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High speed ignition problem AQ131D

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rasky333

New member
Stock engine with points. Starts, and runs perfectly, until I go above about 3,000 RPM, then it starts having a serious miss. Acts like ignition to me. I unhooked the tachometer: send, and ignition leads, but miss still is present. It runs great below about the 3,000 mark. Idle is also perfect, and all throttle changes below 3,000, are good.
 
spark plugs old, dirty or wrong gap.
points old, dirty or wrong gap.
plug wire old dirty, cracked (look for sparks at nighttime)
loose wire on capacitor (on side of distributer)
 
dennis461 said:
spark plugs old, dirty or wrong gap.
points old, dirty or wrong gap.
plug wire old dirty, cracked (look for sparks at nighttime)
loose wire on capacitor (on side of distributer)
Click to expand...

WOW, what a response to my issue.

1. One hour into a outing, wot was perfect, but the problem started at about the two hour mark. It had been perfect before this outing.
2. Plugs, points, wires, are new, but I only timed it at idle (850 rpm). I'm not sure how to do the 4,500 timing, or the dwell.
3. I was told, by the Volvo Penta dealer, that a bad tachometer could cause the problem. That is why I disconnected it. It had been acting a little irregular prior to this matter.
4. Could a distributor advance mechanism go bad so quickly? Might it just be sticking, and need lubrication?
5. Could a bad coil, or condenser cause the problem?
6. Which of the aftermarket electronic ignition systems are good.
7. I wish I knew more about electronics.

Thanx: Jack
 
I'd start with the ignition distributor and the contact points.

How did you set the contacts points..... by setting the gap or by setting the dwell angle?
(point gap is an estimate only of correct dwell angle)

On a four cylinder engine you have 360* of distributor shaft rotation for all four cylinders to undergo one spark event each.
This means that you have 90* of distributor shaft rotation for a single spark event.
Of that 90*, a portion is dedicated to coil saturation.
This is the dwell angle.
The other portion of the 90* is when the contacts remain open.
See your OEM specs for the dwell angle, and use a dwell meter.

Do you see any excessive shaft wobble?
Shaft wobble may cause an erratic dwell angle.

Have you checked the progressive advance?
If the progressive is limited, it may be causing your issue.

If all is OK, I'd then look towards fuel delivery.


.
 
Jack ...................

rasky333 said:
1. One hour into a outing, wot was perfect, but the problem started at about the two hour mark. It had been perfect before this outing.
A bad ignition coil may act up when it warms up. Perhaps replace the coil.

2. Plugs, points, wires, are new, but I only timed it at idle (850 rpm). I'm not sure how to do the 4,500 timing,
You will increase RPM as you continue to strobe the timing marks.
Write down the advance numbers at varying RPM info in graph form.
(see my example below)
or the dwell.
A dwell meter is required for this.

3. I was told, by the Volvo Penta dealer, that a bad tachometer could cause the problem. That is why I disconnected it. It had been acting a little irregular prior to this matter.
Good call!

4. Could a distributor advance mechanism go bad so quickly?
Unless one of the flyweights or flyweight return springs was rusty and finally failed, it generally takes years or rust/corrosion for one to go bad.

Might it just be sticking, and need lubrication?
Yes, that is a posibility.
If a flyweight was sticking and was not returning to the BASE advance position, the progressive and TA will be incorrect.
IOW, while you were adjusting for BASE advance, the system may not have fully returned, therefor the advance from what you only THOUGHT was BASE, will be wrong.

5. Could a bad coil, or condenser cause the problem?
see #1.

6. Which of the aftermarket electronic ignition systems are good.
If you're talking about a retro fit kit....... none of them are. :mad:
The Hot Spark, Pertronix, and the likes are all Hall Effect.
Keep in mind that the kits do ZERO to correct any shaft wobble or wear to the advancing system within the existing distributor.

However, this is your only option unless you are willing to spend around $650- $700 or so.

I'd suggest staying with the contact point system and keep up on the maintenance.
Click to expand...
 

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re:" 1. One hour into a outing, wot was perfect, but the problem started at abot the two hour mark. It had been perfect before this outing."

One could read this as you were running @ WOT for 2 hours... I hope not ( for your wallet's sake). Marine engine life @ WOT is measured in 10s of hours, @ 80% of WOT it rises to about 1000 hrs, @75% rises to 1500 to 2000+ hours (especially w/"fresh" water cooling). While the I4 Volvos seem to be a bit more tolerant of WOT operation, you are still looking at very low 100s of hours of engine life. I got this information in a conversation with a design engineer with a USA marine engine manufacturer as well as from some insider data from Curtiss Wright corp while they were testing Wankle engine life vs. conventional engines.
 
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Bob, I understood his comment to mean that the engine was capable of making WOT RPM.
I too hope that he wasn't running at WOT for any length of time.
 
I am very easy on my equipment. I always cruise around 3,500 RPM, and only go to 4,500 for a few seconds at a time, just to check things out. My boat is a: 16' GW Invader, that planes out very easily. The engine is working perfectly, in every way, until I go above about 3,000, when it starts to cut out. Thanx: Jack
 
I took a look at the coil. It is a generic one with only numbers 1305, and 030112, on it to identify it. A note saying no external resistor required. I think the connections were wrong, with the distributor wire going to the + terminal. Should the ignition switch wire go to + ? It had just the tachometer wire attached to the - terminal. I also found moisture inside the distributor cap. Could these have something to do with my problem?
The fuel pump looks like the original, but I did not put a pressure tester on it to determine its output.
 
......................

rasky333 said:
I took a look at the coil. It is a generic one with only numbers 1305, and 030112, on it to identify it. A note saying no external resistor required. I think the connections were wrong, with the distributor wire going to the + terminal. Should the ignition switch wire go to + ?
Yes, that is correct. We wamt power to the + side.

Ballast resisted power for coils that require external resistance.
Non-resisted power for coilss that do not require external resistance.

It had just the tachometer wire attached to the - terminal.
The - side is the triggering side.
The tachometer also picks up it's pulse signal from the - side.

I also found moisture inside the distributor cap. Could these have something to do with my problem?
Yes, it may!
WD-40 is good for displacing moisture.

Click to expand...
 
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Moisture inside cap, especially in a salt water environment, is often accompanied by green crud corrosion on the contacts inside the "dizzy". A short term fix is to mechanically clean the contacts ( in addition to removing the moisture). Long term... new cap.
 
rasky333 said:
WOW, what a response to my issue.

1. One hour into a outing, wot was perfect, but the problem started at about the two hour mark. It had been perfect before this outing.
2. Plugs, points, wires, are new, but I only timed it at idle (850 rpm). I'm not sure how to do the 4,500 timing, or the dwell.
3. I was told, by the Volvo Penta dealer, that a bad tachometer could cause the problem. That is why I disconnected it. It had been acting a little irregular prior to this matter.
4


Thanx: Jack
Click to expand...

. Could a distributor advance mechanism go bad so quickly? Might it just be sticking, and need lubrication?
Yes, one winter layup with condensation could rust something
5. Could a bad coil, or condenser cause the problem?
battery to + ; distributor wire to - of coil
6. Which of the aftermarket electronic ignition systems are good.
don't do it
7. I wish I knew more about electronics.
Be careful what you wish for

From standing start, does it launch quick, pulling hard up to 3000 rpm then give you trouble?
 
An outside possibility... Did you clean and lube the cam on the dizzy when you installed new points? I stupidly forgot to do this once and the fiber piece on the points that rode the cam wore and screwed up the dwell... Another set of points in just a few hours of engine operation.
 
Use the P of E (process of elimination).

Fix/repair/test only one item at a time before going to the next suspect.

Once you have the ignition system fully functioning and off of your list, move to a fuel related possibility.
This means correct dwell angle, no shaft wobble, good hot spark, coil working when warm, correct progresssive advance, and the correct total advance.

Or.... do the reverse of this.

Just don't tackle more than one item at a time.

When the P of E is used methodically and systematically, it will not let you down!
Plus, when you do eventually find the problem, you'll be better equipped in the future.

Whereas if we just start throwing parts at a problem, we eventually fix the problem, but we end up not knowing what was actually wrong in the first place.


.
 
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Hi guys:

I found the problem, but what a big surprise. The arm, on the bottom of the body of the distributor, that allows the rotation to be adjusted for timing/dwell, had broken off. It is a casting, and someone must have really reefed down on it, to cause the fracture. It looked ok from above, but when I removed the adjusting bolt, the piece came off. It was allowing the distributor to move, and change the timing. In the past I have serviced distributors that had a sheet steel adjusting plate, that would never break. I doubt if there is any way to repair the part. If all these Bosch units are cast, perhaps they need to be checked.

Thanx again for all the help.

Cheers: Jack Hillyer, Seattle, WA
 
Hi kimcrwbr1: I am interested, but I live a fair distance away. Could you possibly send some pictures to: 206 313 1270. Cheers: Jack Hillyer
 
kimcrwbr1 said:
Jack I live in maple valley and have a sterling bowrider with the AQ131D and the SP drive that was given to me. The drive and prop are in excellent condition but the motor needs a head and exhaust manifold. You can have the boat and trailer if you pay for the title transfer for both. The trailer is also in excellent shape. The sterling is basically a bayliner as the brothers split up. They are both 1991 if you want the distributor you need to take everything. PM me if interested I was going to fix it up but lost interest quite frankly.
Click to expand...

Put the engine at top dead center #1 piston,
pull dist
take loose part and dist to friendly neighborhood welder.
 
dennis461 said:
Put the engine at top dead center #1 piston,
pull dist
take loose part and dist to friendly neighborhood welder.
Click to expand...

If the crankshaft is not rotated while this is being done, you'll be OK.
However, I'd suggest using #1 TDC during the compression stroke only.

This way you'll be able to swing the distributor housing (ignition ON) for an initial #1 cylinder spark event check.
Once you see a #1 spark event (while @ #1 TDC C/S), you can check to see if you have the correct adjustment range for setting BASE advance.


Once BASE advance has been set, be sure to look at the progressive and TA.
BASE is BASE all day long.
We fire up on BASE, and we idle on BASE...... but the more important aspect of ignition advance is the progressive and TA.





.
 
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Rick...aka Ricardo: What does the C/S mean in: (while @ #1 TDC C/S). I have never heard "BASE", or "TA", in discussions of ignition timing. What do they mean. I have always just used: dwell, idle 6 degrees BTDC, and progressive advance, to set everything up. It has always worked for me.

Dennis461: I took the distributor + broken piece to a "expert" welder. He tried, but was unable to weld the parts together.

kimcrwbr1: I do not know how to edit my forum entries. If the pictures look ok, could I come down to see it this Sunday?

Thanx again guys: JH
 
..................

rasky333 said:
Rick...aka Ricardo: What does the C/S mean in: (while @ #1 TDC C/S).
We always look at ignition timing as though doing so for #1 cylinder. Although in truth, we could time an engine using any cylinder as long as the markings are there and are correct for that particular cylinder.
# 1 cylinder is always the forward most cylinder, so it just makes sense that we'd use #1.
All indexing is typically done while using #1 cylinder...... camshaft indexing, distributor indexing, etc.

No matter which cylinder we would use, the spark timing is based on where the piston is in it's stroke.
TDC comes around twice for every full engine cycle of a 4 cycle engine (compression/power/exhaust/intake).
We want to time for the spark event while the piston is just prior to TDC, but it must be on the Compression Stroke (C/S) or we won't be able to start it up.

I have never heard "BASE", or "TA", in discussions of ignition timing. What do they mean.
BASE advance is what the engine fires up on and idles on, and is always minus any progressive or total advance, whether it's via mechanical or EST (electronic spark timing).
It is a result of where the distributor housing is positioned when the spark event occurs at an RPM below any mechanical advance.
IOW, BASE or Initial advance occurs before an RPM that begins the distributor's mechanical advancing.
Once above idle RPM, the progressive advance begins.

Progressive advance = the degree of spark lead above BASE advance as RPM is increased.
This is a gradual increase in advance (in crankshaft degrees) per RPM until the progressive reaches it's limit.
The limit RPM is refered to as the "full in" RPM.

TA = total advance.
TA indicates the spark lead (in crankshaft degrees) while the advance has reached it's limit, but it must always be associated with an RPM, just as each stage of the progressive spark lead (in crankshaft degrees) must be associated with an RPM.
Progressive or TA numbers without an associated RPM are meaningless.

I have always just used: dwell, idle 6 degrees BTDC, and progressive advance, to set everything up. It has always worked for me.
As the mechanical advancing system becomes old, rusty, corroded, etc, it may not be doing what it's suppose to be doing.
Weak flyweight return springs compromise the advance.
This is why we do a dynamic advance test as to verify.

IOW, if we just set BASE and walk away, we haven't verified the progressive or TA.

If not enough advance....., we leave performance on the table.
If too much advance, and if too early....., we risk ignition induced Detonation damage.

This is why the OEM will always provide these specs for us, either in text or in graph form.
Click to expand...
 
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Hi Guys:
I solved the ignition problem. It was a faulty distributor. Running perfectly now.
FYI: I rebuilt my carb, and found out that I have the later model of the 44PAI. I was sold a kit for the earlier model, but many of the parts did not fit. Mike's, in Washington was the seller. Much cheaper on eBay, for exactly the same kit.
My only complaint with the Volvo Penta AQ131D is the noise. I thought I/Os were quiet. I sound insulated the engine cover, but not much difference. Any ideas?
Cheers: Jack, Seattle
 
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