My n600 - giving up the ghost?

[Steve]

You can try to use a hotter plug thatll burn the carbon off the tip but that is just a crutch to your ratio problem. Its the plugs that are causing you to run bad, its the carb that is affecting the plugs.

[dawn_and_darrian]

I'm unsure if that's the case. I replaced the plugs and hte problem persisted.
Matt Timion

[Steve]

thought you said you replaced the plugs and it ran fine for a few minutes, just long enough to foul the plugs again?

[dawn_and_darrian]

I never said anything about the plugs getting fouled again, but i did say it ran fine for a few minutes... maybe around the block twice.
But I'm having a difficult time believing that the plugs would get fowled after a few minutes when it took a month for there to be a performance decline previously.
Matt Timion

[zinc2u]

Matt,
You are driving me crazy! The car is screaming at you "I have a problem
in my intake system." Don't bother checking your timing belt or vacuum
advance or tire pressure. If you can replace the plugs and the problems go away
for even 30 seconds, the only place you can have a problem is in how the
air/fuel mixture gets delivered to the engine.
You have noticed the plugs get black (and you should see the exhaust is
black and sooty). You have a problem with the carburetor or the air
cleaner. Check (or temporarily remove) the air filter. Clean the carb, check it
float level, and verify the needle and seat are functioning properly. Make
sure the gaskets and o-rings are good and in place.
Dale
I never said anything about the plugs getting fouled again, but i did say it
ran fine for a few minutes... maybe around the block twice.
But I'm having a difficult time believing that the plugs would get fowled
after a few minutes when it took a month for there to be a performance decline
previously.
Matt Timion

[dawn_and_darrian]

Thanks Dale...
The carbs are kind of a mystery to me, so it's taking me a while to get the courage to read on how they work. I guess that's what I get for being a "youngin."
It's very possible the air filter is dirty and ready for replacement. I'm hoping nothing is wrong with the carb as the previous owner said it was just rebuilt by Mike O'Connor before he sold it to me.
Matt Timion

[dana]

Has Mike O'Connor confirmed he actually did some work on it? Dirty air
filter wouldn't cause this. (try running it without the air filter. what
happens then?)
Me and several other people have mentioned several diagnostic things you
should do (several emails ago as well as currently). Have you tried any of
them? If not, why are you wasting your time emailing rather than trying the
various diagnostic ideas you have been give by several --experienced--
people? If you have actually taken time to try them, you would have found
the problem by now. You have been given troubleshooting ideas on ignition,
fuel, timing and vacuum.
None of the things we have suggested you check will take more than 5 minutes
each. Don't just post messages, get out and work on it.
If this seems harsh, then maybe I have made my point.
Richard Morris

[dawn_and_darrian]

Richard,
Your message does seem a bit harsh, especially since I tried your suggestions first. The fact that you seem to have forgotten that I have already tried a few of these ideas and yet are more than willing to chastise me for "wasting my time" makes me less than enthusiastic to ask for ideas in the future.
And why havn't I asked Mike O'Connor if he did rebuild the carburator? Mike doesn't answer emails. I have emailed him a number of times regarding different things. I've emailed him asking to purchase his sedan, a carpet set, for more information on an engine rebuild, and the only time I could get him to reply was when I called him at his house.
I expect understanding from people when I state multiple times that the n600 (especially the carburator) is still foreign to me and that I am also very occupied with a number of other projects. What is a 5 minute fix for you might not be for other people.
Matt Timion

[zinc2u]

Hi Matt,
I have noticed with the advent of alcohol being added to gasoline, the
carbs are more susceptible to problems if the car is allowed to sit unused
for long periods of time. When I open the carbs, I see a powdery substance
in the bottom of the float bowl. I suspect it is the alcohol which is causing
the problems since it is good at sucking moisture out of the atmosphere and
mixing it with the fuel. So, even with a good carb, if it has been allowed
to sit for a period of time, it will become clogged. And that tends to
cause problems with the needle and seat section of the float. It doesn't seal
off properly and fuel is constantly leaking into the bowl and into the
engine. You have a rich mixture which fouls the plugs and yields poor fuel
economy.
If you were to detach the carb from the intake manifold and the air
cleaner but keep the solenoid connected and the fuel line, turn the ignition
switch to the "on" position (not the start position which is momentary). You
should hear the fuel pump click until the bowl of the carb is full of fuel.
Then the clicking should stop and you will not see any fuel spilling out of
the carb where it inserts into the intake. The fuel pump will still click
periodically (maybe once every 15 seconds) but it should not be a constant click.
This will let you know if the needle and seat is actually sealing without
opening the carb. If you operate the throttle, you should see fuel squirt out
of the carb indicating the accerator pump is working.
You still will not know if the float setting is correct unless you
measure it (requires removing the float bowl cover) or meausure it with an
air/fuel meter (or hydrocarbon meter or other method which is getting expensive and
too advanced for your needs). But it is important to know the needle and
seat are working properly since fuel flooding into your engine can be an
opportunity for an engine fire.
The stock fuel pump has a pressure of about 4 psi. If someone has
replaced this with a pump intended for fuel injection, the higher pressure could
be forcing fuel past the needle and seat and causing your engine to become
flooded with fuel.
Your problems seem to be due to a rich fuel mixture which can be
caused by
(a) a dirty air filter
(b) carb problem
(c) fuel pump with excessive pressure
You can verify if the problem is the air filter by temporarily removing it.
The fuel pump would require you to meaure the pressure or look at it to see
if it is stock (you may not recognize a stock fuel pump, though, if this is
your first time with a 600 car). I think the stock delivery rate was 250 mL
of fuel per minute which would give you a hint if it is a pump for the 600. I
suspect your problem is due to the carb needing cleaning and the needle and
seat and/or the float level needs to be adjusted. Also, are you using a
spark plug which is an NGK B8ES or equivalent. I have used NGK, Autolite,
Nippodenso plugs.
One more thing, what is the compression on your cylinders? They should
be about 160 psi.
good luck,
Dale
It's very possible the air filter is dirty and ready for replacement. I'm
hoping nothing is wrong with the carb as the previous owner said it was just
rebuilt by Mike O'Connor before he sold it to me.

[dawn_and_darrian]

Thanks for the very detailed explanation Dale. I've been reluctant to take apart my carb to investigate any problems until my other car is finished. i don't want to be stuck in the house with no means of transportation. I purchased some carb cleaner yesterday and i will try removing the air filter in a few hours when I have to go to the post office.
I know that the air filter is old (came with the car) and that the fuel pump is after market. It's a small box that looks nothing like the fuel pump in the parts catalog. I need to replace my fuel line anyway, so maybe I'll test the pressure sometime soon.
I will also use the method you described to ensure that the float is not stuck.
Matt Timion