PDA

View Full Version : AQ131A Timing issue



ramdawg
08-18-2009, 08:49 AM
"Replaced cap, rotor, points, condenser, wires, plugs. Set points at 0.016". Set timing at 6 degrees BTDC, 900 rpm. Now it starts hard and when it does run it stalls after 10-15 seconds.

When I play with the timing, I can get it to start and stay running, but timing is set at 15 BTDC. Have tried 10 degrees BTDC, but it would not start the next day.

Should I leave it on 15 BTDC? Anything else to check or adjust?

This is a great motor and boat, usually enjoy it; lately not so happy.

Thanks for any help.

John"

RicardoMarine
08-18-2009, 09:10 AM
"John,
Are you by chance using a digitally advancing timing light?
If so, make sure that it is in "standard mode", or use an old school standard strobe type timing light.

THERE IS NO SUBSTITUTE FOR A STROBE TYPE TIMING LIGHT WHEN WORKING ON THIS ENGINE! PERIOD!
You want to see this in REAL Time and in REAL Degrees.... not via a digital replication of what it THINKS this extremely critical setting should be.
It's just too dang important! IMO.

You may want to check the indexing of the cam timing belt.
This engine should start w/ the base timing that you had set it to.
This engine will not normally and/or easily start with 15* BTDC BASE timing.

See your OEM specs and make sure that you also address TAT (total advance timing) while doing all of this.
TA is equally, if not more, important than BASE advance.

Start with the indexing of the drive belt! This could throw everything out of whack!

Also John, while not as critical w/ the 4 cylinder engine, I'd suggest setting dwell, rather than setting "gap" for your contact points.
Gap is an estimate ONLY of proper "dwell".

El P.... what are your thoughts on his timing issue?

."

ramdawg
08-18-2009, 09:21 AM
"Old School Snap-on timing light from the 1960's! Timing light set on 0 degrees advance.

I don't have a dwell meter, so I used the feeler gage for the points.

I'll check the TAT next and track down a dwell meter. Thanks for the help!!!"

RicardoMarine
08-18-2009, 09:34 AM
"Well, dwell may not be your immediate issue..... But it would be something to do before all is buttoned up.

Also, checking/setting TA is not going to accomplish much if the cam drive belt is not indexed correctly.
I am not sure how this would be running if the belt were not indexed, but can only imagine that it would throw timing off by quite a bit.

Also check the tensioner/idler pulley. This must roll freely and offer the correct tension on this belt. Again, unrelated to your immediate issue, but is important.

You still need to check indexing in my book.
See your Volvo Penta OEM work shop manual for this. It is very easy to confirm.

Once you confirm that it is either correct, or incorrect, you can move forward.

."

ramdawg
08-18-2009, 04:01 PM
"It was dwell!!!

Initially dwell read 40 degrees. Adjusted to 59 degrees, reset timing to 6 degrees BTDC, idling perfectly.

As soon as I am done with this post, going to the lake to run it.

Thank you for all you help!!! It is greatly appreciated.

John"