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1989 Volvo Penta AQ131D Accelerating Problems

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Gus147

New member
Engine runs fantastic. Starts perfect and has tons of new parts. Carb rebuild, spark plugs, wires, points, coil, and we also checked the timing and corrected accordingly.

Once we put it in the water and go to accelerate the engine will bog down and almost stall. It sometimes backfires while doing this. Boat runs extremely efficient at idle. What now????
 
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Gus147 said:
Engine runs fantastic. Starts perfect and has tons of new parts. Carb rebuild, spark plugs, wires, points, coil, and we also checked the timing and corrected accordingly.

Once we put it in the water and go to accelerate the engine will bog down and almost stall. It sometimes backfires while doing this. Boat runs extremely efficient at idle. What now????
Click to expand...

When you checked the ignition advance, did you set BASE advance only, or did you look to see what the progressive advance and total advance were?
If not..... that may be your problem.
These distributors are notorious for having advancing mechanism issues.

See your OEM specs for the progressive advance info.

Set BASE advance..... increase RPM as you strobe the timing marks.
Plot the advance out on graph paper.

The actual dynamic advance curve should match the OEM curve.
 
Have not got to see it run properly. Also, what's easiest way to tell which plugs go into the distributor cap....1, 2, 3 ,4?????
 
Gus147 said:
....................... Also, what's easiest way to tell which plugs go into the distributor cap....1, 2, 3 ,4?????
Click to expand...


All engine manufacturers designate the furthest cylinder forward as being the #1 cylinder.
For an inline engine, the cylinder closest to the coolant circulating pump is #1.
The next cylinder behind this would be #2, and so on towards the rear.


Bring #1 cylinder around to TDC on the compression stroke.
When you remove the distributor cap, the rotor should be fairly aligned with the #1 spark plug cable and it's corresponding cap port.
The #3 spark plug cable will be next in the CW direction.... then #4 followed by #2


Do not forget to check the progressive advance and the total advance!
If you are not experienced in doing so, have someone who is check it for you.


Volvo Penta OHC 4 firing order.jpg


 
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