran OK before, and crappy after. My best (very uneducated) guess is that it is the float. If you take the carb off (easy), and split it in two (easy), the only thing that may fly out is the float and float pin. The pin should have a rubber pointed end that seats into a hole. The hole needs to be free of crap. Also, as most A4 posts mention at some point, see moyer marine site.
 

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"The hole needs to be free of crap. " And the pin needs to be "perfect" as well. If someone smashed up the tip (often "rubber") it usually needs a new one, which would be included in most overhaul kits. Or if the guy reamed out the hole with something too sharp, and it has been enlarged too much...that could ruin a carb and make it run rich forever.

You know boat projects, it rarely is over when you thought it would be.

Carbs are one reason that fuel-injected diesel engines became popular. (Until the owners get intimate with diesel and injection problems, anyway.(G)
 

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islander bahama 24
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As a marine mechanic I would hazard that the mechanic you hired didn't either set the float correctly or didn't set the needles correctly the choke is sticking or some combination of all the above the problem is not due to the valves or pistons. M2cw
 

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Blue smoke indicates oil. Running fast is idle adjustment or vacuum leak. A float set extremely low can cause fast idle but not smoke too. I would also suggest, from your description, you have other issues. Is the base gasket on correctly, vacuum connections, breather?
 

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islander bahama 24
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Blue smoke indicates oil. Running fast is idle adjustment or vacuum leak. A float set extremely low can cause fast idle but not smoke too. I would also suggest, from your description, you have other issues. Is the base gasket on correctly, vacuum connections, breather?
Actually when an engine is running extremely rich it will exhaust blue smoke with a distinct gas smell just like the op described
 

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Actually when an engine is running extremely rich it will exhaust blue smoke with a distinct gas smell just like the op described
Partially or un-burnt fuel will result in a black exhaust emission. Blue smoke = Oil and White = Coolant (steam). Of course the colors are subtle and I agree your nose is often a much better indicator when it comes to determining if your exhaust emissions are the result of fuel, oil, or coolant.

Certainly residue and the smell of gasoline in the engine compartment is cause for major concern. Had a customer with a very similar situation. Ended up he had connected the crankcase breather to the intake manifold which resulted in a high idle and blue exhaust emissions. ;)
 

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islander bahama 24
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Partially or un-burnt fuel will result in a black exhaust emission. Blue smoke = Oil and White = Coolant (steam). Of course the colors are subtle and I agree your nose is often a much better indicator when it comes to determining if your exhaust emissions are the result of fuel, oil, or coolant.

Certainly residue and the smell of gasoline in the engine compartment is cause for major concern. Had a customer with a very similar situation. Ended up he had connected the crankcase breather to the intake manifold which resulted in a high idle and blue exhaust emissions. ;)
I owned an auto repair shop for many years now I do marine to supliment my
VA and my cruising kitty What does it mean when a car is running to rich Running rich can be accompanied by a distinct exhaust smell, and in the extreme cases, some blue smoke
 

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I have taken the Zenith updraft carb apart several times for cleaning etc. It is quite easy to do - yourself. It is also quite easy to put the float pin in upside down - which will cause the symptoms the OP is experiencing - gas smell, dripping carb. Obviously I have done this.
A fuel tank with a lot of ethanol crud in it will also wreak havoc on the float needle, causing it to get stuck in the open or closed position.
There is an old expression: "If you want something done right you will have to do it yourself."
 

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"A fuel tank with a lot of ethanol crud in it will also wreak havoc"

Any crud will do.

But the most important point is probably that if you can SMELL gasoline, there's probably a fire danger.

1. Call insurance broker, make sure boat is overinsured.
2. Buy marshmallows and sticks.
3. Attempt to repair engine. Using bronze, brass, or beryllium-copper non-sparking tools.

Stick to the sequence and you'll be happy whatever the outcome is.(G)
 

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How about:

1.Opening every hatch, port, or other opening you can

2. Turn off the gas at the tank

3. Sop up any gas that is visible

4. Disconnect from shore power

5. Go have a long lunch

6. Remove carb & take it home to clean in a well ventilated garage

As others have mentioned, if you can smell gas, heap big trouble. :(

Paul T
 

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Discussion Starter · #16 ·
I went down again this weekend. The smell in the boat wasn't quite as bad, but when the bilge pump kicked on there was more residue on top of the water when it exited the boat. I know now that shutting the gas petcock should be done after each trip. I traced every line and every connection, looking for a leak. I am in agreement with you folks that there is a float problem. I did not start the engine. The carb had some wet residue on it, so I cleaned it up and also the area underneath it. I left a clean white paper towel. If that thing is stained next weekend, then that HAS to be it. Either way, I know I need to pull the carb.

ALSO, the mechanic failed to seat the choke cable bracket correctly. Not sure if this has anything to do with it, but I thought I would mention it.

Thanks again for your advice.
 

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islander bahama 24
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First, not all "professionals" are experts, or conscientious . I am not even close to being an expert on anything. Fortunately, my Dad started teaching me how to work on engines about 68 years ago. I don't know what your mechanical experience level is so forgive me if I am speaking out of turn.

I would imagine that Community Colleges, or something similar, offer small engine maintenance courses? That & a good shop manual or equivalent, can take you far. It is my opinion that the more work you can do yourself, with some limitations, the better off you are. Carburetors & distributors are generally fairly simple. However, a diesel high pressure injector pump is not. Older gas engines are relatively simple & easy to work on, in my opinion.

Paul T
 

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Newhaul-
"find a mechanic you can trust."
Reminds me of something Benjamin Franklin said, that any three men can keep a secret as long as two of them are dead. So any dead mechanic should be trustworthy, although, I'd still have reservations about some of them.

Paul-
I don't think you'd find engine courses in Community Colleges. In high school trade programs, yes. In "Trade Schools", yes. And some adult ed classes, like the New York State BOCES programs. But with a lot of the trade schools, the problem is that they are "student loan" mills, set up to take in anyone who is interested, get them signed up for government student loans, and then no one really pays a lot of attention to anything beyond getting those loan dollars. Sad to say, but a long-term racket. Asking a local car dealer's shop manager might get you a local referral, if there was one.
A good manual, and some you-tube videos, might be just as reliable a way to start.
 

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Newhaul-
"find a mechanic you can trust."
Reminds me of something Benjamin Franklin said, that any three men can keep a secret as long as two of them are dead. So any dead mechanic should be trustworthy, although, I'd still have reservations about some of them.
Paul-
I don't think you'd find engine courses in Community Colleges. In high school trade programs, yes. In "Trade Schools", yes. And some adult ed classes, like the New York State BOCES programs.
Just a guess. I took night courses in welding at the local high school shop. If the OP does a search, he can probably find a course. If he has basic mechanical knowledge & basic tool skills & a good shop manual, he should be OK.

But with a lot of the trade schools, the problem is that they are "student loan" mills, set up to take in anyone who is interested, get them signed up for government student loans, and then no one really pays a lot of attention to anything beyond getting those loan dollars. Sad to say, but a long-term racket.
Interesting, I didn't know that

Asking a local car dealer's shop manager might get you a local referral, if there was one.
A good manual, and some you-tube videos, might be just as reliable a way to start.
I forgot about you tube, right, I have seen some of those, like how to time a VW diesel, something I have done many times. Brought back some memories.
It is absolutely amazing what you can find on the internet.

Paul T
 
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