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Volvo Penta AQ125 sporadic starting - I believe it is cap related and any help would be awesome!

J

JackBrac

New member
Hello!

I am new to I/O boating world and looking for help. I have an older Bayliner Capri (1989 19' bowrider) that has a Volvo Penta AQ125. I have been using it all summer without issue as the previous own took good care of it. About 2 weeks ago it gave me some trouble when going to start it - I could hear the starter firing but the engine wouldn't turn over. After a few tries, it eventually turned over and started up as it normally would. Once it was warmed up and running, it would start right up over and over. Today, I went to start it and it would not turn over at all, but the starter was still running to try and get it to fire. I started to adjust the main plug on the distributor cap and eventually it turned over and started up. I was able to get it to start a handful of times but not consistently enough to take it out on the water. I pulled the main plug off of the cap and it looked like the cap was chipped (see photo).

My question is - would this be the reason that I can't get it to start consistently? If so, where could I look to purchase a new cap and should I replace more that just this? I have had the boat on the water 30+ times this summer and haven't had any issue with it starting until just recently.

I do get the occasional loud misfire when accelerating and the boat only tops out around 16mph. I know it is older but I thought it would get closer to 25mph. Could all of these things be related? I am looking to repair it quickly as next week is vacation week and we were planning time out on the water. Any help would be awesome and I am happy to venmo for beer compensation!

Thank you!

Jack

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Caps and rotors are normal wear items and when I had a 4 banger Volvo, I replaced the cap, rotor, points/condenser, and plugs every spring before launch ( and retimed the engine!). The points need to be set/adjusted with a dwell meter. When were the wires last replaced?
 
Thanks for sharing this info! I purchased it in the Spring and the previous owner didn't mention the last time he replaced the wires. The don't look new so I would imagine they are over a year old. Could I purchase new wires for this engine online?

Thanks!
 
JackBrac said:
I do get the occasional loud misfire when accelerating and the boat only tops out around 16mph. I know it is older but I thought it would get closer to 25mph.
Click to expand...


These OHC 4 banger ignition distributors are know to become rusty inside.
Rusty/corroded flyweights and governing springs can prevent the advance from working correctly, and will give some of the symptoms that you describe.

If the flyweights are stuck in an advanced position, the engine may want to "buck" when trying to start it.
If the flyweights are rust restricted in their movement, the engine will not see enough advance at the higher RPM range to produce enough power.

Set the contact points via dwell meter..... not just gap!
Gap is an estimate ONLY of correct dwell angle.

When you adjust the advance, be sure to check more than just BASE advance.
Check your engine's progressive and total advance against the OEM ignition advance specs.

Not via Seloc or Clymers manuals............ OEM only!



.
 
Last edited:
RicardoMarine said:




Set the contact points via dwell meter..... not just gap!
Gap is an estimate ONLY of correct dwell angle.



Not via Seloc or Clymers manuals............ OEM only!



.
Click to expand...

Set gap to initially start engine, then use dwell meter to refine.

Seloc and Clymers manuals best for keeping "coffee" rings off furniture :)
 
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