Amphi Misses When Warm

[Tedredamphi]

I've run across the exact same symptoms on both a Jeep CJ-7 and a 1966 Mustang. Both times it turned out to be the COIL. Mustang engine would even run fine when hot with no load, but would run terrible and die when put in gear. You also do not need a ballast resistor when using the Pertronix Ignition.
What are you using for plug wires and coil wire?
Ted Matthews

 

[LSolheim]

I've got the standard Gordon Imports plug wires (replaced last year) and a
NAPA 7mm coil wire, also replace last year when I changed to the Pertronix
coil, Ted. There is no ballast resistor.



From: Tedredamphi [mailto:]
Sent: Tuesday, July 21, 2009 6:34 PM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



I've run across the exact same symptoms on both a Jeep CJ-7 and a 1966
Mustang. Both times it turned out to be the COIL. Mustang engine would even
run fine when hot with no load, but would run terrible and die when put in
gear. You also do not need a ballast resistor when using the Pertronix
Ignition.
What are you using for plug wires and coil wire?
Ted Matthews

 

[Tedredamphi]

I know that someone has already suggested it, but have you actually tried a different coil? I have 2 bad "Pertronix coils" sitting in boxes. One lasted only 6 months on a '66 Mustang.
Later,
Ted

 

[Ken Chambers]

Well, the carb does sit on an extremely hot manifold. Stupid design,
IMHO, making a one piece intake/exhaust manifold. The thick
insulating gasket under the carb helps a bit but there's still a lot
of radiating heat hitting the carb. A deflector shield would help.
It's possible the gas is boiling under very hot conditions but seems
unlikely in that you are able to reproduce the problem with each drive.

It has to be fuel, air, spark or maybe something mechanical. Sure
sounds more like an electric issue. You've changed most ignition
items but could have two bad parts. (rotor, cap?)

Any excess play in the distributor shaft indicating a badly worn
bearing or drive gear? It was mentioned earlier but how about the
engine ground connection or even the distributor to engine ground
resistance.

Do check this. The ground strap on the moving vacuum advance plate
(the plate that holds the points).

Did you ohm out the circuit from coil to ignition switch (it goes
through the timer relays). Or hot wire the coil to the battery during
the problem. Run the engine in pitch darkness to look for jumping
sparks. Pull individual plug wires to isolate cylinders.

Try Click and Clack the Car Talk Guys on Sunday morning PBS. Might be
a first for them dealing with an Amphicar. LOL

---Ken Chambers


On Jul 21, 2009, at 4:44 PM, LSolheim wrote:

> I was quite confident that it was the “tank vent” solution, which I
> had opened up a bit thinking all would be well. WRONG. And when
> removing the cap there was no sudden “suckage”. So today’s test
> drive was a bit longer than planned as although I was able to
> duplicate the problem, I was unable to diagnose or solve the issue
> and I had to wait at several stops for 15 minutes at a pop until she
> would run OK to continue. I was not able to dribble into the
> carburetor slowly enough, so my gas “pour” just killed the motor
> when already missing (if it had run better I would have confirmed a
> fuel starvation problem).
>
> Before the problem becomes mega-severe it seems that putting a load
> on the motor (trying to accelerate, turning on the lights or heater
> blower, etc) makes it worse. So perhaps we are talking fuel, but
> what would be heat or time related? A bad needle valve or float in
> the carb? I checked all of the hoses I could reach and none seemed
> to have the problem of collapsing or “sucking down”.
>
> Turning on the electric fuel pump has no effect (which should push
> fuel through the system at it is just under the tank) and from its’
> sound I can tell it is not running dry. I checked the oil and found
> no evidence that fuel was pumping into it, as if there were a bad
> diaphragm in the mechanical pump.
>
> This is severely limits the hot weather boating!
>
> --Larry

 

[LSolheim]

The only spare I have is the 43-year old original I took off last year when
I installed this one. Bad coils, eh? --Larry



From: Tedredamphi [mailto:]
Sent: Tuesday, July 21, 2009 8:37 PM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



I know that someone has already suggested it, but have you actually tried a
different coil? I have 2 bad "Pertronix coils" sitting in boxes. One lasted
only 6 months on a '66 Mustang.
Later,
Ted

 

[Tedredamphi]

Try a $20 coil from your local parts store. Just be sure to get one specifically for 4 cylinder engines. Coil for V-8 engines had different OHM rating.
Later,
Ted

 

[DavidC]

> I've got the standard Gordon Imports plug wires (replaced last year) and a

Have you got the side entry disi cap where the leads go in and are held by a
grub screw ? If so you MUST use copper leads and not the modern carbon type
or what happens is the carbon burns inside the lead where the grub screw
holds them. This creates a gap that eventually the spark can't jump and
engine slowly dies. It's worse hot as the leads become flexible and stretch
more. This was a big problem in the 80s when carbon leads were first
introduced but a lot of people have forgotten about it.

The roadside fix is undo each of the 5 grub screws inside the disi cap, pull
the lead out, cut of half an inch or so and push it back in and retuighten
the screw - that should sort the problem for a few hundred miles.

Re coils, the original will sometimes fail after a polarity change - always
a good idea to replace. Watch for counterfeit Lucas parts - there are a lot
about - re rotor arms, the only ones I would trust are:
Known good originals, (much bigger than the new type)
The ones supplied by Rarebits in the UK
or the ones now being made in red plastic, they might be available locally
in the US.

David C

 

[chasgould]

A new condenser should solve this. If that does not work, try a second new coil. A bad condenser will give these exact symptoms, and can eventually take out the coil as well. Even if you replaced these two parts before, try a second new condenser, and a second new coil, and this should solve it. My guess is the condenser, and not the coil.
Chas

Well, the carb does sit on an extremely hot manifold. Stupid design,
IMHO, making a one piece intake/exhaust manifold. The thick
insulating gasket under the carb helps a bit but there's still a lot
of radiating heat hitting the carb. A deflector shield would help.
It's possible the gas is boiling under very hot conditions but seems
unlikely in that you are able to reproduce the problem with each drive.

It has to be fuel, air, spark or maybe something mechanical. Sure
sounds more like an electric issue. You've changed most ignition
items but could have two bad parts. (rotor, cap?)

Any excess play in the distributor shaft indicating a badly worn
bearing or drive gear? It was mentioned earlier but how about the
engine ground connection or even the distributor to engine ground
resistance.

Do check this. The ground strap on the moving vacuum advance plate
(the plate that holds the points).

Did you ohm out the circuit from coil to ignition switch (it goes
through the timer relays). Or hot wire the coil to the battery during
the problem. Run the engine in pitch darkness to look for jumping
sparks. Pull individual plug wires to isolate cylinders.

Try Click and Clack the Car Talk Guys on Sunday morning PBS. Might be
a first for them dealing with an Amphicar. LOL

---Ken Chambers


On Jul 21, 2009, at 4:44 PM, LSolheim wrote:

 

[Midwest Amphicar]

Once again Larry -cause its "new" does not make it good. Just because it's Gordons does not give it an A rating. Plus poo happens. I installed a set of solid core wires (made in England) and within a hundred miles insulation had broken down causing poor running condition. My favorite headache fuel line with bend/crimp in it. At just the right time it would collapse. Then "fix' itself. My other all time favorite is the tab in carb for float. Upside down it can work just fine till .... Just let the Club pay for shipping to Celina and we will make it a tech session. Later Dave on my way to Celina unless its raing some more Wave.

 

[LSolheim]

I LIKE your thinking, Dr. Wave! I couldn't see any issue w/ the fuel line
on yesterday's adventure. I really don't want to disassemble the carb until
all else is ruled out. I'll bypass the mechanical fuel pump today and then
swap out the coil if that doesn't work.



From: Midwest Amphicar [mailto:]
Sent: Wednesday, July 22, 2009 5:15 AM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



Once again Larry -cause its "new" does not make it good. Just because it's
Gordons does not give it an A rating. Plus poo happens. I installed a set of
solid core wires (made in England) and within a hundred miles insulation had
broken down causing poor running condition. My favorite headache fuel line
with bend/crimp in it. At just the right time it would collapse. Then "fix'
itself. My other all time favorite is the tab in carb for float. Upside down
it can work just fine till .... Just let the Club pay for shipping to Celina
and we will make it a tech session. Later Dave on my way to Celina unless
its raing some more Wave.

 

[LSolheim]

Yes, that is the cap and they are carbon leads - I'll check into
replacements. I do have a Rarebits rotor!



From: DavidC [mailto:]
Sent: Wednesday, July 22, 2009 1:51 AM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



Quote:

> I've got the standard Gordon Imports plug wires (replaced last year) and a

Have you got the side entry disi cap where the leads go in and are held by a

grub screw ? If so you MUST use copper leads and not the modern carbon type
or what happens is the carbon burns inside the lead where the grub screw
holds them. This creates a gap that eventually the spark can't jump and
engine slowly dies. It's worse hot as the leads become flexible and stretch
more. This was a big problem in the 80s when carbon leads were first
introduced but a lot of people have forgotten about it.

The roadside fix is undo each of the 5 grub screws inside the disi cap, pull

the lead out, cut of half an inch or so and push it back in and retuighten
the screw - that should sort the problem for a few hundred miles.

Re coils, the original will sometimes fail after a polarity change - always
a good idea to replace. Watch for counterfeit Lucas parts - there are a lot
about - re rotor arms, the only ones I would trust are:
Known good originals, (much bigger than the new type)
The ones supplied by Rarebits in the UK
or the ones now being made in red plastic, they might be available locally
in the US.

David C

 

[LSolheim]

No condenser (or distributor shaft wobble issues), Chas, as the points &
condenser are replaced by the Pertronix igniter - although for the first
test drive on Sunday I did reinstall the points/condenser, but experienced
the same synptoms.



From: chasgould [mailto:]
Sent: Wednesday, July 22, 2009 5:13 AM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



A new condenser should solve this. If that does not work, try a second new
coil. A bad condenser will give these exact symptoms, and can eventually
take out the coil as well. Even if you replaced these two parts before, try
a second new condenser, and a second new coil, and this should solve it. My
guess is the condenser, and not the coil.
Chas

Quote:


Originally Posted by Ken Chambers View Post
<http://www.amphicar770.com/amphicarforum/images/techtwo/buttons/viewpost.gi
f>

Well, the carb does sit on an extremely hot manifold. Stupid design,
IMHO, making a one piece intake/exhaust manifold. The thick
insulating gasket under the carb helps a bit but there's still a lot
of radiating heat hitting the carb. A deflector shield would help.
It's possible the gas is boiling under very hot conditions but seems
unlikely in that you are able to reproduce the problem with each drive.

It has to be fuel, air, spark or maybe something mechanical. Sure
sounds more like an electric issue. You've changed most ignition
items but could have two bad parts. (rotor, cap?)

Any excess play in the distributor shaft indicating a badly worn
bearing or drive gear? It was mentioned earlier but how about the
engine ground connection or even the distributor to engine ground
resistance.

Do check this. The ground strap on the moving vacuum advance plate
(the plate that holds the points).

Did you ohm out the circuit from coil to ignition switch (it goes
through the timer relays). Or hot wire the coil to the battery during
the problem. Run the engine in pitch darkness to look for jumping
sparks. Pull individual plug wires to isolate cylinders.

Try Click and Clack the Car Talk Guys on Sunday morning PBS. Might be
a first for them dealing with an Amphicar. LOL

---Ken Chambers


On Jul 21, 2009, at 4:44 PM, LSolheim wrote:

 

[jfriese]

You need resistive (carbon) plug wires when you have an radio in your Amphicar. I have AM/FM radios in both my cars and need the noise suppression carbon wires provide. Dave Chapman and I talked about the carbon wire problem when I was having a problem (which turned out not to be the wires) some time ago. The fix for the carbon wire problem is to stab thin straight pins into the carbon conductor at the cut end of the wire that goes into the cap. The straight pin hugely expands the contact area between the piercing pin and the carbon and should eliminate the problem of a carbon burn in the plug wires.

John Friese
67 White
67 Red

 

[LSolheim]

Turns out the plug wires were solid core, but the coil wire was carbon. I
trimmed the ends anyway, but it made no difference.



I also bypassed the mechanical fuel pump with the electric fuel pump, also
made no difference.



Finally, I replaced the new Pertronix coil w/ a Triumph coil from Schucks
Auto. Also made no difference on the last test drive.



I may have to pull the carb if I cannot narrow down the problem. --Larry



From: jfriese [mailto:]
Sent: Wednesday, July 22, 2009 12:35 PM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



You need resistive (carbon) plug wires when you have an radio in your
Amphicar. I have AM/FM radios in both my cars and need the noise suppression
they provide. Dave Chapman and I talked about the carbon wire problem when I
was having a problem (which turned out not to be the wires) some time ago.
The fix for the carbon wire problem is to stab thin straight pins into the
carbon conductor at the cut end of the wire that goes into the cap. The
straight pin hugely expands the contact area between the piercing pin and
the carbon and should eliminate the problem of a carbon burn in the plug
wires.

John Friese
67 White
67 Red

 

[chasgould]

I still say chuck the Petronix, and install a fresh new coil, and a fresh new condenser, just to isolate whether the problem resides in the Petronix system. Then you can go elsewhere if that does not reveal an improvement.
Chas

Turns out the plug wires were solid core, but the coil wire was carbon. I
trimmed the ends anyway, but it made no difference.



I also bypassed the mechanical fuel pump with the electric fuel pump, also
made no difference.



Finally, I replaced the new Pertronix coil w/ a Triumph coil from Schucks
Auto. Also made no difference on the last test drive.



I may have to pull the carb if I cannot narrow down the problem. --Larry



From: jfriese [mailto:]
Sent: Wednesday, July 22, 2009 12:35 PM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20490] Re: Amphi Misses When
Warm



You need resistive (carbon) plug wires when you have an radio in your
Amphicar. I have AM/FM radios in both my cars and need the noise suppression
they provide. Dave Chapman and I talked about the carbon wire problem when I
was having a problem (which turned out not to be the wires) some time ago.
The fix for the carbon wire problem is to stab thin straight pins into the
carbon conductor at the cut end of the wire that goes into the cap. The
straight pin hugely expands the contact area between the piercing pin and
the carbon and should eliminate the problem of a carbon burn in the plug
wires.

John Friese
67 White
67 Red

 

[LSolheim]

Well the points (& condenser) I used on Sunday were from the previous (pre-Pretronix) install. Nothing more to lose. I was disappointed that today’s new coil didn’t do the trick, tho. --Larry

 

[SplitPersonality]

I agree Charles - though I have had coils be the problem more often, I have
seen a condenser - that simple little item - be the whole problem or at
least the initial problem which could then lead to coil problems. Vic


In a message dated 7/22/2009 8:26:39 A.M. Eastern Daylight Time,
writes:

A new condenser should solve this. If that does not work, try a second new
coil. A bad condenser will give these exact symptoms, and can eventually
take out the coil as well. Even if you replaced these two parts before, try
a second new condenser, and a second new coil, and this should solve it. My
guess is the condenser, and not the coil.
Chas


Quote:
Originally Posted by Ken Chambers
(mip://06e949d8/showthread.php?p=40239#post40239)
Well, the carb does sit on an extremely hot manifold. Stupid design,
IMHO, making a one piece intake/exhaust manifold. The thick
insulating gasket under the carb helps a bit but there's still a lot
of radiating heat hitting the carb. A deflector shield would help.
It's possible the gas is boiling under very hot conditions but seems
unlikely in that you are able to reproduce the problem with each drive.

It has to be fuel, air, spark or maybe something mechanical. Sure
sounds more like an electric issue. You've changed most ignition
items but could have two bad parts. (rotor, cap?)

Any excess play in the distributor shaft indicating a badly worn
bearing or drive gear? It was mentioned earlier but how about the
engine ground connection or even the distributor to engine ground
resistance.

Do check this. The ground strap on the moving vacuum advance plate
(the plate that holds the points).

Did you ohm out the circuit from coil to ignition switch (it goes
through the timer relays). Or hot wire the coil to the battery during
the problem. Run the engine in pitch darkness to look for jumping
sparks. Pull individual plug wires to isolate cylinders.

Try Click and Clack the Car Talk Guys on Sunday morning PBS. Might be
a first for them dealing with an Amphicar. LOL

---Ken Chambers


On Jul 21, 2009, at 4:44 PM, LSolheim wrote:






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[Midwest Amphicar]

While watching Dr. House last night on t.v. I figured out Larry's problem. Almost three months no clutch. Then heal problems, unable to leave room for ??. All the while Celina count down. Larry is suffering from parkinglotat eaglesenvy. Larry admit it. There is nothing wrong with Your car. You are missing the parking lot discussions. Only one cure......:005: See you in Celina Dave the Wave

 

[LSolheim]

Once again: very hard to argue w/ Dr. Wave!

Since I have replaced just about all I can think of, it is now close to time to pull the carburetor, which was last rebuilt in 2001 or so. Any specific advice as to what I should look for as I disassemble it?

Mike E. found a reasonably priced stash of new Amphi carbs some years ago. Does anyone know if there are still any available out there? I note my shaft bushings are beginning to leak onto the exhaust manifold again, so it may be time for replacement, sinc eI have replaced pretty much all else.

Thank you all for your gracious support during this NASTY experience! I just need the "magic bullet" of cure!

--Larry

 

[sach]

have you checked your valve clearence? if you don`t have proper valve setting, when the engine warms up you may have a valve or two staying slightly open when they should be closed, therefore causing a rough idle or a hard to find misfire.