AQ 125 timing problems?

[lutherfetch]

Well, I stepped in it bad. I bought an old Capri (85 i think) with a ACQ125a (if I remember correctly.) Last year, it was running like crap, and I decided I was going to clean it up before I put it away. I did not know the history of the boat and I wanted it to be reliable.

First, I rebuilt the carb when I bought it. That went well. Installed and ran. Still, had that nagging dead spot between 3000 and 3500 rpms. So, I ordered a junk carb off the internet and pulled the tower out of it. Tried filling and drilling holes, shortening the extra tower, and meddling with it. Dead spot was between 3000 and 3200 last time the boat ran right. Also, should tell you I live and boat at 7000 feet here in WY. Also switched out fuel pump, cap, rotor, plugs, wires, and oil change. Ran okay most of the summer like this. Should have left it alone. Oops.

Decided to change the timing belt, put in a Flamethrower coil and Pertronix electronic ignition. Should NOT have made all changes at same time. But, thats history now. I now have a boat that will not run. It has almost NO power. Tried switching back to orig coil and points. Doesnt want to run. It is backfiring to the point that I had a flame blowing out the carb. Not good. Pulled the covers off and dbl checked my timing marks. Dead on. Pulled the distributor and valve cover to make 100% sure I was on my comp stroke and at TDC and plug was firing at right time. Unless there is some secret handshake with Volvos that timing marks are only a "suggestion"... this engine is timed correctly. So, why is it backfiring, gutless, and giving me black plugs? Now, it is like this with both the orig coil and point and electronic ign and flamethrower. HAd to have someone tow me back to the dock. Makes no sense.

What am I missing?????? I am REALLY stumped. I have read that Volvos firing order on some engines have the #1 cylinder at front of eng, and some at the rear. Tried running plug wires both ways. When I pulled the valve cover, I am convinced that the #1 plug is at the front of the engine. Correct? I do not trust my Clymer manual from what I have read online.

Would LOVE to have a Volvo mechanic steer me in the right direction here. Gotta be something simple I am missing.

Thanks.
-john

 

[mcleaves]

Re: AQ 125 timing problems?

What manual are you using? When you say it won't start is is just cranking or is it sputtering and backfiring etc?

[EDIT] I see you did mention backfiring and a tow. Does that mean it ran but poorly? Talk to me more about what exactly is going on during running or attempting to run. I have been down this road with the 125 (including the upgrade to pertronix) and I have a pretty god idea what may be going on depending on what conditions you are experiencing.

 

[Don S]

Re: AQ 125 timing problems?

Mike can probably walk you through the timing belt installation better than anyone. He used to do it daily for practice, guess it was more fun than just tightening a hose clamp to cure a running problem.

Here is the OEM manual you can download, and, as I recall the Clymers manuals have the wrong firing order in them. It should be 1-3-4-2
http://www.4shared.com/file/89797330/b32e5bf9/AQ125145_AB_Service_Manual.html

 

[mcleaves]

Re: AQ 125 timing problems?

Mike can probably walk you through the timing belt installation better than anyone. He used to do it daily for practice, guess it was more fun than just tightening a hose clamp to cure a running problem.

Here is the OEM manual you can download, and, as I recall the Clymers manuals have the wrong firing order in them. It should be 1-3-4-2
http://www.4shared.com/file/89797330/b32e5bf9/AQ125145_AB_Service_Manual.html

Acutally Don I the Clymers has order right (pretty sure). It's the distributor rotation direction that is wrong. Or maybe it's the order is wrong in the Clymer's and the rotation is wrong in the Seloc. Yeah I still have fond memories of tearing that thing apart, over and over, and over.........

And now "I" have another fuel problem to solve. Sent you an email. Check your regular mail.

 

[Mischief Managed]

Re: AQ 125 timing problems?

It's been a really long time, but I recall that my AQ125 timing belt had the correct alignmnet marks for the crank, cam and intermediate shaft, but the engine rotation arrows on the belt had to point backwards to be set right. Maybe mine had a car timing belt or something. Sorry this post is vague, hope it helps.

 

[lutherfetch]

Re: AQ 125 timing problems?

I sat up till 4am reading everything I could find about this engine. I do have a few specific questions...

- Where does the ballast resistor live? Should be on + side of coil wire, right? Should I pull it to use the Pertronix coil and ign? Should I run a different plug with this setup? Help!

I wonder if I have cooked the plugs or not getting a good spark. That would certainly cause it. Do NOT see any damage to cap or rotor.

I did have the boat running and get it in the water. It took forever to start and needed starting fluid. It had just enough power to get it off the trailer and start moving under its own power. WOT did not produce enough speed to even troll with. Ran for all of two minutes before it left me sit. Backfired so hard it blew flames out the carb that sat and burned till I could throw a wet blanket on it.

I think that was my fault. I had hooked plug wires both ways with 1 being front and then 1 being back. Only would run with 1 being back. Go figure. So 2 and 3 were definately reversed. Think I was running on 2 cyls. I dont know why.

Went out and looked at timing marks again. I am 100000 percent sure the timing marks all line up. Put a screw driver in piston 1 to make sure it is TDC on comp stroke to time the dist cap.

OK... here is what I have gleaned from all my reading. May have bad plugs. Rebuilt an ATV engine over a bad spark plug before. It is one of the things I changed that went from my engine going from a runner to an anchor. Advance in the dist may not be working. That engine only has ever run at 20 deg BTDC. If I set it at 10, it will not run. Did use a dwell to set points. Gave up on it and set it to where it would run. Now I wonder if the advance is stuck. Engine does run hotter than hell and water boils out the heat exchanger. Thought it was a plugged heat exchanger or stuck thermostat. Pulled both. replaced thermostat and boiled exchanger in CLR. HAve no idea if that fixed it or not. Thinking now it is a symptom of the same problem and has nothing to do with exchanger. Will not know till I get it running right.

So... engine is currently at a point where it will fire and run for all of 5 to 10 secs right now. Going to swap plugs and start over with original coil. Its gotta be something simple I am missing. Convinced it is NOT the timing belt. I have tried every position imaginable with distributor. Can even hear the spark click when I position it. Cant be problem. Gotta be a weak spark or flooded engine from me messing with the carb. Will also put that back to stock.

Would LOVE to know whatever thoughts you might have (besides me being a moron for changing everything at once).

Thanks
John

 

[Don S]

Re: AQ 125 timing problems?

Did you ever set the timing with a timing light?

Put a screw driver in piston 1 to make sure it is TDC on comp stroke to time the dist cap.

How do you know it was on the compression stroke? You could be off one complete revolution of the engine.

 

[mcleaves]

Re: AQ 125 timing problems?

Did you ever set the timing with a timing light?


How do you know it was on the compression stroke? You could be off one complete revolution of the engine.

Agree +1

 

[lutherfetch]

Re: AQ 125 timing problems?

GD plugs had me searching for zebras again. Glad to hear you were all thinking timing too. Its the simple stuff that always hoses me. Was ready to pull the motor.

Switched the carb back to stock. Nothing. Changed to NGKs and it not only fired, but I did not even have to prime... just bump the key. Irritating! Second time I have dumped hours and days into diagnosing engine problems over a brand new $2 spark plug.

Anyway, got the Flamethrower and Pertronix ignition running. Eng timed at 10 deg at 900 rpms. It does run better at 15-20. Why??? I am at 7000 feet. Altitude matter? Anyway, have it set at 10 right now and will run tomorrow and see if that had anything to do with my overheating issues. I hit 12000 rpms and it really heats up and starts knocking hard. Why? I will say it currently sounds better than I have ever heard it run.

Anyway, thanks for the help. And, oh yeah, just kidding about the rpms. Just wondering if you were paying attention. Had to pitch down two props to get my rpms up to 5500. Have 3 props for different alts. Hopefully it will run cooler for me. Have considered pulling the exchanger alltogether and running lake water to cool it.

-john

 

[Don S]

Re: AQ 125 timing problems?

Let me guess, you had Champion plugs in it didn't you?

 

[lutherfetch]

Re: AQ 125 timing problems?

Autolite 63s... Wont touch Champions