AQ120B Distributor issue after timing belt replacement

[niccio]

Good day, I have a 78' AQ120B that I got from someone who was letting the boat mold in a backyard (for 20 years) that I'm having a bit of an issue with. I just replaced the timing belt and now the distributor will not line up. Here's the skinny:
Timing belt was a Volvo belt with marks
Old belt was trash and rotted/missing teeth, no idea if the motor ran before
Lined up all of the timing marks on the engine
Installed the belt and the timing marks on the belt lined up with the marks on the cogs
Put the engine back together
Did other work (cleaned out carb, etc.)
Fired up the engine and it wouldn't run, seemed like a timing issue
Rotated the distributor as far as it would go advanced and the engine tried to fire
Removed distributor hold down bolt and rotated it a bit more, engine fired and ran

Here's the conundrum. No matter what I do the engine will only run if the distributor is outside of the hold down bolt range. I can pull the dist and move the rotor back, but then the distributor has to be rotated too far back to get the correct timing for the hold down bolt to fit. If I move it forward one gear tooth it sits too far forward. I've checked the timing marks several times and tried rotating the distributor drive shaft one tooth either direction. I also tried moving the distributor and then moving the wire positions to the next tower over. I haven't found any combination of distributor position to wire position to shaft position that will allow me to put in the hold down bolt with the engine at TDC. Does anyone have any ideas?

 

[alldodge]

Pull the dissy and align as needed, then move plug wires in cap instead of rotating dissy

 

[Scott06]

Would think the intermediate shaft that drives the distributor off of it is mistimmed vs the crank and cam . If the belt cover is like the bf230 in my old volvo wagon you probably can pull back the detensioner and remove the upper cover and see the intermediate timing mark , which woud save removing the balancer.

Its nice to work on an engine like this that is non interference...

 

[kenny nunez]

Quite often when I replaced the timing belt on one of these engines and released the tension on the idler pulley the belt would jump a tooth. One way I would check is to start with the markings on the belt aligned with the mark on the sprockets. Remove the spark plugs then spin the engine with the starter in short bursts, if the belt stayed in the correct sprocket teeth then the marking stripes on the belt will return to the original location after about 20 or so revolutions.
I use this same method on the timing chains of the Ford 4.6 engines but turn the engine by hand since it is a interference style engine.

 

[niccio]

Just aqn FYI for anyone who may in the future search for this issue: I found out that the engine had an automotive cap/rotor on it. I replaced it with an OEM Volvo Penta cap and rotor and everything suddenly lined up. Just a good example of how small differences can add up.