Volvo AQ 125 A

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central2003

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I recently purchased a 1982 Bayliner with a Volvo AQ 125 A Motor. The boat was winterized before it was put away 2 years ago, but we are having trouble getting it to start. The starter will turn over fine, it is getting enough fuel, and it has plenty of spark. The only thing we can think of is that the timing is off. Does anyone have any helpful advice. I have already replaced the plugs, wires, new Dist Cap(expensive). I am only a beginner wrench turner so any easy solutions would be great. Thanks!
 
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central2003

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Re: Volvo AQ 125 A

The one other thing I didn't mention is that it will backfire every once in a while, and that is why we think it is the timing, or the firing order that is off.
 
Dunaruna

Dunaruna

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Re: Volvo AQ 125 A

Hi central, welcome to iboats!!<br /><br />Firing order is 1342. <br /><br />Another thing to check is the cam timing, need to check the timing belt.
 
mcleaves

mcleaves

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Re: Volvo AQ 125 A

Those belts jump teeth pretty easy so get the belt lined up.<br /><br />Also, get some new points in there as well and then set the dwell EXACTLY. I forget the numbers. These engines are REALLY fickle with dwell and timing. Doesn't take much to have it be off..<br /><br />Once you get it running it's a bullet proof engine<br /><br />M
 
mcleaves

mcleaves

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Re: Volvo AQ 125 A

Another post reminded me of this... Make sure your rotation direction is correct on the firing order. The aftermarket manuals have it wrong in places.<br /><br />Just in case you are using one of those.. Don't ask me how I know :).
 
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central2003

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Re: Volvo AQ 125 A

Does anyone know of a webpage that has a diagram or some help on how to get to the timing belt on this engine? I am having trouble getting to the belt to check and see if it is off. Any help would be great. I am more and more stumped on this engine.
 
Don S

Don S

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Re: Volvo AQ 125 A

There is no "Web Page" to explain the belt or how to replace it. But the Volvo service manual does a great job. It's Volvo Part Number is 7739856. Check with your local Volvo dealer or favorite Volvo online source.
 
bruceb58

bruceb58

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Re: Volvo AQ 125 A

I doubt your timing belt slipped a tooth but I guess anything is possible. <br /><br />Firing order is 1342 for clockwise rotating motors.<br /><br />Go to this page that shows the timing belt replacement of a B21 automotive Volvo engine:<br /><br /> http://www.volvoclubofbc.com/technical/tech2005photos.html <br /><br />There are three things you need to line up, the camsaft pulley has a notch that lines up with a notch in the valve cover, the crankshaft keyway lines up with a notch on the block and the pulley which drives the distributor gear also has marks that will line up.<br /><br /> http://www.volvoclubofbc.com/technical/techpics/2005/ts/DSCF0049.JPG <br /><br /><br /> http://www.volvoclubofbc.com/technical/techpics/2005/ts/DSCF0059.JPG <br /><br />I really doubt the timing belt has slipped here. It is very rare. I would replace the belt if the age of it is unknown. At one time these engine were not interference engines but that was in the late 70's. Keep that in mind when rotating the engine/camshaft with a timing belt removed so that you don't bend a valve. Best thing to do would be to get everything TDC and change it in that position.<br /><br />Go buy a manual. Money well spent!
 
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Bsturkie

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Re: Volvo AQ 125 A

Central,<br /><br />Did you pull the entire distributer when changing the cap? If so, chances are that you didnt line it up right when you reinstalled it. I did the same thing with AQ125b and got nothing but backfire. If so, it must be removed and reinstalled properly.
 
mcleaves

mcleaves

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Re: Volvo AQ 125 A

Originally posted by bruceb58:<br /> I really doubt the timing belt has slipped here. It is very rare.
Click to expand...
Actually on these engines it's pretty common. especially if the pulleys aren't kept clean. The tensioner doesn't do the best job in my opinion. Also if you try to crank the engine by hand and rotate the wrong way just a few lbs of pressure will slip teeth. A little desieling could do it. Between two of these motors I have owned I probably put the belt on and took it off 30 times (no comments from the peanut gallery Don!!)<br /><br />Also, you can break a belt at full speed on that engine and not a damn thing will happen. Nothing will come in contact.<br /><br />Now it may NOT be a slipped belt, but I would not say it's rare, at least not when talking about these Volvo 4's<br /><br />
Originally posted by bruceb58:<br />Go buy a manual. Money well spent!
Click to expand...
Agreed!!<br /><br /><br />M
 
bruceb58

bruceb58

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Re: Volvo AQ 125 A

I have worked on a lot of these exact engines in automobiles and never saw a timing belt slip. On the other hand, not often that someone trys to rotate them backwards so it's worthwhile checking.<br /><br />It's not very hard to verify that the timing belt is in the correct position. Just check the cam pulley and the crank pulley to see if they match up. This will be shown in the manual. The pulley that drives the distributor is not as critical becuase if that one is messed up, you can correct by pulling the distributor out and dropping it in the right spot. <br /><br />Also remember that the engine at TDC could be at the top of the compression stroke or exhaust stroke. Make sure it is at the top of the compression stroke with both valves of cylinder 1 closed when setting the distributor location. The timing will appear to be correct but you are actually a whole revolution off.<br /><br />You don't have to have the engine running to set the timing with your timing light. Just have someone crank the engine while you inspect the timing. That will get youin the ballpark timing wise.
 
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Spike3

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Re: Volvo AQ 125 A

aI have an AQ125B in a 18' Sunbird that jumped valve timing, and the pistons don't hit the valves. Anyone know where is the cheapest place to get a manual? Or does anyone have a used one for sale? The OEM manual P/N is 7739856<br />Thanks much,<br />wme222@hotmail.com
 
Don S

Don S

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Re: Volvo AQ 125 A

Start a new thread Spike.<br />You will get a lot more replies that way.
 
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tiki-dan

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Re: Volvo AQ 125 A

I have that same engine and am experiencing the same or similar problems. My seawater strainer started to leak and rusted the timing belt pulley which caused the belt to slip. I took it to the mechanic and $750.00 later I got it back it purred like a kitten. Unforunately it didn't get out to the water due to five hurricanes and my truck broke down. Now that I can get it to the water it won't start again. I was starting it every week with the muffs and running it for about 20 min or so but I missed two weeks due to 'hurricanes' and it hasn't started since. I have found some new ideas reading this thread and hope that the belt hasn't slipped...again..I was going to use some "Sea Foam" to free up the vales and loosen some of the carb. gunk. I'll let you know if that makes a difference.
 
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Eodbaer

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Re: Volvo AQ 125 A

This may seem stupid but did you new fuel in it. Two year old fuel will not burn well.
 
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DHPMARINE

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Re: Volvo AQ 125 A

I'd check the rotor.Had one once that seemed to have a 'resistor' in it.

DHP
 
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