Volvo Penta AQ125B Bogging down at full throttle

[xsnoboard]

I am having an ongoing issue since I took the boat out this summer. When the boat has a load it will run "fine" up to about 2200-2500 rpms. If I try to push past it the engine slowly bogs down until i come back a bit on the throttle. I took apart the carb and cleaned the jets. Fresh fuel. Bought new plugs and gapped them to spec.

I bought a spark tester and at the recommended gap I am getting a spark (when it gets darker out I will verify that its a good spark and not a weak one) I then set the gap to just about a half inch or less to see the spark strength. It wasn't sparking at all. Not sure if it would or not at this distance?? If I close the gap a little more then it would spark once in awhile.

I also tested the resistance of the ignition coil. I believe the primary winding measured 3.2 ohms and the secondary winding measured 9.94 ohms.. I am not sure what the factory resistance should be in this particular ignition coil. If anyone knows that would be great! Or if someone could provide the manual that would have this information. I have a service manual but it doesn't have anything in it about the ignition coil specs.

If anyone else has any other ideas that would be greatly appreciated.

Thanks,

Cory

 

[Bondo]

Re: Volvo Penta AQ125B Bogging down at full throttle

Ayuh,.... Change the fuel filters, 'n inspect the contents of the take-offs..

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

The aftermarket in-line fuel filter looked pretty good but then again maybe I'm blind. Wouldn't hurt to replace it nor would it cost much. Plus, the plugs after a day use were black, assuming that its running too rich?

 

[Maclin]

Re: Volvo Penta AQ125B Bogging down at full throttle

The coil is only as good as the signals it gets from the distributor. When was the last time new points and condenser were installed, and the points dwell and timing checked/adjusted?

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

I have only checked things that could possibly go bad while sitting over the winter time. I wouldn't imagine that the timing would go out of whack when it was not running unless it slipped the first time I started it up (which I am sure is possible and something simple to check) I am going to check the timing next and I may just replace the ignition coil (Last owners said they had the same problem in the past and they had to replace the coil) I didn't replace the coil yet because I didn't want to just throw parts at it. I wish I knew what the resistance spec was of the coil. As far as the points and condenser I am not sure when they were last replaced.

Does anyone know if I can use an ignition coil of an equivalent automotive engine e.g 1985 Volvo 244 DL. Would be nice since I can get the coil from advanced auto for $25.

 

[Maclin]

Re: Volvo Penta AQ125B Bogging down at full throttle

As far as the points and condenser I am not sure when they were last replaced.

Just sayin', points control the dwell, dwell controls the amount of time the coil has to build the spark charge. Dwell out of tolerance lowers spark energy and limits rpm, some rev limiters work off of this principle. Checking it removes one variable. Wouldn't be the first time a set of points acted up after a layup.

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

Sounds good I will look into that. Not sure what to look for when looking if the points are good or not. When it comes to ignition I am clueless...

Does anyone know if the OEM Volvo Penta AQ125B's ignition coil is suppose to have an internal or external resistor? I pulled the ignition coil on my boat today and its a Bosch 0221119039(only number I could find on the part) The only thing I could find unofficially said it has an internal resistor. I followed a purple wire that was attached to the ignition coil and it lead to a white block (Assuming this is an external resistor? If that's the case what harm could this do having an ignition coil with an internal resistor also connected to an external resistor? (Maybe I should start a new post on this topic.)

The the white block with the purple wire the external resistor???

)

 

[NorthportTroller]

Re: Volvo Penta AQ125B Bogging down at full throttle

Yes, it is. I had to replace mine and kept a spare in the glove box.

I had issues with the new ethanol fuel jacking up my fuel system. Had to replace all the rubber fuel lines and clean the carb and it was fine after that.

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

You had to replace the external resistor or ignition coil?

 

[NorthportTroller]

Re: Volvo Penta AQ125B Bogging down at full throttle

You had to replace the external resistor or ignition coil?

I replaced both. It's been a few years so I don;t have the exact details and part numbers but I have been in your shoes before.

I also had to to pull that motor out to replace some seals and in between parts of the motor and drive. You know there is a grease fitting on the bell housing for a bearing in the drive? That was another hard lesson I had to learn. I think I still have the service book for that. I can see if I do and if you are interested we can make a small exchange. I am pretty sure it is in my garage. It's a pretty good book for that motor and out drive.

 

[Maclin]

Re: Volvo Penta AQ125B Bogging down at full throttle

If the external resistor is out no spark will happen, engine will not run. It may start but then as soon as the key is returned to Run from Start it will quit.

I know changing the coil seems like a good and easy thing to try, but the real deal for ignition is the points condition, setting and adjustment to get the dwell in tolerance, then get timing set, and good condition cap and rotor for distribution of the spark. Only then will the coil be able to shine.

I suggest you do a real tuneup of the igniton's electrical parts, or have one done for you, then see how it runs.

Over and out.

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

Unofficially, I think i solved my issue with a new ignition coil. My spark seems to be 10x stronger. I can increase the gap at least an inch with the ignition wire tester and I still get a spark before I could barely go 1/4 of an inch... Also I noticed the new ignition coil must have some sort of oil in it? I could hear it when I picked it up. I shook my old ignition coil and it sounded dry inside... maybe it leaked over the winter?

I will officially test it in the water when it gets nice out. (Rain all week) I will then report back if that fixed my problem.

Thanks

 

[Maclin]

Re: Volvo Penta AQ125B Bogging down at full throttle

The old coil should have had oil in it, acts as a heat dampener. Oil seeping out of the coil tower or at the seam between the can and the top is a sign the coil may be about to fail. Coils should be mounted straight up and down when possible because of this, especially in high heat locations. I was always confused when I saw engine or car/boat manufacturers mount them on their sides, that is just asking for the oil to run out sooner.

Learn about the rest of the system though, the dwell controls how much spark energy builds up in the coil before the spark. The timing of the spark that the dwell allowed to build up in the coil is another key factor.

Dwell is easy to check.
Timing is almost as easy to check also.

 

[xsnoboard]

Re: Volvo Penta AQ125B Bogging down at full throttle

Thanks I am going to check it all even if this fixed my issue. Could still have things out of whack... And yes my ignition coil is mounted sideways behind the engine... Maybe I will remount it vertical. Thanks for all the help

 

[jasonb87]

volvo penta aq130c boging down..

volvo penta aq130c boging down..

hello i have a 76 glastron trihull volvo penta 280 out drive enginge is a volvo penta aq130c duel carb solex 44's
first thing checked breaker point gap in disturber its at 18
new plugs and wires new starter new battery's
timing says middle is 37degrees so i set it there at 2000rpms whitch it also says to do
took it out and easily put it to open throttle and only goes to 2500rpm witch im only going 15mph
took both carb off cleaned them as well as the fuel filter because it has a glass housing re adjusted them to the engine sat at 750-850rpm took out and same problem but almost got it to 3000rpm..im stumped and need some answers if somebody out here has em. oh and also i tryed to time it at idle "850"rpms and set it at 13degrees still nothing so its back to where factory says..
ANYTHING?????

 

[xsnoboard]

Re: volvo penta aq130c boging down..

Re: volvo penta aq130c boging down..

Still having an issue. Seems to accelerate slower (maybe in my head) but overall having the same issue. Is it likely that the ignition coil isn't meant for that boat??? I got an ignition coil from advance auto for a 1985 Vovlo 244 DL. My boat is using the same plugs and wires as the engine in that car so assume that ignition coil might be similar. Looks exactly the same, if that means anything... I would like to note that I checked the spark with my ignition cable tester and set the gap to almost an inch and was getting a spark so I assume this is a strong spark if it can travel that gap. ( The other ignition coil couldn't do this)

Would gapping the spark plugs too close cause any issues? I am pretty sure I went to spec at .028.

I am not sure what to look for with the distributor so I took some pictures. See below.

I would like to check the timing but I do not have a timing light nor am I familiar with checking the timing.


Having an issue attaching the images for the distributor. Go here http://www.knasty.com/boat/

 

[Maclin]

Re: volvo penta aq130c boging down..

Re: volvo penta aq130c boging down..

Plug gap is in spec, so should not be a problem.

Turn the rotor, it should move smoothly with just a little resistance in one direction for a few degrees then snap back when released. That will check the mechanical advance which works as engine rpm's increase to advance the timing accordingly.

The advice in post #11 is still valid and "waiting"...

Points can get arc-welded shut when ignition is left on, then when engine is cranked pieces can get pulled off one contact or the other. They can also corrode just sitting if their surface has been compromised this way. Sanding/filing usually just gets the surfaces etched and makes it easier for them to arc and take pieces off each side.

I suggest you get a dwell meter and check the dwell, it can be checked without removing anything. I believe the AQ125 should be at 62 degrees +/- 3 degrees. Dwell is easy to check and is the tell-all regarding the current points setting. If dwell is off then rpm's are affected due to compromised spark building duration, also timing is affected.

Applicable thread here...:
http://forums.iboats.com/showthread.php?t=553776

 

[xsnoboard]

Re: volvo penta aq130c boging down..

Re: volvo penta aq130c boging down..

In regards to post #11 once I find the parts I will order them.

 

[xsnoboard]

Re: volvo penta aq130c boging down..

Re: volvo penta aq130c boging down..

Good news. I replaced the points. Reset the dwell and timing and sure enough I can hit 4000 rpms. I also bought a condenser but I didn't install it yet. Thanks again for all your help.

 

[Maclin]

Re: volvo penta aq130c boging down..

Re: volvo penta aq130c boging down..

Good deal.