AQ131 Ignition Coil Troubles?

Kenepela

Seaman Apprentice
Joined
Jul 19, 2009
Messages
31
I have a Volvo AQ131D motor and want to see if I need to replace my ignition coil and wanted to do an ignition coil resistance check but do not know what the resistance values should be for the primary coil check and the secondary coil check. Any help? I am wanting to check because the other day when i took boat out it was idling fine and when i started to run, it would loose power and the motor would die out (as if running out of fuel). I know it is an ignition issue and not a fuel issue. in the drive way it idles fine and throttles up fine, but there is no load on the motor. I checked my dwell and was right a 62 degrees, I happened to put on the timing light and the flash was either erratic, double flash or no flash. I hooked timing light to my car and it worked perfect. Back on the boat, same thing, erratic flash pattern if any. New plugs, cap, rotor and condenser a few months ago and motor was running fine. If i do need to replace coil can i use an automotive one or should it be a marine coil? Any suggestions or help would be appreciated before i randomly throw more money into it hoping to fix the problem (the Lord and my wife knows i've done enough of that already) Thanks and Aloha!
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
71,095
Re: AQ131 Ignition Coil Troubles?

(as if running out of fuel).

Ayuh,.... What makes ya so sure it's an ignition issue,..??

Did ya Check the fuel filters,..??

How it runs in the driveway, without load is irrelevant...
'n I don't know what's a matter with yer timing light...
If the motor was missin' spark like you say, it'd be skippin' right outa the boat...
Generally speakin',... coils either work,.... or they Don't....
 

dennis461

Chief Petty Officer
Joined
Aug 11, 2011
Messages
516
Re: AQ131 Ignition Coil Troubles?

Sounds like a loose connection.
If your capacitor is mounted on the outside of the distributor, make sure it does not have a screw loose (pun intended.)
Then look inside, the wire may be clipped on outside or run inside to a screw.
 

Kenepela

Seaman Apprentice
Joined
Jul 19, 2009
Messages
31
Re: AQ131 Ignition Coil Troubles?

Thanks for the quick replies, but i know it's not a fuel issue, new fuel tank, new filter, rebuilt carb. I know my timing light is good and that is why i know it's an ignition problem. I did not know if a coil would put out a weak spark, a spark strong enough to idle but not strong enough to burn the entire fuel being delivered at open throttle. I will check the capacitor, it is one that's mounted on the outside. I did pull off the distributor cap yesterday to look at it and the rotor and points and all looked ok. I did also look at the wiring on the inside from the capacitor and it looked fine. I didn't check if the capacitor was loose, it is not in a user friendly position on the distributor. I will check. Thanks
 

Mullin

Petty Officer 1st Class
Joined
May 12, 2011
Messages
256
Re: AQ131 Ignition Coil Troubles?

You can check the coil a couple of ways;
1. look at the spark, blue/white is good and strong yellow/red is weak and needs to be replaced. You can just hold the end of a plug wire a .25" away from the head, use something insulted to hold the wire though.

2. check the coils resistance with an ohm meter. it should read at least 3 ohms between the + and - terms, and over 7000 or more between either terminal and the main center high output terminal.

3. Just swap one in, they are really cheap. I used a generic GM coil with with the correct stats and it was $15. Don't use a MSD or Accel coil just because they are a low resistance coil and won't be compatible with a petronix kit if you go that way in the future.

From what I have seen, coils either work or they don't, unless they are one of these old oil filled type coils and then they will work until they get hot and then stop working.

However, first thought when I heard your problem was that it is probably the accelerator pump adjustment that seems to get everybody that has one of these solex carbs, me included. Does it die just when you hit the throttle? Can you kinda feather it up to higher rpms?
Also, I didn't see new wires in your tune up list, check those.
 

Kenepela

Seaman Apprentice
Joined
Jul 19, 2009
Messages
31
Re: AQ131 Ignition Coil Troubles?

Sorry took so long to reply but it was the fuel pump (and this was a new fuel pump I replaced about a year ago with very little hours on it). For some reason, something was sticking inside the fuel pump. I ordered a new fuel pump and while waiting for it I put in an electric pump in before the mechanical pump and boat ran good. When new fuel pump came in, I took out the electric pump and just tried it with the same mechanical pump and it has been working fine ever since, so i have a new fuel pump for a back up now. Thanks again everyone.
 

KGPIN

Cadet
Joined
May 15, 2012
Messages
22
Re: AQ131 Ignition Coil Troubles?

Mullin

Can you give me some additional insite as to some similar problems im having with an AQ 131A. Its a 1987 and I just got this boat basically for free. I have rebuilt the carb., replaced the wires, checked the coil (2.0 ohms) with external resistor installed. I installed an electric fuel pump since I already had one. I am awaiting new points, rotor and capacitor arrival. The motor runs and idles fine, but bogs under quick acceleration. I can feather it up to higher RPMs like you indicated in this thread which caught my attention. Well here are my questions:

Want to replace coil since it is original. If I replace it with a 3 ohm unit such as a hotspark do I remove the resistor which is in line connected to the alternator? I think this is the resistor they refrence in the schematics.

I cannot find any capacitor installed on the distributor, but I know all engines with mechanical points require it usually. I dont know the history of this engine so I dont know if it was removed. Do you know if they were located anywhere else on these engineor not at all?
I plan on installing once recieved. Once I get new ignition parts installed I plan on resetting the timing and retesting to see if that was it.

Do you have a reference with regards to adjustment of the accelrator pump on the Carb? The only other adjustment I see is the idle mixture screw.

Any input would be appreciated.
regards
Paul
 

Mullin

Petty Officer 1st Class
Joined
May 12, 2011
Messages
256
Re: AQ131 Ignition Coil Troubles?

Mullin

1. Want to replace coil since it is original. If I replace it with a 3 ohm unit such as a hotspark do I remove the resistor which is in line connected to the alternator? I think this is the resistor they refrence in the schematics.

2. I cannot find any capacitor installed on the distributor, but I know all engines with mechanical points require it usually. I dont know the history of this engine so I dont know if it was removed. Do you know if they were located anywhere else on these engineor not at all?
I plan on installing once recieved. Once I get new ignition parts installed I plan on resetting the timing and retesting to see if that was it.

3. Do you have a reference with regards to adjustment of the accelrator pump on the Carb? The only other adjustment I see is the idle mixture screw.

1. The ignition system needs to have a certain amount of resistance. Either use an internal resistor coil by itself or an external resistor with a coil with low resistance. You can check it with a ohm meter to be sure.

2. There should be a short wire coming from the points inside the distributor that plugs directly into the capacitor. The capacitor is usually mounted on the side of the distributor with a spade connector protruding into the distributor for the connection to the points.

3. The accelerator pump is finicky and a pain to get just right. There should be three adjustments on the carb; the idle screw, mixture screw, and accelerator pump nut. To get the motor to accelerate without bogging down or chugging or even dying sometimes, this is what worked for me:

First, I adjusted the accelerator pump in my driveway on muffs, but you could do it on the water too. Get the motor up to running temp before any adjustments. The acc. pump has a threaded rod with a nut on the end. The position of the nut will make the pump squirt its gas sooner or later. Take off the flame arrestor, disconnect the throttle linkage at the carb.
Now hit the throttle (the bracket on the carb itself) while keeping an eye on the squirt of gas that will be shooting out of the 'candy cane' into the throat of the carb. The squirt should come near instantly when you hit the gas. Backing off the screw will make it engage faster and faster. There is a point where it is too far though. The motor should be able to be punched, get that squirt of gas, and it revs up with nearly no lag.

Okay, second thing to get it running real nice is to set your idle on the water in gear. Put it in forward and adjust the idle screw to the proper rpms for your engine. Too low and it will bog when you accelerate, too high and you will be going way too fast when you try to dock.

Third is to set the mixture screw. I think this step is a bit more of an art form or a juggling act. Adjust it to see if it idles any smoother, but then also hit the throttle (in neutral) to see how the adjustment affects acceleration too. You may now need to reset the idle screw as the mixture screw can bump or lower your idle rpms.

So in short, get the accel pump shooting fast, set the idle, and then adjust the mixture to get the best performance. If you get it right, you shouldn't have any more stalls when punching it and can get a faster acceleration without the chugging. My boat still chugs it a little once in a while, but she is old and cold blooded.

PS. when you have the flame arrestor off, don't look staight down at the carb. One backfire and there go you eyebrows.:eek:
 
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