Adjusting Timing Belt on 1986 Volvo Penta AQ151A

[ijarvie]

Can anyone out there advise me as to how to check that the timing belt on my Volvo Penta AQ151A has not slip a notch or two? I am concerned that the timing between the camshaft and the crankshaft may be out slightly and want to check that they are in synch. I was told by a marine mechanic that the rubber belt could slip a notch if the engine has backfired. The reason I need to check is that I have to turn the distributor all the way one direction just to get it to 6 degrees BTDC. Yesterday, I installed an electronic conversion kit to replace the old points system. I have a nice spark at all the cylinders and there is plenty of gas coming out of the carbs, but the engine won't start now. With the distributor completely turned one direction, the same as I had it with the old points, the engine barely makes an effort to try and start (and I mean barely). When I pulled out the plugs to have a look at them, they are wet and do not show that they are burning any fuel. But with the spark plug out (still attached to the high tension lead) and grounded, I get a nice spark, between the gap, when I turn the engine over. Any suggestions?

 

[bruceb58]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

Did you pull the distributor to put the conversion kit on? If so, you may have put the distributor in 180? out and the distributor is firing on the exhaust stroke.

You can check the timing of the timing belt easy enough. Its in the service manual. If the engine was running fine before your distributor modification, not sure why you would think its slipped now. And by the way, if the belt is properly tensioned, they rarely if ever slip.

 

[ijarvie]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

Did you pull the distributor to put the conversion kit on? If so, you may have put the distributor in 180? out and the distributor is firing on the exhaust stroke.

You can check the timing of the timing belt easy enough. Its in the service manual. If the engine was running fine before your distributor modification, not sure why you would think its slipped now. And by the way, if the belt is properly tensioned, they rarely if ever slip.

Thanks for your reply. No I did not take out the distributor. The engine was hard starting, sometimes backfiring when I tried to start it before installing the conversion kit. It had to turn over many times before it started. Once it started, it ran fine and seem to idle smoothly enough at 850rpm. The engine would start better when it was cold but was very hard starting when it was hot. I had set the timing at 6 degrees TDC. After installing the electronic conversion kit, it will not start. It comes close to trying to start, but just doesn't get there. It also backfires quite a bit while trying to start, especially when fully choked, (with the idle throttle lever fully pushed down). I am not sure if it has any relevance, but when I am cranking the engine over, and use the timing light, it shows the timing mark at about 10 degrees after TDC. I am assuming this is not useful as the engine is not cranking at 850 rpms? One thing I have noticed is that there is a pool of gas at the bottom of the carburators. I can see this by opening the butterfly values and looking down the throat of each carburator. Is this normal?

 

[ToemanDoug]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

Have you considered the possibility that the electronic ignition pick-up module is oriented just differently enough that you need to remove the distributor and re-install one tooth offset from where it is now?

 

[bruceb58]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

10? ATDC is way off.

Personally, I would stick with your points.

 

[ijarvie]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

Have you considered the possibility that the electronic ignition pick-up module is oriented just differently enough that you need to remove the distributor and re-install one tooth offset from where it is now?

No I hadn't thought of that. I will check on this. Thanks

 

[ijarvie]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

No I hadn't thought of that. I will check on this. Thanks

I pulled the distributor and adjusted it so that the timing marks got close to 6 degrees TDC. I got the engine to start right away (for about a second or two) but then it shuts down.... as if the key is turned off. Not sure why this is but assume it may have something to do with the electronic conversion kit I installed. I am just now making sure all the connections are secure.

 

[ijarvie]

Re: Adjusting Timing Belt on 1986 Volvo Penta AQ151A

I pulled the distributor and adjusted it so that the timing marks got close to 6 degrees TDC. I got the engine to start right away (for about a second or two) but then it shuts down.... as if the key is turned off. Not sure why this is but assume it may have something to do with the electronic conversion kit I installed. I am just now making sure all the connections are secure.

Update.... victory! I thought that the red wire from the ignitor (electronic points) had to be connected directly to the coil as per the directions in the box. In doing this, the ignitor does not have a constant 12 volts. It did have the 12 volts though when I turned the key all the way to engage the starter motor because of the wire coming from the solenoid to the positive side of the coil. Once the key was released, there was no longer any power to the ignitor. I then connected the red wire from the ignitor to the opposite side of the ignition switch so it would have a constant 12 volts once I released the key but would not have any power when the key was shut off. This worked and the engine now starts instantly, idles nicely and has very nice throttle acceleration.... much to my relief.

Thanks for your input!