Rapid loss of power and engine dies

[Kelly]

In testing my late model A4 last night I had the following results: very easy starting (much easier than before repairs), "explosive" acceleration in neutral (as Don says) with no limitation in RPM (2000rpm+), steady running in forward @ 1200rpm for fifteen minutes with sudden, rapid loss of power and engine dying as if a rope had wrapped around the prop shaft.

Engine turns over strongly immediately after the shutdown but will not fire. 5-10 minutes later engine starts easily and cycle starts over.

Recent changes: new choke cable (most certainly responsible for the easy starting), cleaned and sealed aluminum gas tank, replaced all fuel lines- pickup tube clean and vent clear. Clean gas. New Racor filter/separator. New polishing filter (clear/plastic for initial troubleshooting).

When first running the fuel pump without the engine to prime the fuel lines, it took a while for fuel to reach the polishing filter (4 minutes?) but seemed reasonable given the volume of fuel to move. Successful priming with only the electric pump made me believe the fuel lines/filters were tight.

I'm thinking this should be fuel related. The plastic filter looks to be almost empty, even while the engine is running. Running under load may be overpowering the fuel supply.

Planned checks: bubble in the Racor filter preventing consistent fuel flow? Carburetor mixture lean? Check plugs? Clean prop (looks fuzzy with growth but no barnacles).

Ideas?

[Dave Neptune]

Kelly s you worked on the fuel lines re-check the clamps for a good seal as you could be drawing in air reducing fuel flow. If all checks out fine as soon as the symptom shows again check for spark. Usually if the engine stumbles to a stop or stall it is fuel and if it is ignition it will usually just turn off and can come back on when it cools off a bit.
Since it took so long for fuel to get to the carb I would lean to fuel delivery as the culprit in this case.

Dave Neptune

[sastanley]

Kelly,

Four minutes seems excessive to me, but I use the mechanical pump.

When I accidentally forgot to open the fuel petcock at the top of the tank (and subsequently ran the engine for 8-10 minutes as it ran off the fuel in the lines & Racor filter) it only took about 20 seconds of starter cranking for the mechanical fuel pump to re-prime the fuel system and start the engine. I have 1/4" fuel lines, about a 6 foot (2m) run from the tank to the Racor & ~18" (1/2m) run from the Racor to the fuel pump, with the MMI polishing filter stuffed in between the pump & carb.

I've never used one of those Facet pumps so I am not sure what is considered acceptable.

[Kelly]

O.K.- I did a lot of testing this afternoon. I skipped work and headed to the boat...

Here goes:

I added an in-line priming bulb to hopefully incriminate or exonerate fuel delivery in the process. I also replaced my old "suspect" on/off valve.

The engine starts like a dream. One of my dreams, anyway. Three seconds on the starter with full choke and it catches right off. I can close the choke within seconds and the engine is happy. 40 psi on the oil.

After warming up in neutral to 160°F I run up to 1500rpm in gear.
After four minutes the temperature is up to 200°F.

I slow to an idle in gear (900rpm) and the temperature settles at 185°F.
After five minutes the engine sounds to "stumble" a bit (rough running) and rpm drops to 600.

I put it in neutral and run at 1200rpm. Temperature drops to 180°F.
After two minutes I put it in gear and the engine stalls immediately.
Cannot restart (engine turns over but no fire).

I decide to check the plugs: all four are dry and lightly coated with a black soot (looks good to me).

This takes me 20 minutes, after which the engine starts fine.
I run it at idle in gear (900rpm) for ten minutes and the temperature rises to 160°F and stays there. Oil pressure 13 to 15psi.

I then run at 1200rpm for ten minutes and the temperature rises to 185°F and stays there. Things look good.

I run up to 1500rmp (18psi) and the temperature reaches 200°F+ after five minutes.
I quickly drop to idle speed and the engine immediately stalls (I don't even have time to give it more gas). No restart (even with priming of fuel line).

Hang in there, almost done.

Thirty minutes later I get a very rough start. The choke doesn't help but the engine smooths out after about 30 seconds.

I run in gear at 1100rpm and after 3 minutes I have 175°F and 15psi.
13 minutes later at the same settings, I get some roughness and the tack reading dances a bit. Temperature is 180°F. The engine dies quickly just like the previous times.


So, with the priming bulb I made sure the clear filter had gas in it several times during this process and the engine stopping occurred with gas in the filter. Also, sufficient gas didn't help me to restart after the engine failures.

I'm thinking this has to be temperature related. Perhaps temperature perturbs the carburetor (vaporized gas??) thus causing stalling and a no start?

I know I'll get the "coil" comment but I've had engine cut outs before that definitely sounded electrical (like turning off the key). These are more like I said earlier, something grabs the prop and the engine just can't overcome the effort.

I was hoping to get out this weekend before leaving town on vacation with the family- major frustration.

As usual, any ideas? (sorry this entry got so long!)

[lat 64]

Kelly,
Here's some stab-in-the-dark ideas. Not necessarily good ones.
dirt in main jet leaning out mixture and running hot,
oil pressure drops and safety switch is dropping voltage to ignition or fuel pump, and I agree with Shawn—four minutes is too long.

Imagine this:
You prime the float bowl with fuel so the engine starts fine.
The bad pump won't keep up and the engine dies.
The engine runs too hot because carb is starved-for-fuel-lean and/or cooling system is on the fritz.
The failing part in the ignition won't work when the engine is hot so you can't start 'til it cools.

Perhaps you are chasing two or more problems at the same time.
This is probly not much help. You have a real puzzler.
Russ

[Kelly]

Russ,

I did adjust the fuel mixture at the carb, both leaner and richer, and didn't seem to get any changes in the results. I too am eyeing the carb and am contemplating opening it up.

When you say "the failing part in the ignition" are you fingering the coil. Or are you thinking of something else? I don't have a spare with me on the boat but a quick swap after a stall would answer that one I suppose.

(side note: I don't really lean toward the ignition side as my "rough start" 15 minutes after a stall with gradual smoothing out doesn't seem logical if this were electrical/heat related.)

I think I pretty much exonerated the fuel delivery (up to the carb) by using the priming bulb when the engine was running.

I have to admit, I'm really at a loss.

[Dave Neptune]

Kelly, if the plugs are sooty the mix is to rich, especially at idle. That could be why it starts cold so easy! If you adjust the idle mixture screw you should feel the effects at idle while turning the screw. If not time to redo the carb. Tht carb is quite a simple one just be sure you have access to an air gun~~very important.
There also seems to be a heating problem which could be related IE a vapor lock in the fuel line however it is doubtful or oil preassure dropping to low and cutting out the ignition via the O/P switch if you have one.
Seems to be more than one problem.

Dave Neptune

[sastanley]

Kelly...I'll say it...."coil" - unlike most common coil failures...mine did not die instantly, but faded like fuel. We pumped the crap out of the fuel line bulb to no avail. While cruising, I had three friends with extreme levels of experience help me rebuild the fuel system. One said..."hey, mount your spare coil & let's get the wires extended just in case." (yes, beer was involved.) It quit, (faded), I moved the wires over and ran it 8 hours straight on the next cruise. Just sayin'


I agree that it likely isn't a fuel delivery. I also didn't dig back thru this entire thread and all the details, but I think I read somewhere that the condensor might cause similar symptoms.

[roadnsky]

Originally Posted by Kelly

I did adjust the fuel mixture at the carb, both leaner and richer, and didn't seem to get any changes in the results. I too am eyeing the carb and am contemplating opening it up.

When you say "the failing part in the ignition" are you fingering the coil. Or are you thinking of something else? I don't have a spare with me on the boat but a quick swap after a stall would answer that one I suppose.

Kelly-
A lot of good suggestions from everyone. All to be checked out.
To answer your question to Russ, he was suggesting the same thing Dave did...
the oil pressure could be dropping too low and the oil pressure switch on your fuel pump kicks off until the engine cools and you have enough pressure again.
Assuming you have an electric fuel pump? If so, an oil pressure switch in-line too?

Something is not right in that carb as Russ and Dave said. Turning the idle mixture adjustment just a half turn either way should have an effect.
If not, time to get in there.

I'll second or third the opinion that 4 minutes to prime is way too long.
I've been doing work on my fuel lines/system lately and from bone dry it takes my RED HOT Facet 30 seconds or so, tops, to have fuel to the carb.
Double check those lines for air?
(Also ignore the red hot remark. I'm just being cranky )

AND, as Shawn suggests, you could be having coil issues.
If you have a spare, then maybe try it to see if the problem stops.

It also sounds like you're having some cooling issues or at least will have some on the horizon.
Other than the possible oil pressure switch on the fuel pump, I think its separate from your stalling problem.
When was the last time you gave the cooling system a once over?

[hanleyclifford]

Last trip south I spent a week anchored up just around the corner from where Shawn lives. I was going thru exactly what Kelly is going thru now. I rebuilt the carb, pulled the head, cleared the exhaust system --you name it. In the end I put in a new condenser (replacing another new condenser), and simply drove away. I was in shock that I could have overlooked something so obvious (and snow was falling in Solomons!).

[lat 64]

Originally Posted by Kelly

When you say "the failing part in the ignition" are you fingering the coil. Or are you thinking of something else? .

I'm not pointing to anything in particular, I once chased a problem caused by a distributor cap with a teensy tiny hole in it for almost two years. By process of elimination you can have everything tested for sure. Roadnsky summed it up well—more than one problem?

Really wishing you good luck.
I'll be in the mountains 'til July 7th—no internet there.

Happy fourth all,
Russ

[Kelly]

Dave/Jerry: My ignorance is showing. I thought the plugs looked good but after your comment and some searching on the net my "black/sooty" plugs should be indicative of a fuel problem (too rich?). I did adjust the idle mixture screw yesterday and the engine reacted...not unlike when I rotate the distributor. (I was unclear in my earlier post- I meant to say the idle mixture adjustments didn't seem to affect my subsequent shut-downs). Now I'll go back and clean the plugs and adjust the idle mixture as per the Moyer manual.
Also, I do have an oil pressure switch. After one stall, I bypassed the switch to make sure the fuel pump was running but was still unable to start the engine.
(Side note for Jerry: my electric fuel pump stays cool and after all my testing yesterday was only slightly warm to the touch)

Shawn: OK, as soon as I get to my spare coil I'll try out some tests. I didn't know you could get a "slower shut down" with a coil problem. I have electronic ignition so no more condenser problems...

Russ: I've got my work ahead of me...I too am heading to the mountains so I won't get to it all immediately. With your help (everybody), these problems will get resolved.

[Dave Neptune]

Kelly, you have a bit of good advise here and more info will develope. If you are making a differance with the idle "air" screw be aware that as you get the carb closer to correct freo being to "rich" the lil beastie may take a bit longer to satrt. It is the nature of an "up-draft" carb application as it needs to move the fuel/air "UP" to the manifold.
Once you have the idle leaned down the plugs should look a chocolate color on the ceramic insulator on th electrode. The lighter the color the better off thing are.
Then get the timing close and leave it alone for a bit, if you are to far retarded it could cause a bit of a temp problem and may be a contributor to it not necessarily the cause.
Sort out one thing at a time then you know what gave what result.
It's just something basic and maybe more than one.

Going sailing for a few days to enjoy my mooring at the island and a big Corsair YC party. This year I'm in the big hat and responcible for the event.

Dave Neptune
Commodore

[Kelly]

Dave,

Thanks for the note and advice, but quit calling me "too far retarded" With some perseverance and grease under my fingernails, I'll get this sorted out...

Enjoy the weekend!

[ndutton]

Originally Posted by Kelly

Dave,
Thanks for the note and advice, but quit calling me "too far retarded"

Too far retarded is assumed and applies to all of us.

We own sailboats!! And old ones at that!!!

[Kelly]

I was back to my testing today to see if the problem fixed itself. No such luck.

After 25 minutes of running in gear the engine started running rough and stalled within 5-10 seconds.

20+ psi oil pressure
175°F fresh water temp.
1000 RPM

The engine would not start after the stall, including after priming with the bulb.

The fuel system is new/cleaned from the tank to the engine excluding the pump (including tank vent and all lines, new Racor filter, new secondary filter, priming bulb).

Priorities: new coil, clean carburetor - in that order.

[hanleyclifford]

Kelly - Welcome back, and don't forget the lowly condenser (see post # 10 this thread). Regards, Hanley Just noticed you are using the electronic ignition. Been a lot of talk here about these units and coils - try putting the old points etc back in, just to eliminate the electronic unit as the culprit.

[roadnsky]

Kelly-
Welcome back.

Which Electronic Ignition do you have?
Which Coil?
(Yes, that's where I'm going...)

[Kelly]

Jerry- I'm using the Ignitor unit from the Moyer catalog with a generic French coil measuring 3 ohms across the posts as per recommendations found here (installed in 2007).

[roadnsky]

Originally Posted by Kelly

Jerry- I'm using the Ignitor unit from the Moyer catalog with a generic French coil measuring 3 ohms across the posts as per recommendations found here (installed in 2007).

Ok, couple more questions...
•How long ago did you go to the Electronic Ignition?
•Do you have a spare coil?
•If so, have you tried the swap-out exercise when you have the shutdown?

Maybe you see where I'm going here...
Many of us with the Ignitor, have also gone to the Pertronix epoxy-filled Flamethrower coil.
They seem to like working together.

I think if you can figure an inexpensive way to do the coil swap-out, you can eliminate that as a possible issue.

One other place to start looking.
Rigs would suggest that you check the ignition circuit for a possible "cold solder joint."
Give this thread a look-see...
http://www.moyermarine.com/forums/sh...older#post9346

[Kelly]

Thanks for directing me to that thread.

For about 3 years, the tach on previous boat would flicker after running a while. Then it would occasionally flicker and the engine would shut off, but infrequently. I could always restart the engine in about 20 minutes.

This echoes pretty closely my symptoms, but I don't know what the "slave starter solenoid" is as mentioned by rigspelt. I think the main lesson to be learned here is to inspect/clean all connections in this circuit and have the spare coil handy for swapping if the problem still occurs.

So, for the questions:

• also in 2007
• I need to find my old coil or buy a new one
• haven't swapped yet...

[roadnsky]

Originally Posted by Kelly

Thanks for directing me to that thread.

This echoes pretty closely my symptoms, but I don't know what the "slave starter solenoid" is as mentioned by rigspelt. I think the main lesson to be learned here is to inspect/clean all connections in this circuit and have the spare coil handy for swapping if the problem still occurs.

Kelly-
I think what Rigs referred to was that his cold connection issue was at his starter solenoid.
If he catches this thread, I'm sure he'll clarify his thinking.

Ok, while you look for the spare coil to do the swap test, maybe you can check and/or eliminate any issue with the ignition circuit having a bad or cold" connection.
Here are Don's instructions...

To keep things simple, before chasing the entire primary circuit which runs from the large battery terminal on the starter solenoid, through the ignition switch and back to the positive terminal of the coil, you could simply connect a jumper wire from the large battery terminal on the starter solenoid to the positive terminal of the coil. If the engine never shuts down as long as that jumper wire is installed, you will have confirmed that the primary ignition circuit is a cold joint in it someplace.

If the shutdowns continue with the jumper wire installed, you can check the remaining short section of the primary circuit which is between the negative terminal of the coil and the points. Sometimes the conductor in this short wire develops a cold joint where is passes under the distributor cap or at the terminal of the coil or at the points themselves.

Maybe give that a go?

IMPORTANT NOTE: Installing the jumper wire between the starter solenoid and the coil is the very same thing as turning on the ignition switch, so you cannot leave that wire installed except when running the engine or you will burn out the coil, your EI and/or kill the batteries.

[Dave Neptune]

Kelly are you or did you check for spark when she died and would not start?? Important!!! This will let you know if it is ignition related!!
Your fuel system sounds as if it should be OK, although I didn't like that it took 4 minutes to get fuel to the carb.

If you can look down the throat of the carb while running do so. If you see fuel puddling in the throat it could be flooding the engine and it won't restart until the fuel has disapoated from the cylinders.

Dave Neptune

[67c&ccorv]

Kelly,

1.) What kind of polishing filter are you using? You say it is clear and you can see the fuel flowing through it - the one Moyer sells is a steel unit that you can not see through. I am wondering whether the flow rate of your filter is correct and if it may be clogged?

2.) Don't think the aluminum fuel tank will stand up well to the new ethanol fuel formulas we are getting at the pumps now.

[Mo]

Kelly,
I went through the same thing this past weekend and thought it was electrical. Changed plugs, coil, points, rotor, cap and condensor... at sea. It felt light she was missing and I wondered if I had hit the prop it rattled so much. Putting my spare electrical components on didn't do a thing for her.

Then I went at the fuel...changed out filter/separater and it did have a bunch of dirt and discoloration...and all was changed 3 months ago...I did it again with my spares...ran for a bit then 20 minutes later started to miss and sputter...then pick it up and be fine on and off.

Pulled carb, cleaned, changed filters again...now running fine. I was leaning towards a fuel pump until it started to run better. There are a few other things that can cause your problem also and they have been touched upon. I went through 2 sets of fuel filters before it sorted out.

902 461 1228 if you need to talk about this...I just got in a few hours ago and happened to be online here to see if anyone else had the same problem.

Good Luck.