VP-AQ125B valve timing problem

[Spike3]

Hey Guys, I recently acquired an '85, 18" Sunbird with an AQ125B Volvo Penta engine. I don't think it's been used very much at all but, it wouldn't run. I found that it had jumped valve timing. I understand there is supposed to be a sticker on the valve cover to set the cam timing? I couldn't find anything like that. putting the cam sprocket mark at 12:00 with the #1 cylinder at TDC The engine ran fair with the gunked up carb but, the timing may not be correct. How can I set the valve timing accuritly without that mark on the valve cover? I did put on a new belt. Any suggestions would be greatly appreciated, Thanks much.

 

[DHPMARINE]

Re: VP-AQ125B valve timing problem

A new belt won't work until you align the crank,cam,and jackshaft that turns your distributor.Still won't run right until you ungunk the carb. It is really time to get a factory manual.<br /><br />DHP

 

[Spike3]

Re: VP-AQ125B valve timing problem

Where is the best place to get a good manual? Does anyone out there have a used one they would like to sell?

 

[Don S]

Re: VP-AQ125B valve timing problem

Go to your local Volvo dealer and have them get you the OEM manual. It's Volvo PN is 7739856. <br />It has all the good information (with pictures) for setting the timing, unlike the aftermarket manuals.

 

[Mischief Managed]

Re: VP-AQ125B valve timing problem

There are marks on the belt; and marks on the cam, intermediate shaft, and crank shaft cogs. They all need to align when the engine is at TDC on the number 1 cylinder, if memory serves. It's been years, but I think the marks are little dots and one cog will have one dot, one will have two dots and the last will have three dots. I seem to recall that you'll need to put an automotive belt on backwards if that's what you use but, again, it's been years.<br /><br />My first boat was a 1984 17.5 foot Sunbird with an AQ125A. Those engines are a joy to work on. So much room to work and it takes about 30 minutes to remove the whole engine.

 

[Spike3]

Re: VP-AQ125B valve timing problem

Thanks for the good advice. So, in order to see the marks on the crank cog wheel, I would have to pull the crank pullys off? I did get the belt from a marine supplier.

 

[Mischief Managed]

Re: VP-AQ125B valve timing problem

Originally posted by Spike3:<br /> Thanks for the good advice. So, in order to see the marks on the crank cog wheel, I would have to pull the crank pullys off? I did get the belt from a marine supplier.

That sounds correct. It's easy to do. IIRC, there are 6 M6 bolts holding the pulley on. That 125 is an amazing simple engine to work on. Only hassle is removing the cooling system and getting all the proper O rings and seals. <br /><br />While you have the heat excahnger off, might as well flush it on the raw water side with muriatic acid. The acid will clean out all the crud and leave the bronze looking brand new and the cooling system working at its best. The acid will also eat the aluminum housing so be sure to only get it on the inside. You'll want to be very careful with the acid around your skin, eyes, clothes, etc. too.